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LinearLayoutCompat.javaAPI DocAndroid 5.1 API71912Thu Mar 12 22:22:56 GMT 2015android.support.v7.widget

LinearLayoutCompat

public class LinearLayoutCompat extends android.view.ViewGroup
A Layout that arranges its children in a single column or a single row. The direction of the row can be set by calling {@link #setOrientation(int) setOrientation()}. You can also specify gravity, which specifies the alignment of all the child elements by calling {@link #setGravity(int) setGravity()} or specify that specific children grow to fill up any remaining space in the layout by setting the weight member of {@link LinearLayoutCompat.LayoutParams LinearLayoutCompat.LayoutParams}. The default orientation is horizontal.

See the Linear Layout guide.

Also see {@link LinearLayoutCompat.LayoutParams} for layout attributes

Fields Summary
public static final int
HORIZONTAL
public static final int
VERTICAL
public static final int
SHOW_DIVIDER_NONE
Don't show any dividers.
public static final int
SHOW_DIVIDER_BEGINNING
Show a divider at the beginning of the group.
public static final int
SHOW_DIVIDER_MIDDLE
Show dividers between each item in the group.
public static final int
SHOW_DIVIDER_END
Show a divider at the end of the group.
private boolean
mBaselineAligned
Whether the children of this layout are baseline aligned. Only applicable if {@link #mOrientation} is horizontal.
private int
mBaselineAlignedChildIndex
If this layout is part of another layout that is baseline aligned, use the child at this index as the baseline. Note: this is orthogonal to {@link #mBaselineAligned}, which is concerned with whether the children of this layout are baseline aligned.
private int
mBaselineChildTop
The additional offset to the child's baseline. We'll calculate the baseline of this layout as we measure vertically; for horizontal linear layouts, the offset of 0 is appropriate.
private int
mOrientation
private int
mGravity
private int
mTotalLength
private float
mWeightSum
private boolean
mUseLargestChild
private int[]
mMaxAscent
private int[]
mMaxDescent
private static final int
VERTICAL_GRAVITY_COUNT
private static final int
INDEX_CENTER_VERTICAL
private static final int
INDEX_TOP
private static final int
INDEX_BOTTOM
private static final int
INDEX_FILL
private android.graphics.drawable.Drawable
mDivider
private int
mDividerWidth
private int
mDividerHeight
private int
mShowDividers
private int
mDividerPadding
Constructors Summary
public LinearLayoutCompat(android.content.Context context)


       
        this(context, null);
public LinearLayoutCompat(android.content.Context context, android.util.AttributeSet attrs)

        this(context, attrs, 0);
public LinearLayoutCompat(android.content.Context context, android.util.AttributeSet attrs, int defStyleAttr)

        super(context, attrs, defStyleAttr);

        final TintTypedArray a = TintTypedArray.obtainStyledAttributes(context, attrs,
                R.styleable.LinearLayoutCompat, defStyleAttr, 0);

        int index = a.getInt(R.styleable.LinearLayoutCompat_android_orientation, -1);
        if (index >= 0) {
            setOrientation(index);
        }

        index = a.getInt(R.styleable.LinearLayoutCompat_android_gravity, -1);
        if (index >= 0) {
            setGravity(index);
        }

        boolean baselineAligned = a.getBoolean(R.styleable.LinearLayoutCompat_android_baselineAligned, true);
        if (!baselineAligned) {
            setBaselineAligned(baselineAligned);
        }

        mWeightSum = a.getFloat(R.styleable.LinearLayoutCompat_android_weightSum, -1.0f);

        mBaselineAlignedChildIndex =
                a.getInt(R.styleable.LinearLayoutCompat_android_baselineAlignedChildIndex, -1);

        mUseLargestChild = a.getBoolean(R.styleable.LinearLayoutCompat_measureWithLargestChild, false);

        setDividerDrawable(a.getDrawable(R.styleable.LinearLayoutCompat_divider));
        mShowDividers = a.getInt(R.styleable.LinearLayoutCompat_showDividers, SHOW_DIVIDER_NONE);
        mDividerPadding = a.getDimensionPixelSize(R.styleable.LinearLayoutCompat_dividerPadding, 0);

        a.recycle();
Methods Summary
protected booleancheckLayoutParams(ViewGroup.LayoutParams p)

        return p instanceof LinearLayoutCompat.LayoutParams;
voiddrawDividersHorizontal(android.graphics.Canvas canvas)

        final int count = getVirtualChildCount();
        final boolean isLayoutRtl = ViewUtils.isLayoutRtl(this);
        for (int i = 0; i < count; i++) {
            final View child = getVirtualChildAt(i);

            if (child != null && child.getVisibility() != GONE) {
                if (hasDividerBeforeChildAt(i)) {
                    final LayoutParams lp = (LayoutParams) child.getLayoutParams();
                    final int position;
                    if (isLayoutRtl) {
                        position = child.getRight() + lp.rightMargin;
                    } else {
                        position = child.getLeft() - lp.leftMargin - mDividerWidth;
                    }
                    drawVerticalDivider(canvas, position);
                }
            }
        }

        if (hasDividerBeforeChildAt(count)) {
            final View child = getVirtualChildAt(count - 1);
            int position;
            if (child == null) {
                if (isLayoutRtl) {
                    position = getPaddingLeft();
                } else {
                    position = getWidth() - getPaddingRight() - mDividerWidth;
                }
            } else {
                final LayoutParams lp = (LayoutParams) child.getLayoutParams();
                if (isLayoutRtl) {
                    position = child.getLeft() - lp.leftMargin - mDividerWidth;
                } else {
                    position = child.getRight() + lp.rightMargin;
                }
            }
            drawVerticalDivider(canvas, position);
        }
voiddrawDividersVertical(android.graphics.Canvas canvas)

        final int count = getVirtualChildCount();
        for (int i = 0; i < count; i++) {
            final View child = getVirtualChildAt(i);

            if (child != null && child.getVisibility() != GONE) {
                if (hasDividerBeforeChildAt(i)) {
                    final LayoutParams lp = (LayoutParams) child.getLayoutParams();
                    final int top = child.getTop() - lp.topMargin - mDividerHeight;
                    drawHorizontalDivider(canvas, top);
                }
            }
        }

        if (hasDividerBeforeChildAt(count)) {
            final View child = getVirtualChildAt(count - 1);
            int bottom = 0;
            if (child == null) {
                bottom = getHeight() - getPaddingBottom() - mDividerHeight;
            } else {
                final LayoutParams lp = (LayoutParams) child.getLayoutParams();
                bottom = child.getBottom() + lp.bottomMargin;
            }
            drawHorizontalDivider(canvas, bottom);
        }
voiddrawHorizontalDivider(android.graphics.Canvas canvas, int top)

        mDivider.setBounds(getPaddingLeft() + mDividerPadding, top,
                getWidth() - getPaddingRight() - mDividerPadding, top + mDividerHeight);
        mDivider.draw(canvas);
voiddrawVerticalDivider(android.graphics.Canvas canvas, int left)

        mDivider.setBounds(left, getPaddingTop() + mDividerPadding,
                left + mDividerWidth, getHeight() - getPaddingBottom() - mDividerPadding);
        mDivider.draw(canvas);
private voidforceUniformHeight(int count, int widthMeasureSpec)

        // Pretend that the linear layout has an exact size. This is the measured height of
        // ourselves. The measured height should be the max height of the children, changed
        // to accommodate the heightMeasureSpec from the parent
        int uniformMeasureSpec = MeasureSpec.makeMeasureSpec(getMeasuredHeight(),
                MeasureSpec.EXACTLY);
        for (int i = 0; i < count; ++i) {
            final View child = getVirtualChildAt(i);
            if (child.getVisibility() != GONE) {
                LinearLayoutCompat.LayoutParams lp = (LinearLayoutCompat.LayoutParams) child.getLayoutParams();

                if (lp.height == LayoutParams.MATCH_PARENT) {
                    // Temporarily force children to reuse their old measured width
                    // FIXME: this may not be right for something like wrapping text?
                    int oldWidth = lp.width;
                    lp.width = child.getMeasuredWidth();

                    // Remeasure with new dimensions
                    measureChildWithMargins(child, widthMeasureSpec, 0, uniformMeasureSpec, 0);
                    lp.width = oldWidth;
                }
            }
        }
private voidforceUniformWidth(int count, int heightMeasureSpec)

        // Pretend that the linear layout has an exact size.
        int uniformMeasureSpec = MeasureSpec.makeMeasureSpec(getMeasuredWidth(),
                MeasureSpec.EXACTLY);
        for (int i = 0; i< count; ++i) {
            final View child = getVirtualChildAt(i);
            if (child.getVisibility() != GONE) {
                LinearLayoutCompat.LayoutParams lp = ((LinearLayoutCompat.LayoutParams)child.getLayoutParams());

                if (lp.width == LayoutParams.MATCH_PARENT) {
                    // Temporarily force children to reuse their old measured height
                    // FIXME: this may not be right for something like wrapping text?
                    int oldHeight = lp.height;
                    lp.height = child.getMeasuredHeight();

                    // Remeasue with new dimensions
                    measureChildWithMargins(child, uniformMeasureSpec, 0, heightMeasureSpec, 0);
                    lp.height = oldHeight;
                }
            }
        }
protected android.support.v7.widget.LinearLayoutCompat$LayoutParamsgenerateDefaultLayoutParams()
Returns a set of layout parameters with a width of {@link android.view.ViewGroup.LayoutParams#MATCH_PARENT} and a height of {@link android.view.ViewGroup.LayoutParams#WRAP_CONTENT} when the layout's orientation is {@link #VERTICAL}. When the orientation is {@link #HORIZONTAL}, the width is set to {@link LayoutParams#WRAP_CONTENT} and the height to {@link LayoutParams#WRAP_CONTENT}.

        if (mOrientation == HORIZONTAL) {
            return new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
        } else if (mOrientation == VERTICAL) {
            return new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
        }
        return null;
public android.support.v7.widget.LinearLayoutCompat$LayoutParamsgenerateLayoutParams(android.util.AttributeSet attrs)

        return new LinearLayoutCompat.LayoutParams(getContext(), attrs);
protected android.support.v7.widget.LinearLayoutCompat$LayoutParamsgenerateLayoutParams(ViewGroup.LayoutParams p)

        return new LayoutParams(p);
public intgetBaseline()

        if (mBaselineAlignedChildIndex < 0) {
            return super.getBaseline();
        }

        if (getChildCount() <= mBaselineAlignedChildIndex) {
            throw new RuntimeException("mBaselineAlignedChildIndex of LinearLayout "
                    + "set to an index that is out of bounds.");
        }

        final View child = getChildAt(mBaselineAlignedChildIndex);
        final int childBaseline = child.getBaseline();

        if (childBaseline == -1) {
            if (mBaselineAlignedChildIndex == 0) {
                // this is just the default case, safe to return -1
                return -1;
            }
            // the user picked an index that points to something that doesn't
            // know how to calculate its baseline.
            throw new RuntimeException("mBaselineAlignedChildIndex of LinearLayout "
                    + "points to a View that doesn't know how to get its baseline.");
        }

        // TODO: This should try to take into account the virtual offsets
        // (See getNextLocationOffset and getLocationOffset)
        // We should add to childTop:
        // sum([getNextLocationOffset(getChildAt(i)) / i < mBaselineAlignedChildIndex])
        // and also add:
        // getLocationOffset(child)
        int childTop = mBaselineChildTop;

        if (mOrientation == VERTICAL) {
            final int majorGravity = mGravity & Gravity.VERTICAL_GRAVITY_MASK;
            if (majorGravity != Gravity.TOP) {
                switch (majorGravity) {
                    case Gravity.BOTTOM:
                        childTop = getBottom() - getTop() - getPaddingBottom() - mTotalLength;
                        break;

                    case Gravity.CENTER_VERTICAL:
                        childTop += ((getBottom() - getTop() - getPaddingTop() - getPaddingBottom()) -
                                mTotalLength) / 2;
                        break;
                }
            }
        }

        LinearLayoutCompat.LayoutParams lp = (LinearLayoutCompat.LayoutParams) child.getLayoutParams();
        return childTop + lp.topMargin + childBaseline;
public intgetBaselineAlignedChildIndex()

return
The index of the child that will be used if this layout is part of a larger layout that is baseline aligned, or -1 if none has been set.

        return mBaselineAlignedChildIndex;
intgetChildrenSkipCount(android.view.View child, int index)

Returns the number of children to skip after measuring/laying out the specified child.

param
child the child after which we want to skip children
param
index the index of the child after which we want to skip children
return
the number of children to skip, 0 by default

        return 0;
public android.graphics.drawable.DrawablegetDividerDrawable()

return
the divider Drawable that will divide each item.
see
#setDividerDrawable(Drawable)

        return mDivider;
public intgetDividerPadding()
Get the padding size used to inset dividers in pixels

see
#setShowDividers(int)
see
#setDividerDrawable(Drawable)
see
#setDividerPadding(int)

        return mDividerPadding;
public intgetDividerWidth()
Get the width of the current divider drawable.

hide
Used internally by framework.

        return mDividerWidth;
intgetLocationOffset(android.view.View child)

Return the location offset of the specified child. This can be used by subclasses to change the location of a given widget.

param
child the child for which to obtain the location offset
return
the location offset in pixels

        return 0;
intgetNextLocationOffset(android.view.View child)

Return the size offset of the next sibling of the specified child. This can be used by subclasses to change the location of the widget following child.

param
child the child whose next sibling will be moved
return
the location offset of the next child in pixels

        return 0;
public intgetOrientation()
Returns the current orientation.

return
either {@link #HORIZONTAL} or {@link #VERTICAL}

        return mOrientation;
public intgetShowDividers()

return
A flag set indicating how dividers should be shown around items.
see
#setShowDividers(int)

        return mShowDividers;
android.view.ViewgetVirtualChildAt(int index)

Returns the view at the specified index. This method can be overriden to take into account virtual children. Refer to {@link android.widget.TableLayout} and {@link android.widget.TableRow} for an example.

param
index the child's index
return
the child at the specified index

        return getChildAt(index);
intgetVirtualChildCount()

Returns the virtual number of children. This number might be different than the actual number of children if the layout can hold virtual children. Refer to {@link android.widget.TableLayout} and {@link android.widget.TableRow} for an example.

return
the virtual number of children

        return getChildCount();
public floatgetWeightSum()
Returns the desired weights sum.

return
A number greater than 0.0f if the weight sum is defined, or a number lower than or equals to 0.0f if not weight sum is to be used.

        return mWeightSum;
protected booleanhasDividerBeforeChildAt(int childIndex)
Determines where to position dividers between children.

param
childIndex Index of child to check for preceding divider
return
true if there should be a divider before the child at childIndex
hide
Pending API consideration. Currently only used internally by the system.

        if (childIndex == 0) {
            return (mShowDividers & SHOW_DIVIDER_BEGINNING) != 0;
        } else if (childIndex == getChildCount()) {
            return (mShowDividers & SHOW_DIVIDER_END) != 0;
        } else if ((mShowDividers & SHOW_DIVIDER_MIDDLE) != 0) {
            boolean hasVisibleViewBefore = false;
            for (int i = childIndex - 1; i >= 0; i--) {
                if (getChildAt(i).getVisibility() != GONE) {
                    hasVisibleViewBefore = true;
                    break;
                }
            }
            return hasVisibleViewBefore;
        }
        return false;
public booleanisBaselineAligned()

Indicates whether widgets contained within this layout are aligned on their baseline or not.

return
true when widgets are baseline-aligned, false otherwise

        return mBaselineAligned;
public booleanisMeasureWithLargestChildEnabled()
When true, all children with a weight will be considered having the minimum size of the largest child. If false, all children are measured normally.

return
True to measure children with a weight using the minimum size of the largest child, false otherwise.

        return mUseLargestChild;
voidlayoutHorizontal(int left, int top, int right, int bottom)
Position the children during a layout pass if the orientation of this LinearLayout is set to {@link #HORIZONTAL}.

see
#getOrientation()
see
#setOrientation(int)
see
#onLayout(boolean, int, int, int, int)
param
left
param
top
param
right
param
bottom

        final boolean isLayoutRtl = ViewUtils.isLayoutRtl(this);
        final int paddingTop = getPaddingTop();

        int childTop;
        int childLeft;

        // Where bottom of child should go
        final int height = bottom - top;
        int childBottom = height - getPaddingBottom();

        // Space available for child
        int childSpace = height - paddingTop - getPaddingBottom();

        final int count = getVirtualChildCount();

        final int majorGravity = mGravity & GravityCompat.RELATIVE_HORIZONTAL_GRAVITY_MASK;
        final int minorGravity = mGravity & Gravity.VERTICAL_GRAVITY_MASK;

        final boolean baselineAligned = mBaselineAligned;

        final int[] maxAscent = mMaxAscent;
        final int[] maxDescent = mMaxDescent;

        final int layoutDirection = ViewCompat.getLayoutDirection(this);
        switch (GravityCompat.getAbsoluteGravity(majorGravity, layoutDirection)) {
            case Gravity.RIGHT:
                // mTotalLength contains the padding already
                childLeft = getPaddingLeft() + right - left - mTotalLength;
                break;

            case Gravity.CENTER_HORIZONTAL:
                // mTotalLength contains the padding already
                childLeft = getPaddingLeft() + (right - left - mTotalLength) / 2;
                break;

            case Gravity.LEFT:
            default:
                childLeft = getPaddingLeft();
                break;
        }

        int start = 0;
        int dir = 1;
        //In case of RTL, start drawing from the last child.
        if (isLayoutRtl) {
            start = count - 1;
            dir = -1;
        }

        for (int i = 0; i < count; i++) {
            int childIndex = start + dir * i;
            final View child = getVirtualChildAt(childIndex);

            if (child == null) {
                childLeft += measureNullChild(childIndex);
            } else if (child.getVisibility() != GONE) {
                final int childWidth = child.getMeasuredWidth();
                final int childHeight = child.getMeasuredHeight();
                int childBaseline = -1;

                final LinearLayoutCompat.LayoutParams lp =
                        (LinearLayoutCompat.LayoutParams) child.getLayoutParams();

                if (baselineAligned && lp.height != LayoutParams.MATCH_PARENT) {
                    childBaseline = child.getBaseline();
                }

                int gravity = lp.gravity;
                if (gravity < 0) {
                    gravity = minorGravity;
                }

                switch (gravity & Gravity.VERTICAL_GRAVITY_MASK) {
                    case Gravity.TOP:
                        childTop = paddingTop + lp.topMargin;
                        if (childBaseline != -1) {
                            childTop += maxAscent[INDEX_TOP] - childBaseline;
                        }
                        break;

                    case Gravity.CENTER_VERTICAL:
                        // Removed support for baseline alignment when layout_gravity or
                        // gravity == center_vertical. See bug #1038483.
                        // Keep the code around if we need to re-enable this feature
                        // if (childBaseline != -1) {
                        //     // Align baselines vertically only if the child is smaller than us
                        //     if (childSpace - childHeight > 0) {
                        //         childTop = paddingTop + (childSpace / 2) - childBaseline;
                        //     } else {
                        //         childTop = paddingTop + (childSpace - childHeight) / 2;
                        //     }
                        // } else {
                        childTop = paddingTop + ((childSpace - childHeight) / 2)
                                + lp.topMargin - lp.bottomMargin;
                        break;

                    case Gravity.BOTTOM:
                        childTop = childBottom - childHeight - lp.bottomMargin;
                        if (childBaseline != -1) {
                            int descent = child.getMeasuredHeight() - childBaseline;
                            childTop -= (maxDescent[INDEX_BOTTOM] - descent);
                        }
                        break;
                    default:
                        childTop = paddingTop;
                        break;
                }

                if (hasDividerBeforeChildAt(childIndex)) {
                    childLeft += mDividerWidth;
                }

                childLeft += lp.leftMargin;
                setChildFrame(child, childLeft + getLocationOffset(child), childTop,
                        childWidth, childHeight);
                childLeft += childWidth + lp.rightMargin +
                        getNextLocationOffset(child);

                i += getChildrenSkipCount(child, childIndex);
            }
        }
voidlayoutVertical(int left, int top, int right, int bottom)
Position the children during a layout pass if the orientation of this LinearLayout is set to {@link #VERTICAL}.

see
#getOrientation()
see
#setOrientation(int)
see
#onLayout(boolean, int, int, int, int)
param
left
param
top
param
right
param
bottom

        final int paddingLeft = getPaddingLeft();

        int childTop;
        int childLeft;

        // Where right end of child should go
        final int width = right - left;
        int childRight = width - getPaddingRight();

        // Space available for child
        int childSpace = width - paddingLeft - getPaddingRight();

        final int count = getVirtualChildCount();

        final int majorGravity = mGravity & Gravity.VERTICAL_GRAVITY_MASK;
        final int minorGravity = mGravity & GravityCompat.RELATIVE_HORIZONTAL_GRAVITY_MASK;

        switch (majorGravity) {
            case Gravity.BOTTOM:
                // mTotalLength contains the padding already
                childTop = getPaddingTop() + bottom - top - mTotalLength;
                break;

            // mTotalLength contains the padding already
            case Gravity.CENTER_VERTICAL:
                childTop = getPaddingTop() + (bottom - top - mTotalLength) / 2;
                break;

            case Gravity.TOP:
            default:
                childTop = getPaddingTop();
                break;
        }

        for (int i = 0; i < count; i++) {
            final View child = getVirtualChildAt(i);
            if (child == null) {
                childTop += measureNullChild(i);
            } else if (child.getVisibility() != GONE) {
                final int childWidth = child.getMeasuredWidth();
                final int childHeight = child.getMeasuredHeight();

                final LinearLayoutCompat.LayoutParams lp =
                        (LinearLayoutCompat.LayoutParams) child.getLayoutParams();

                int gravity = lp.gravity;
                if (gravity < 0) {
                    gravity = minorGravity;
                }
                final int layoutDirection = ViewCompat.getLayoutDirection(this);
                final int absoluteGravity = GravityCompat.getAbsoluteGravity(gravity,
                        layoutDirection);
                switch (absoluteGravity & Gravity.HORIZONTAL_GRAVITY_MASK) {
                    case Gravity.CENTER_HORIZONTAL:
                        childLeft = paddingLeft + ((childSpace - childWidth) / 2)
                                + lp.leftMargin - lp.rightMargin;
                        break;

                    case Gravity.RIGHT:
                        childLeft = childRight - childWidth - lp.rightMargin;
                        break;

                    case Gravity.LEFT:
                    default:
                        childLeft = paddingLeft + lp.leftMargin;
                        break;
                }

                if (hasDividerBeforeChildAt(i)) {
                    childTop += mDividerHeight;
                }

                childTop += lp.topMargin;
                setChildFrame(child, childLeft, childTop + getLocationOffset(child),
                        childWidth, childHeight);
                childTop += childHeight + lp.bottomMargin + getNextLocationOffset(child);

                i += getChildrenSkipCount(child, i);
            }
        }
voidmeasureChildBeforeLayout(android.view.View child, int childIndex, int widthMeasureSpec, int totalWidth, int heightMeasureSpec, int totalHeight)

Measure the child according to the parent's measure specs. This method should be overriden by subclasses to force the sizing of children. This method is called by {@link #measureVertical(int, int)} and {@link #measureHorizontal(int, int)}.

param
child the child to measure
param
childIndex the index of the child in this view
param
widthMeasureSpec horizontal space requirements as imposed by the parent
param
totalWidth extra space that has been used up by the parent horizontally
param
heightMeasureSpec vertical space requirements as imposed by the parent
param
totalHeight extra space that has been used up by the parent vertically

        measureChildWithMargins(child, widthMeasureSpec, totalWidth,
                heightMeasureSpec, totalHeight);
voidmeasureHorizontal(int widthMeasureSpec, int heightMeasureSpec)
Measures the children when the orientation of this LinearLayout is set to {@link #HORIZONTAL}.

param
widthMeasureSpec Horizontal space requirements as imposed by the parent.
param
heightMeasureSpec Vertical space requirements as imposed by the parent.
see
#getOrientation()
see
#setOrientation(int)
see
#onMeasure(int, int)

        mTotalLength = 0;
        int maxHeight = 0;
        int childState = 0;
        int alternativeMaxHeight = 0;
        int weightedMaxHeight = 0;
        boolean allFillParent = true;
        float totalWeight = 0;

        final int count = getVirtualChildCount();

        final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        final int heightMode = MeasureSpec.getMode(heightMeasureSpec);

        boolean matchHeight = false;
        boolean skippedMeasure = false;

        if (mMaxAscent == null || mMaxDescent == null) {
            mMaxAscent = new int[VERTICAL_GRAVITY_COUNT];
            mMaxDescent = new int[VERTICAL_GRAVITY_COUNT];
        }

        final int[] maxAscent = mMaxAscent;
        final int[] maxDescent = mMaxDescent;

        maxAscent[0] = maxAscent[1] = maxAscent[2] = maxAscent[3] = -1;
        maxDescent[0] = maxDescent[1] = maxDescent[2] = maxDescent[3] = -1;

        final boolean baselineAligned = mBaselineAligned;
        final boolean useLargestChild = mUseLargestChild;

        final boolean isExactly = widthMode == MeasureSpec.EXACTLY;

        int largestChildWidth = Integer.MIN_VALUE;

        // See how wide everyone is. Also remember max height.
        for (int i = 0; i < count; ++i) {
            final View child = getVirtualChildAt(i);

            if (child == null) {
                mTotalLength += measureNullChild(i);
                continue;
            }

            if (child.getVisibility() == GONE) {
                i += getChildrenSkipCount(child, i);
                continue;
            }

            if (hasDividerBeforeChildAt(i)) {
                mTotalLength += mDividerWidth;
            }

            final LinearLayoutCompat.LayoutParams lp = (LinearLayoutCompat.LayoutParams)
                    child.getLayoutParams();

            totalWeight += lp.weight;

            if (widthMode == MeasureSpec.EXACTLY && lp.width == 0 && lp.weight > 0) {
                // Optimization: don't bother measuring children who are going to use
                // leftover space. These views will get measured again down below if
                // there is any leftover space.
                if (isExactly) {
                    mTotalLength += lp.leftMargin + lp.rightMargin;
                } else {
                    final int totalLength = mTotalLength;
                    mTotalLength = Math.max(totalLength, totalLength +
                            lp.leftMargin + lp.rightMargin);
                }

                // Baseline alignment requires to measure widgets to obtain the
                // baseline offset (in particular for TextViews). The following
                // defeats the optimization mentioned above. Allow the child to
                // use as much space as it wants because we can shrink things
                // later (and re-measure).
                if (baselineAligned) {
                    final int freeSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
                    child.measure(freeSpec, freeSpec);
                } else {
                    skippedMeasure = true;
                }
            } else {
                int oldWidth = Integer.MIN_VALUE;

                if (lp.width == 0 && lp.weight > 0) {
                    // widthMode is either UNSPECIFIED or AT_MOST, and this
                    // child
                    // wanted to stretch to fill available space. Translate that to
                    // WRAP_CONTENT so that it does not end up with a width of 0
                    oldWidth = 0;
                    lp.width = LayoutParams.WRAP_CONTENT;
                }

                // Determine how big this child would like to be. If this or
                // previous children have given a weight, then we allow it to
                // use all available space (and we will shrink things later
                // if needed).
                measureChildBeforeLayout(child, i, widthMeasureSpec,
                        totalWeight == 0 ? mTotalLength : 0,
                        heightMeasureSpec, 0);

                if (oldWidth != Integer.MIN_VALUE) {
                    lp.width = oldWidth;
                }

                final int childWidth = child.getMeasuredWidth();
                if (isExactly) {
                    mTotalLength += childWidth + lp.leftMargin + lp.rightMargin +
                            getNextLocationOffset(child);
                } else {
                    final int totalLength = mTotalLength;
                    mTotalLength = Math.max(totalLength, totalLength + childWidth + lp.leftMargin +
                            lp.rightMargin + getNextLocationOffset(child));
                }

                if (useLargestChild) {
                    largestChildWidth = Math.max(childWidth, largestChildWidth);
                }
            }

            boolean matchHeightLocally = false;
            if (heightMode != MeasureSpec.EXACTLY && lp.height == LayoutParams.MATCH_PARENT) {
                // The height of the linear layout will scale, and at least one
                // child said it wanted to match our height. Set a flag indicating that
                // we need to remeasure at least that view when we know our height.
                matchHeight = true;
                matchHeightLocally = true;
            }

            final int margin = lp.topMargin + lp.bottomMargin;
            final int childHeight = child.getMeasuredHeight() + margin;
            childState = ViewUtils.combineMeasuredStates(childState,
                    ViewCompat.getMeasuredState(child));

            if (baselineAligned) {
                final int childBaseline = child.getBaseline();
                if (childBaseline != -1) {
                    // Translates the child's vertical gravity into an index
                    // in the range 0..VERTICAL_GRAVITY_COUNT
                    final int gravity = (lp.gravity < 0 ? mGravity : lp.gravity)
                            & Gravity.VERTICAL_GRAVITY_MASK;
                    final int index = ((gravity >> Gravity.AXIS_Y_SHIFT)
                            & ~Gravity.AXIS_SPECIFIED) >> 1;

                    maxAscent[index] = Math.max(maxAscent[index], childBaseline);
                    maxDescent[index] = Math.max(maxDescent[index], childHeight - childBaseline);
                }
            }

            maxHeight = Math.max(maxHeight, childHeight);

            allFillParent = allFillParent && lp.height == LayoutParams.MATCH_PARENT;
            if (lp.weight > 0) {
                /*
                 * Heights of weighted Views are bogus if we end up
                 * remeasuring, so keep them separate.
                 */
                weightedMaxHeight = Math.max(weightedMaxHeight,
                        matchHeightLocally ? margin : childHeight);
            } else {
                alternativeMaxHeight = Math.max(alternativeMaxHeight,
                        matchHeightLocally ? margin : childHeight);
            }

            i += getChildrenSkipCount(child, i);
        }

        if (mTotalLength > 0 && hasDividerBeforeChildAt(count)) {
            mTotalLength += mDividerWidth;
        }

        // Check mMaxAscent[INDEX_TOP] first because it maps to Gravity.TOP,
        // the most common case
        if (maxAscent[INDEX_TOP] != -1 ||
                maxAscent[INDEX_CENTER_VERTICAL] != -1 ||
                maxAscent[INDEX_BOTTOM] != -1 ||
                maxAscent[INDEX_FILL] != -1) {
            final int ascent = Math.max(maxAscent[INDEX_FILL],
                    Math.max(maxAscent[INDEX_CENTER_VERTICAL],
                            Math.max(maxAscent[INDEX_TOP], maxAscent[INDEX_BOTTOM])));
            final int descent = Math.max(maxDescent[INDEX_FILL],
                    Math.max(maxDescent[INDEX_CENTER_VERTICAL],
                            Math.max(maxDescent[INDEX_TOP], maxDescent[INDEX_BOTTOM])));
            maxHeight = Math.max(maxHeight, ascent + descent);
        }

        if (useLargestChild &&
                (widthMode == MeasureSpec.AT_MOST || widthMode == MeasureSpec.UNSPECIFIED)) {
            mTotalLength = 0;

            for (int i = 0; i < count; ++i) {
                final View child = getVirtualChildAt(i);

                if (child == null) {
                    mTotalLength += measureNullChild(i);
                    continue;
                }

                if (child.getVisibility() == GONE) {
                    i += getChildrenSkipCount(child, i);
                    continue;
                }

                final LinearLayoutCompat.LayoutParams lp = (LinearLayoutCompat.LayoutParams)
                        child.getLayoutParams();
                if (isExactly) {
                    mTotalLength += largestChildWidth + lp.leftMargin + lp.rightMargin +
                            getNextLocationOffset(child);
                } else {
                    final int totalLength = mTotalLength;
                    mTotalLength = Math.max(totalLength, totalLength + largestChildWidth +
                            lp.leftMargin + lp.rightMargin + getNextLocationOffset(child));
                }
            }
        }

        // Add in our padding
        mTotalLength += getPaddingLeft() + getPaddingRight();

        int widthSize = mTotalLength;

        // Check against our minimum width
        widthSize = Math.max(widthSize, getSuggestedMinimumWidth());

        // Reconcile our calculated size with the widthMeasureSpec
        int widthSizeAndState = ViewCompat.resolveSizeAndState(widthSize, widthMeasureSpec, 0);
        widthSize = widthSizeAndState & ViewCompat.MEASURED_SIZE_MASK;

        // Either expand children with weight to take up available space or
        // shrink them if they extend beyond our current bounds. If we skipped
        // measurement on any children, we need to measure them now.
        int delta = widthSize - mTotalLength;
        if (skippedMeasure || delta != 0 && totalWeight > 0.0f) {
            float weightSum = mWeightSum > 0.0f ? mWeightSum : totalWeight;

            maxAscent[0] = maxAscent[1] = maxAscent[2] = maxAscent[3] = -1;
            maxDescent[0] = maxDescent[1] = maxDescent[2] = maxDescent[3] = -1;
            maxHeight = -1;

            mTotalLength = 0;

            for (int i = 0; i < count; ++i) {
                final View child = getVirtualChildAt(i);

                if (child == null || child.getVisibility() == View.GONE) {
                    continue;
                }

                final LinearLayoutCompat.LayoutParams lp =
                        (LinearLayoutCompat.LayoutParams) child.getLayoutParams();

                float childExtra = lp.weight;
                if (childExtra > 0) {
                    // Child said it could absorb extra space -- give him his share
                    int share = (int) (childExtra * delta / weightSum);
                    weightSum -= childExtra;
                    delta -= share;

                    final int childHeightMeasureSpec = getChildMeasureSpec(
                            heightMeasureSpec,
                            getPaddingTop() + getPaddingBottom() + lp.topMargin + lp.bottomMargin,
                            lp.height);

                    // TODO: Use a field like lp.isMeasured to figure out if this
                    // child has been previously measured
                    if ((lp.width != 0) || (widthMode != MeasureSpec.EXACTLY)) {
                        // child was measured once already above ... base new measurement
                        // on stored values
                        int childWidth = child.getMeasuredWidth() + share;
                        if (childWidth < 0) {
                            childWidth = 0;
                        }

                        child.measure(
                                MeasureSpec.makeMeasureSpec(childWidth, MeasureSpec.EXACTLY),
                                childHeightMeasureSpec);
                    } else {
                        // child was skipped in the loop above. Measure for this first time here
                        child.measure(MeasureSpec.makeMeasureSpec(
                                        share > 0 ? share : 0, MeasureSpec.EXACTLY),
                                childHeightMeasureSpec);
                    }

                    // Child may now not fit in horizontal dimension.
                    childState = ViewUtils.combineMeasuredStates(childState,
                            ViewCompat.getMeasuredState(child) & ViewCompat.MEASURED_STATE_MASK);
                }

                if (isExactly) {
                    mTotalLength += child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin +
                            getNextLocationOffset(child);
                } else {
                    final int totalLength = mTotalLength;
                    mTotalLength = Math.max(totalLength, totalLength + child.getMeasuredWidth() +
                            lp.leftMargin + lp.rightMargin + getNextLocationOffset(child));
                }

                boolean matchHeightLocally = heightMode != MeasureSpec.EXACTLY &&
                        lp.height == LayoutParams.MATCH_PARENT;

                final int margin = lp.topMargin + lp .bottomMargin;
                int childHeight = child.getMeasuredHeight() + margin;
                maxHeight = Math.max(maxHeight, childHeight);
                alternativeMaxHeight = Math.max(alternativeMaxHeight,
                        matchHeightLocally ? margin : childHeight);

                allFillParent = allFillParent && lp.height == LayoutParams.MATCH_PARENT;

                if (baselineAligned) {
                    final int childBaseline = child.getBaseline();
                    if (childBaseline != -1) {
                        // Translates the child's vertical gravity into an index in the range 0..2
                        final int gravity = (lp.gravity < 0 ? mGravity : lp.gravity)
                                & Gravity.VERTICAL_GRAVITY_MASK;
                        final int index = ((gravity >> Gravity.AXIS_Y_SHIFT)
                                & ~Gravity.AXIS_SPECIFIED) >> 1;

                        maxAscent[index] = Math.max(maxAscent[index], childBaseline);
                        maxDescent[index] = Math.max(maxDescent[index],
                                childHeight - childBaseline);
                    }
                }
            }

            // Add in our padding
            mTotalLength += getPaddingLeft() + getPaddingRight();
            // TODO: Should we update widthSize with the new total length?

            // Check mMaxAscent[INDEX_TOP] first because it maps to Gravity.TOP,
            // the most common case
            if (maxAscent[INDEX_TOP] != -1 ||
                    maxAscent[INDEX_CENTER_VERTICAL] != -1 ||
                    maxAscent[INDEX_BOTTOM] != -1 ||
                    maxAscent[INDEX_FILL] != -1) {
                final int ascent = Math.max(maxAscent[INDEX_FILL],
                        Math.max(maxAscent[INDEX_CENTER_VERTICAL],
                                Math.max(maxAscent[INDEX_TOP], maxAscent[INDEX_BOTTOM])));
                final int descent = Math.max(maxDescent[INDEX_FILL],
                        Math.max(maxDescent[INDEX_CENTER_VERTICAL],
                                Math.max(maxDescent[INDEX_TOP], maxDescent[INDEX_BOTTOM])));
                maxHeight = Math.max(maxHeight, ascent + descent);
            }
        } else {
            alternativeMaxHeight = Math.max(alternativeMaxHeight, weightedMaxHeight);

            // We have no limit, so make all weighted views as wide as the largest child.
            // Children will have already been measured once.
            if (useLargestChild && widthMode != MeasureSpec.EXACTLY) {
                for (int i = 0; i < count; i++) {
                    final View child = getVirtualChildAt(i);

                    if (child == null || child.getVisibility() == View.GONE) {
                        continue;
                    }

                    final LinearLayoutCompat.LayoutParams lp =
                            (LinearLayoutCompat.LayoutParams) child.getLayoutParams();

                    float childExtra = lp.weight;
                    if (childExtra > 0) {
                        child.measure(
                                MeasureSpec.makeMeasureSpec(largestChildWidth, MeasureSpec.EXACTLY),
                                MeasureSpec.makeMeasureSpec(child.getMeasuredHeight(),
                                        MeasureSpec.EXACTLY));
                    }
                }
            }
        }

        if (!allFillParent && heightMode != MeasureSpec.EXACTLY) {
            maxHeight = alternativeMaxHeight;
        }

        maxHeight += getPaddingTop() + getPaddingBottom();

        // Check against our minimum height
        maxHeight = Math.max(maxHeight, getSuggestedMinimumHeight());

        setMeasuredDimension(widthSizeAndState | (childState&ViewCompat.MEASURED_STATE_MASK),
                ViewCompat.resolveSizeAndState(maxHeight, heightMeasureSpec,
                        (childState<<ViewCompat.MEASURED_HEIGHT_STATE_SHIFT)));

        if (matchHeight) {
            forceUniformHeight(count, widthMeasureSpec);
        }
intmeasureNullChild(int childIndex)

Returns the size (width or height) that should be occupied by a null child.

param
childIndex the index of the null child
return
the width or height of the child depending on the orientation

        return 0;
voidmeasureVertical(int widthMeasureSpec, int heightMeasureSpec)
Measures the children when the orientation of this LinearLayout is set to {@link #VERTICAL}.

param
widthMeasureSpec Horizontal space requirements as imposed by the parent.
param
heightMeasureSpec Vertical space requirements as imposed by the parent.
see
#getOrientation()
see
#setOrientation(int)
see
#onMeasure(int, int)

        mTotalLength = 0;
        int maxWidth = 0;
        int childState = 0;
        int alternativeMaxWidth = 0;
        int weightedMaxWidth = 0;
        boolean allFillParent = true;
        float totalWeight = 0;

        final int count = getVirtualChildCount();

        final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
        final int heightMode = MeasureSpec.getMode(heightMeasureSpec);

        boolean matchWidth = false;
        boolean skippedMeasure = false;

        final int baselineChildIndex = mBaselineAlignedChildIndex;
        final boolean useLargestChild = mUseLargestChild;

        int largestChildHeight = Integer.MIN_VALUE;

        // See how tall everyone is. Also remember max width.
        for (int i = 0; i < count; ++i) {
            final View child = getVirtualChildAt(i);

            if (child == null) {
                mTotalLength += measureNullChild(i);
                continue;
            }

            if (child.getVisibility() == View.GONE) {
                i += getChildrenSkipCount(child, i);
                continue;
            }

            if (hasDividerBeforeChildAt(i)) {
                mTotalLength += mDividerHeight;
            }

            LinearLayoutCompat.LayoutParams lp = (LinearLayoutCompat.LayoutParams) child.getLayoutParams();

            totalWeight += lp.weight;

            if (heightMode == MeasureSpec.EXACTLY && lp.height == 0 && lp.weight > 0) {
                // Optimization: don't bother measuring children who are going to use
                // leftover space. These views will get measured again down below if
                // there is any leftover space.
                final int totalLength = mTotalLength;
                mTotalLength = Math.max(totalLength, totalLength + lp.topMargin + lp.bottomMargin);
                skippedMeasure = true;
            } else {
                int oldHeight = Integer.MIN_VALUE;

                if (lp.height == 0 && lp.weight > 0) {
                    // heightMode is either UNSPECIFIED or AT_MOST, and this
                    // child wanted to stretch to fill available space.
                    // Translate that to WRAP_CONTENT so that it does not end up
                    // with a height of 0
                    oldHeight = 0;
                    lp.height = LayoutParams.WRAP_CONTENT;
                }

                // Determine how big this child would like to be. If this or
                // previous children have given a weight, then we allow it to
                // use all available space (and we will shrink things later
                // if needed).
                measureChildBeforeLayout(
                        child, i, widthMeasureSpec, 0, heightMeasureSpec,
                        totalWeight == 0 ? mTotalLength : 0);

                if (oldHeight != Integer.MIN_VALUE) {
                    lp.height = oldHeight;
                }

                final int childHeight = child.getMeasuredHeight();
                final int totalLength = mTotalLength;
                mTotalLength = Math.max(totalLength, totalLength + childHeight + lp.topMargin +
                        lp.bottomMargin + getNextLocationOffset(child));

                if (useLargestChild) {
                    largestChildHeight = Math.max(childHeight, largestChildHeight);
                }
            }

            /**
             * If applicable, compute the additional offset to the child's baseline
             * we'll need later when asked {@link #getBaseline}.
             */
            if ((baselineChildIndex >= 0) && (baselineChildIndex == i + 1)) {
                mBaselineChildTop = mTotalLength;
            }

            // if we are trying to use a child index for our baseline, the above
            // book keeping only works if there are no children above it with
            // weight.  fail fast to aid the developer.
            if (i < baselineChildIndex && lp.weight > 0) {
                throw new RuntimeException("A child of LinearLayout with index "
                        + "less than mBaselineAlignedChildIndex has weight > 0, which "
                        + "won't work.  Either remove the weight, or don't set "
                        + "mBaselineAlignedChildIndex.");
            }

            boolean matchWidthLocally = false;
            if (widthMode != MeasureSpec.EXACTLY && lp.width == LayoutParams.MATCH_PARENT) {
                // The width of the linear layout will scale, and at least one
                // child said it wanted to match our width. Set a flag
                // indicating that we need to remeasure at least that view when
                // we know our width.
                matchWidth = true;
                matchWidthLocally = true;
            }

            final int margin = lp.leftMargin + lp.rightMargin;
            final int measuredWidth = child.getMeasuredWidth() + margin;
            maxWidth = Math.max(maxWidth, measuredWidth);
            childState = ViewUtils.combineMeasuredStates(childState,
                    ViewCompat.getMeasuredState(child));

            allFillParent = allFillParent && lp.width == LayoutParams.MATCH_PARENT;
            if (lp.weight > 0) {
                /*
                 * Widths of weighted Views are bogus if we end up
                 * remeasuring, so keep them separate.
                 */
                weightedMaxWidth = Math.max(weightedMaxWidth,
                        matchWidthLocally ? margin : measuredWidth);
            } else {
                alternativeMaxWidth = Math.max(alternativeMaxWidth,
                        matchWidthLocally ? margin : measuredWidth);
            }

            i += getChildrenSkipCount(child, i);
        }

        if (mTotalLength > 0 && hasDividerBeforeChildAt(count)) {
            mTotalLength += mDividerHeight;
        }

        if (useLargestChild &&
                (heightMode == MeasureSpec.AT_MOST || heightMode == MeasureSpec.UNSPECIFIED)) {
            mTotalLength = 0;

            for (int i = 0; i < count; ++i) {
                final View child = getVirtualChildAt(i);

                if (child == null) {
                    mTotalLength += measureNullChild(i);
                    continue;
                }

                if (child.getVisibility() == GONE) {
                    i += getChildrenSkipCount(child, i);
                    continue;
                }

                final LinearLayoutCompat.LayoutParams lp = (LinearLayoutCompat.LayoutParams)
                        child.getLayoutParams();
                // Account for negative margins
                final int totalLength = mTotalLength;
                mTotalLength = Math.max(totalLength, totalLength + largestChildHeight +
                        lp.topMargin + lp.bottomMargin + getNextLocationOffset(child));
            }
        }

        // Add in our padding
        mTotalLength += getPaddingTop() + getPaddingBottom();

        int heightSize = mTotalLength;

        // Check against our minimum height
        heightSize = Math.max(heightSize, getSuggestedMinimumHeight());

        // Reconcile our calculated size with the heightMeasureSpec
        int heightSizeAndState = ViewCompat.resolveSizeAndState(heightSize, heightMeasureSpec, 0);
        heightSize = heightSizeAndState & ViewCompat.MEASURED_SIZE_MASK;

        // Either expand children with weight to take up available space or
        // shrink them if they extend beyond our current bounds. If we skipped
        // measurement on any children, we need to measure them now.
        int delta = heightSize - mTotalLength;
        if (skippedMeasure || delta != 0 && totalWeight > 0.0f) {
            float weightSum = mWeightSum > 0.0f ? mWeightSum : totalWeight;

            mTotalLength = 0;

            for (int i = 0; i < count; ++i) {
                final View child = getVirtualChildAt(i);

                if (child.getVisibility() == View.GONE) {
                    continue;
                }

                LinearLayoutCompat.LayoutParams lp = (LinearLayoutCompat.LayoutParams) child.getLayoutParams();

                float childExtra = lp.weight;
                if (childExtra > 0) {
                    // Child said it could absorb extra space -- give him his share
                    int share = (int) (childExtra * delta / weightSum);
                    weightSum -= childExtra;
                    delta -= share;

                    final int childWidthMeasureSpec = getChildMeasureSpec(widthMeasureSpec,
                            getPaddingLeft() + getPaddingRight() +
                                    lp.leftMargin + lp.rightMargin, lp.width);

                    // TODO: Use a field like lp.isMeasured to figure out if this
                    // child has been previously measured
                    if ((lp.height != 0) || (heightMode != MeasureSpec.EXACTLY)) {
                        // child was measured once already above...
                        // base new measurement on stored values
                        int childHeight = child.getMeasuredHeight() + share;
                        if (childHeight < 0) {
                            childHeight = 0;
                        }

                        child.measure(childWidthMeasureSpec,
                                MeasureSpec.makeMeasureSpec(childHeight, MeasureSpec.EXACTLY));
                    } else {
                        // child was skipped in the loop above.
                        // Measure for this first time here
                        child.measure(childWidthMeasureSpec,
                                MeasureSpec.makeMeasureSpec(share > 0 ? share : 0,
                                        MeasureSpec.EXACTLY));
                    }

                    // Child may now not fit in vertical dimension.
                    childState = ViewUtils.combineMeasuredStates(childState,
                            ViewCompat.getMeasuredState(child) & (ViewCompat.MEASURED_STATE_MASK
                                    >> ViewCompat.MEASURED_HEIGHT_STATE_SHIFT));
                }

                final int margin =  lp.leftMargin + lp.rightMargin;
                final int measuredWidth = child.getMeasuredWidth() + margin;
                maxWidth = Math.max(maxWidth, measuredWidth);

                boolean matchWidthLocally = widthMode != MeasureSpec.EXACTLY &&
                        lp.width == LayoutParams.MATCH_PARENT;

                alternativeMaxWidth = Math.max(alternativeMaxWidth,
                        matchWidthLocally ? margin : measuredWidth);

                allFillParent = allFillParent && lp.width == LayoutParams.MATCH_PARENT;

                final int totalLength = mTotalLength;
                mTotalLength = Math.max(totalLength, totalLength + child.getMeasuredHeight() +
                        lp.topMargin + lp.bottomMargin + getNextLocationOffset(child));
            }

            // Add in our padding
            mTotalLength += getPaddingTop() + getPaddingBottom();
            // TODO: Should we recompute the heightSpec based on the new total length?
        } else {
            alternativeMaxWidth = Math.max(alternativeMaxWidth,
                    weightedMaxWidth);


            // We have no limit, so make all weighted views as tall as the largest child.
            // Children will have already been measured once.
            if (useLargestChild && heightMode != MeasureSpec.EXACTLY) {
                for (int i = 0; i < count; i++) {
                    final View child = getVirtualChildAt(i);

                    if (child == null || child.getVisibility() == View.GONE) {
                        continue;
                    }

                    final LinearLayoutCompat.LayoutParams lp =
                            (LinearLayoutCompat.LayoutParams) child.getLayoutParams();

                    float childExtra = lp.weight;
                    if (childExtra > 0) {
                        child.measure(
                                MeasureSpec.makeMeasureSpec(child.getMeasuredWidth(),
                                        MeasureSpec.EXACTLY),
                                MeasureSpec.makeMeasureSpec(largestChildHeight,
                                        MeasureSpec.EXACTLY));
                    }
                }
            }
        }

        if (!allFillParent && widthMode != MeasureSpec.EXACTLY) {
            maxWidth = alternativeMaxWidth;
        }

        maxWidth += getPaddingLeft() + getPaddingRight();

        // Check against our minimum width
        maxWidth = Math.max(maxWidth, getSuggestedMinimumWidth());

        setMeasuredDimension(ViewCompat.resolveSizeAndState(maxWidth, widthMeasureSpec, childState),
                heightSizeAndState);

        if (matchWidth) {
            forceUniformWidth(count, heightMeasureSpec);
        }
protected voidonDraw(android.graphics.Canvas canvas)

        if (mDivider == null) {
            return;
        }

        if (mOrientation == VERTICAL) {
            drawDividersVertical(canvas);
        } else {
            drawDividersHorizontal(canvas);
        }
public voidonInitializeAccessibilityEvent(android.view.accessibility.AccessibilityEvent event)

        if (Build.VERSION.SDK_INT >= 14) {
            super.onInitializeAccessibilityEvent(event);
            event.setClassName(LinearLayoutCompat.class.getName());
        }
public voidonInitializeAccessibilityNodeInfo(android.view.accessibility.AccessibilityNodeInfo info)

        if (Build.VERSION.SDK_INT >= 14) {
            super.onInitializeAccessibilityNodeInfo(info);
            info.setClassName(LinearLayoutCompat.class.getName());
        }
protected voidonLayout(boolean changed, int l, int t, int r, int b)

        if (mOrientation == VERTICAL) {
            layoutVertical(l, t, r, b);
        } else {
            layoutHorizontal(l, t, r, b);
        }
protected voidonMeasure(int widthMeasureSpec, int heightMeasureSpec)

        if (mOrientation == VERTICAL) {
            measureVertical(widthMeasureSpec, heightMeasureSpec);
        } else {
            measureHorizontal(widthMeasureSpec, heightMeasureSpec);
        }
public voidsetBaselineAligned(boolean baselineAligned)

Defines whether widgets contained in this layout are baseline-aligned or not.

param
baselineAligned true to align widgets on their baseline, false otherwise

        mBaselineAligned = baselineAligned;
public voidsetBaselineAlignedChildIndex(int i)

param
i The index of the child that will be used if this layout is part of a larger layout that is baseline aligned.

        if ((i < 0) || (i >= getChildCount())) {
            throw new IllegalArgumentException("base aligned child index out "
                    + "of range (0, " + getChildCount() + ")");
        }
        mBaselineAlignedChildIndex = i;
private voidsetChildFrame(android.view.View child, int left, int top, int width, int height)

        child.layout(left, top, left + width, top + height);
public voidsetDividerDrawable(android.graphics.drawable.Drawable divider)
Set a drawable to be used as a divider between items.

param
divider Drawable that will divide each item.
see
#setShowDividers(int)

        if (divider == mDivider) {
            return;
        }
        mDivider = divider;
        if (divider != null) {
            mDividerWidth = divider.getIntrinsicWidth();
            mDividerHeight = divider.getIntrinsicHeight();
        } else {
            mDividerWidth = 0;
            mDividerHeight = 0;
        }
        setWillNotDraw(divider == null);
        requestLayout();
public voidsetDividerPadding(int padding)
Set padding displayed on both ends of dividers.

param
padding Padding value in pixels that will be applied to each end
see
#setShowDividers(int)
see
#setDividerDrawable(Drawable)
see
#getDividerPadding()

        mDividerPadding = padding;
public voidsetGravity(int gravity)
Describes how the child views are positioned. Defaults to GRAVITY_TOP. If this layout has a VERTICAL orientation, this controls where all the child views are placed if there is extra vertical space. If this layout has a HORIZONTAL orientation, this controls the alignment of the children.

param
gravity See {@link android.view.Gravity}

        if (mGravity != gravity) {
            if ((gravity & GravityCompat.RELATIVE_HORIZONTAL_GRAVITY_MASK) == 0) {
                gravity |= GravityCompat.START;
            }

            if ((gravity & Gravity.VERTICAL_GRAVITY_MASK) == 0) {
                gravity |= Gravity.TOP;
            }

            mGravity = gravity;
            requestLayout();
        }
public voidsetHorizontalGravity(int horizontalGravity)

        final int gravity = horizontalGravity & GravityCompat.RELATIVE_HORIZONTAL_GRAVITY_MASK;
        if ((mGravity & GravityCompat.RELATIVE_HORIZONTAL_GRAVITY_MASK) != gravity) {
            mGravity = (mGravity & ~GravityCompat.RELATIVE_HORIZONTAL_GRAVITY_MASK) | gravity;
            requestLayout();
        }
public voidsetMeasureWithLargestChildEnabled(boolean enabled)
When set to true, all children with a weight will be considered having the minimum size of the largest child. If false, all children are measured normally. Disabled by default.

param
enabled True to measure children with a weight using the minimum size of the largest child, false otherwise.

        mUseLargestChild = enabled;
public voidsetOrientation(int orientation)
Should the layout be a column or a row.

param
orientation Pass {@link #HORIZONTAL} or {@link #VERTICAL}. Default value is {@link #HORIZONTAL}.

        if (mOrientation != orientation) {
            mOrientation = orientation;
            requestLayout();
        }
public voidsetShowDividers(int showDividers)
Set how dividers should be shown between items in this layout

param
showDividers One or more of {@link #SHOW_DIVIDER_BEGINNING}, {@link #SHOW_DIVIDER_MIDDLE}, or {@link #SHOW_DIVIDER_END}, or {@link #SHOW_DIVIDER_NONE} to show no dividers.

        if (showDividers != mShowDividers) {
            requestLayout();
        }
        mShowDividers = showDividers;
public voidsetVerticalGravity(int verticalGravity)

        final int gravity = verticalGravity & Gravity.VERTICAL_GRAVITY_MASK;
        if ((mGravity & Gravity.VERTICAL_GRAVITY_MASK) != gravity) {
            mGravity = (mGravity & ~Gravity.VERTICAL_GRAVITY_MASK) | gravity;
            requestLayout();
        }
public voidsetWeightSum(float weightSum)
Defines the desired weights sum. If unspecified the weights sum is computed at layout time by adding the layout_weight of each child. This can be used for instance to give a single child 50% of the total available space by giving it a layout_weight of 0.5 and setting the weightSum to 1.0.

param
weightSum a number greater than 0.0f, or a number lower than or equals to 0.0f if the weight sum should be computed from the children's layout_weight

        mWeightSum = Math.max(0.0f, weightSum);
public booleanshouldDelayChildPressedState()

        return false;