/*
* Copyright (C) 2006 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.graphics.drawable;
import java.io.InputStream;
import java.io.IOException;
import java.util.Arrays;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.graphics.*;
import android.util.AttributeSet;
import android.util.StateSet;
import android.util.Xml;
import android.util.TypedValue;
/**
* A Drawable is a general abstraction for "something that can be drawn." Most
* often you will deal with Drawable as the type of resource retrieved for
* drawing things to the screen; the Drawable class provides a generic API for
* dealing with an underlying visual resource that may take a variety of forms.
* Unlike a {@link android.view.View}, a Drawable does not have any facility to
* receive events or otherwise interact with the user.
*
* <p>In addition to simple drawing, Drawable provides a number of generic
* mechanisms for its client to interact with what is being drawn:
*
* <ul>
* <li> The {@link #setBounds} method <var>must</var> be called to tell the
* Drawable where it is drawn and how large it should be. All Drawables
* should respect the requested size, often simply by scaling their
* imagery. A client can find the preferred size for some Drawables with
* the {@link #getIntrinsicHeight} and {@link #getIntrinsicWidth} methods.
*
* <li> The {@link #getPadding} method can return from some Drawables
* information about how to frame content that is placed inside of them.
* For example, a Drawable that is intended to be the frame for a button
* widget would need to return padding that correctly places the label
* inside of itself.
*
* <li> The {@link #setState} method allows the client to tell the Drawable
* in which state it is to be drawn, such as "focused", "selected", etc.
* Some drawables may modify their imagery based on the selected state.
*
* <li> The {@link #setLevel} method allows the client to supply a single
* continuous controller that can modify the Drawable is displayed, such as
* a battery level or progress level. Some drawables may modify their
* imagery based on the current level.
*
* <li> A Drawable can perform animations by calling back to its client
* through the {@link Callback} interface. All clients should support this
* interface (via {@link #setCallback}) so that animations will work. A
* simple way to do this is through the system facilities such as
* {@link android.view.View#setBackgroundDrawable(Drawable)} and
* {@link android.widget.ImageView}.
* </ul>
*
* Though usually not visible to the application, Drawables may take a variety
* of forms:
*
* <ul>
* <li> <b>Bitmap</b>: the simplest Drawable, a PNG or JPEG image.
* <li> <b>Nine Patch</b>: an extension to the PNG format allows it to
* specify information about how to stretch it and place things inside of
* it.
* <li> <b>Shape</b>: contains simple drawing commands instead of a raw
* bitmap, allowing it to resize better in some cases.
* <li> <b>Layers</b>: a compound drawable, which draws multiple underlying
* drawables on top of each other.
* <li> <b>States</b>: a compound drawable that selects one of a set of
* drawables based on its state.
* <li> <b>Levels</b>: a compound drawable that selects one of a set of
* drawables based on its level.
* <li> <b>Scale</b>: a compound drawable with a single child drawable,
* whose overall size is modified based on the current level.
* </ul>
* <p>For information and examples of creating drawable resources (XML or bitmap files that
* can be loaded in code), see <a href="{@docRoot}guide/topics/resources/resources-i18n.html">Resources
* and Internationalization</a>.
*/
public abstract class Drawable {
private int[] mStateSet = StateSet.WILD_CARD;
private int mLevel = 0;
private int mChangingConfigurations = 0;
private Rect mBounds = new Rect();
/*package*/ Callback mCallback = null;
private boolean mVisible = true;
/**
* Draw in its bounds (set via setBounds) respecting optional effects such
* as alpha (set via setAlpha) and color filter (set via setColorFilter).
*
* @param canvas The canvas to draw into
*/
public abstract void draw(Canvas canvas);
/**
* Specify a bounding rectangle for the Drawable. This is where the drawable
* will draw when its draw() method is called.
*/
public void setBounds(int left, int top, int right, int bottom) {
Rect oldBounds = mBounds;
if (oldBounds.left != left || oldBounds.top != top ||
oldBounds.right != right || oldBounds.bottom != bottom) {
mBounds.set(left, top, right, bottom);
onBoundsChange(mBounds);
}
}
/**
* Specify a bounding rectangle for the Drawable. This is where the drawable
* will draw when its draw() method is called.
*/
public void setBounds(Rect bounds) {
setBounds(bounds.left, bounds.top, bounds.right, bounds.bottom);
}
/**
* Return a copy of the drawable's bounds in the specified Rect (allocated
* by the caller). The bounds specify where this will draw when its draw()
* method is called.
*
* @param bounds Rect to receive the drawable's bounds (allocated by the
* caller).
*/
public final void copyBounds(Rect bounds) {
bounds.set(mBounds);
}
/**
* Return a copy of the drawable's bounds in a new Rect. This returns the
* same values as getBounds(), but the returned object is guaranteed to not
* be changed later by the drawable (i.e. it retains no reference to this
* rect). If the caller already has a Rect allocated, call copyBounds(rect)
*
* @return A copy of the drawable's bounds
*/
public final Rect copyBounds() {
return new Rect(mBounds);
}
/**
* Return the drawable's bounds Rect. Note: for efficiency, the returned
* object may be the same object stored in the drawable (though this is not
* guaranteed), so if a persistent copy of the bounds is needed, call
* copyBounds(rect) instead.
*
* @return The bounds of the drawable (which may change later, so caller
* beware).
*/
public final Rect getBounds() {
return mBounds;
}
/**
* Set a mask of the configuration parameters for which this drawable
* may change, requiring that it be re-created.
*
* @param configs A mask of the changing configuration parameters, as
* defined by {@link android.content.res.Configuration}.
*
* @see android.content.res.Configuration
*/
public void setChangingConfigurations(int configs) {
mChangingConfigurations = configs;
}
/**
* Return a mask of the configuration parameters for which this drawable
* mau change, requiring that it be re-created. The default implementation
* returns whatever was provided through
* {@link #setChangingConfigurations(int)} or 0 by default. Subclasses
* may extend this to or in the changing configurations of any other
* drawables they hold.
*
* @return Returns a mask of the changing configuration parameters, as
* defined by {@link android.content.res.Configuration}.
*
* @see android.content.res.Configuration
*/
public int getChangingConfigurations() {
return mChangingConfigurations;
}
/**
* Set to true to have the drawable dither its colors when drawn to a device
* with fewer than 8-bits per color component. This can improve the look on
* those devices, but can also slow down the drawing a little.
*/
public void setDither(boolean dither) {}
/**
* Set to true to have the drawable filter its bitmap when scaled or rotated
* (for drawables that use bitmaps). If the drawable does not use bitmaps,
* this call is ignored. This can improve the look when scaled or rotated,
* but also slows down the drawing.
*/
public void setFilterBitmap(boolean filter) {}
/**
* Implement this interface if you want to create an animated drawable that
* extends {@link android.graphics.drawable.Drawable Drawable}.
* Upon retrieving a drawable, use
* {@link Drawable#setCallback(android.graphics.drawable.Drawable.Callback)}
* to supply your implementation of the interface to the drawable; it uses
* this interface to schedule and execute animation changes.
*/
public static interface Callback {
/**
* Called when the drawable needs to be redrawn. A view at this point
* should invalidate itself (or at least the part of itself where the
* drawable appears).
*
* @param who The drawable that is requesting the update.
*/
public void invalidateDrawable(Drawable who);
/**
* A Drawable can call this to schedule the next frame of its
* animation. An implementation can generally simply call
* {@link android.os.Handler#postAtTime(Runnable, Object, long)} with
* the parameters <var>(what, who, when)</var> to perform the
* scheduling.
*
* @param who The drawable being scheduled.
* @param what The action to execute.
* @param when The time (in milliseconds) to run. The timebase is
* {@link android.os.SystemClock#uptimeMillis}
*/
public void scheduleDrawable(Drawable who, Runnable what, long when);
/**
* A Drawable can call this to unschedule an action previously
* scheduled with {@link #scheduleDrawable}. An implementation can
* generally simply call
* {@link android.os.Handler#removeCallbacks(Runnable, Object)} with
* the parameters <var>(what, who)</var> to unschedule the drawable.
*
* @param who The drawable being unscheduled.
* @param what The action being unscheduled.
*/
public void unscheduleDrawable(Drawable who, Runnable what);
}
/**
* Bind a {@link Callback} object to this Drawable. Required for clients
* that want to support animated drawables.
*
* @param cb The client's Callback implementation.
*/
public final void setCallback(Callback cb) {
mCallback = cb;
}
/**
* Use the current {@link Callback} implementation to have this Drawable
* redrawn. Does nothing if there is no Callback attached to the
* Drawable.
*
* @see Callback#invalidateDrawable
*/
public void invalidateSelf()
{
if (mCallback != null) {
mCallback.invalidateDrawable(this);
}
}
/**
* Use the current {@link Callback} implementation to have this Drawable
* scheduled. Does nothing if there is no Callback attached to the
* Drawable.
*
* @param what The action being scheduled.
* @param when The time (in milliseconds) to run.
*
* @see Callback#scheduleDrawable
*/
public void scheduleSelf(Runnable what, long when)
{
if (mCallback != null) {
mCallback.scheduleDrawable(this, what, when);
}
}
/**
* Use the current {@link Callback} implementation to have this Drawable
* unscheduled. Does nothing if there is no Callback attached to the
* Drawable.
*
* @param what The runnable that you no longer want called.
*
* @see Callback#unscheduleDrawable
*/
public void unscheduleSelf(Runnable what)
{
if (mCallback != null) {
mCallback.unscheduleDrawable(this, what);
}
}
/**
* Specify an alpha value for the drawable. 0 means fully transparent, and
* 255 means fully opaque.
*/
public abstract void setAlpha(int alpha);
/**
* Specify an optional colorFilter for the drawable. Pass null to remove
* any filters.
*/
public abstract void setColorFilter(ColorFilter cf);
/**
* Specify a color and porterduff mode to be the colorfilter for this
* drawable.
*/
public void setColorFilter(int color, PorterDuff.Mode mode) {
setColorFilter(new PorterDuffColorFilter(color, mode));
}
public void clearColorFilter() {
setColorFilter(null);
}
/**
* Indicates whether this view will change its appearance based on state.
* Clients can use this to determine whether it is necessary to calculate
* their state and call setState.
*
* @return True if this view changes its appearance based on state, false
* otherwise.
*
* @see #setState(int[])
*/
public boolean isStateful() {
return false;
}
/**
* Specify a set of states for the drawable. These are use-case specific,
* so see the relevant documentation. As an example, the background for
* widgets like Button understand the following states:
* [{@link android.R.attr#state_focused},
* {@link android.R.attr#state_pressed}].
*
* <p>If the new state you are supplying causes the appearance of the
* Drawable to change, then it is responsible for calling
* {@link #invalidateSelf} in order to have itself redrawn, <em>and</em>
* true will be returned from this function.
*
* <p>Note: The Drawable holds a reference on to <var>stateSet</var>
* until a new state array is given to it, so you must not modify this
* array during that time.</p>
*
* @param stateSet The new set of states to be displayed.
*
* @return Returns true if this change in state has caused the appearance
* of the Drawable to change (hence requiring an invalidate), otherwise
* returns false.
*/
public boolean setState(final int[] stateSet) {
if (!Arrays.equals(mStateSet, stateSet)) {
mStateSet = stateSet;
return onStateChange(stateSet);
}
return false;
}
/**
* Describes the current state, as a union of primitve states, such as
* {@link android.R.attr#state_focused},
* {@link android.R.attr#state_selected}, etc.
* Some drawables may modify their imagery based on the selected state.
* @return An array of resource Ids describing the current state.
*/
public int[] getState() {
return mStateSet;
}
/**
* @return The current drawable that will be used by this drawable. For simple drawables, this
* is just the drawable itself. For drawables that change state like
* {@link StateListDrawable} and {@link LevelListDrawable} this will be the child drawable
* currently in use.
*/
public Drawable getCurrent() {
return this;
}
/**
* Specify the level for the drawable. This allows a drawable to vary its
* imagery based on a continuous controller, for example to show progress
* or volume level.
*
* <p>If the new level you are supplying causes the appearance of the
* Drawable to change, then it is responsible for calling
* {@link #invalidateSelf} in order to have itself redrawn, <em>and</em>
* true will be returned from this function.
*
* @param level The new level, from 0 (minimum) to 10000 (maximum).
*
* @return Returns true if this change in level has caused the appearance
* of the Drawable to change (hence requiring an invalidate), otherwise
* returns false.
*/
public final boolean setLevel(int level) {
if (mLevel != level) {
mLevel = level;
return onLevelChange(level);
}
return false;
}
/**
* Retrieve the current level.
*
* @return int Current level, from 0 (minimum) to 10000 (maximum).
*/
public final int getLevel() {
return mLevel;
}
/**
* Set whether this Drawable is visible. This generally does not impact
* the Drawable's behavior, but is a hint that can be used by some
* Drawables, for example, to decide whether run animations.
*
* @param visible Set to true if visible, false if not.
* @param restart You can supply true here to force the drawable to behave
* as if it has just become visible, even if it had last
* been set visible. Used for example to force animations
* to restart.
*
* @return boolean Returns true if the new visibility is different than
* its previous state.
*/
public boolean setVisible(boolean visible, boolean restart) {
boolean changed = mVisible != visible;
mVisible = visible;
return changed;
}
public final boolean isVisible() {
return mVisible;
}
/**
* Return the opacity/transparency of this Drawable. The returned value is
* one of the abstract format constants in
* {@link android.graphics.PixelFormat}:
* {@link android.graphics.PixelFormat#UNKNOWN},
* {@link android.graphics.PixelFormat#TRANSLUCENT},
* {@link android.graphics.PixelFormat#TRANSPARENT}, or
* {@link android.graphics.PixelFormat#OPAQUE}.
*
* <p>Generally a Drawable should be as conservative as possible with the
* value it returns. For example, if it contains multiple child drawables
* and only shows one of them at a time, if only one of the children is
* TRANSLUCENT and the others are OPAQUE then TRANSLUCENT should be
* returned. You can use the method {@link #resolveOpacity} to perform a
* standard reduction of two opacities to the appropriate single output.
*
* <p>Note that the returned value does <em>not</em> take into account a
* custom alpha or color filter that has been applied by the client through
* the {@link #setAlpha} or {@link #setColorFilter} methods.
*
* @return int The opacity class of the Drawable.
*
* @see android.graphics.PixelFormat
*/
public abstract int getOpacity();
/**
* Return the appropriate opacity value for two source opacities. If
* either is UNKNOWN, that is returned; else, if either is TRANSLUCENT,
* that is returned; else, if either is TRANSPARENT, that is returned;
* else, OPAQUE is returned.
*
* <p>This is to help in implementing {@link #getOpacity}.
*
* @param op1 One opacity value.
* @param op2 Another opacity value.
*
* @return int The combined opacity value.
*
* @see #getOpacity
*/
public static int resolveOpacity(int op1, int op2) {
if (op1 == op2) {
return op1;
}
if (op1 == PixelFormat.UNKNOWN || op2 == PixelFormat.UNKNOWN) {
return PixelFormat.UNKNOWN;
}
if (op1 == PixelFormat.TRANSLUCENT || op2 == PixelFormat.TRANSLUCENT) {
return PixelFormat.TRANSLUCENT;
}
if (op1 == PixelFormat.TRANSPARENT || op2 == PixelFormat.TRANSPARENT) {
return PixelFormat.TRANSPARENT;
}
return PixelFormat.OPAQUE;
}
/**
* Returns a Region representing the part of the Drawable that is completely
* transparent. This can be used to perform drawing operations, identifying
* which parts of the target will not change when rendering the Drawable.
* The default implementation returns null, indicating no transparent
* region; subclasses can optionally override this to return an actual
* Region if they want to supply this optimization information, but it is
* not required that they do so.
*
* @return Returns null if the Drawables has no transparent region to
* report, else a Region holding the parts of the Drawable's bounds that
* are transparent.
*/
public Region getTransparentRegion() {
return null;
}
/**
* Override this in your subclass to change appearance if you recognize the
* specified state.
*
* @return Returns true if the state change has caused the appearance of
* the Drawable to change (that is, it needs to be drawn), else false
* if it looks the same and there is no need to redraw it since its
* last state.
*/
protected boolean onStateChange(int[] state) { return false; }
/** Override this in your subclass to change appearance if you vary based
* on level.
* @return Returns true if the level change has caused the appearance of
* the Drawable to change (that is, it needs to be drawn), else false
* if it looks the same and there is no need to redraw it since its
* last level.
*/
protected boolean onLevelChange(int level) { return false; }
/**
* Override this in your subclass to change appearance if you recognize the
* specified state.
*/
protected void onBoundsChange(Rect bounds) {}
/**
* Return the intrinsic width of the underlying drawable object. Returns
* -1 if it has no intrinsic width, such as with a solid color.
*/
public int getIntrinsicWidth() {
return -1;
}
/**
* Return the intrinsic height of the underlying drawable object. Returns
* -1 if it has no intrinsic height, such as with a solid color.
*/
public int getIntrinsicHeight() {
return -1;
}
/**
* Returns the minimum width suggested by this Drawable. If a View uses this
* Drawable as a background, it is suggested that the View use at least this
* value for its width. (There will be some scenarios where this will not be
* possible.) This value should INCLUDE any padding.
*
* @return The minimum width suggested by this Drawable. If this Drawable
* doesn't have a suggested minimum width, 0 is returned.
*/
public int getMinimumWidth() {
final int intrinsicWidth = getIntrinsicWidth();
return intrinsicWidth > 0 ? intrinsicWidth : 0;
}
/**
* Returns the minimum height suggested by this Drawable. If a View uses this
* Drawable as a background, it is suggested that the View use at least this
* value for its height. (There will be some scenarios where this will not be
* possible.) This value should INCLUDE any padding.
*
* @return The minimum height suggested by this Drawable. If this Drawable
* doesn't have a suggested minimum height, 0 is returned.
*/
public int getMinimumHeight() {
final int intrinsicHeight = getIntrinsicHeight();
return intrinsicHeight > 0 ? intrinsicHeight : 0;
}
/**
* Return in padding the insets suggested by this Drawable for placing
* content inside the drawable's bounds. Positive values move toward the
* center of the Drawable (set Rect.inset). Returns true if this drawable
* actually has a padding, else false. When false is returned, the padding
* is always set to 0.
*/
public boolean getPadding(Rect padding) {
padding.set(0, 0, 0, 0);
return false;
}
/**
* Make this drawable mutable. This operation cannot be reversed. A mutable
* drawable is guaranteed to not share its state with any other drawable.
* This is especially useful when you need to modify properties of drawables
* loaded from resources. By default, all drawables instances loaded from
* the same resource share a common state; if you modify the state of one
* instance, all the other instances will receive the same modification.
*
* Calling this method on a mutable Drawable will have no effect.
*
* @return This drawable.
*/
public Drawable mutate() {
return this;
}
/**
* Create a drawable from an inputstream
*/
public static Drawable createFromStream(InputStream is, String srcName) {
return createFromResourceStream(null, null, is, srcName);
}
/**
* Create a drawable from an inputstream
*
* @hide pending API council approval
*/
public static Drawable createFromResourceStream(Resources res, TypedValue value,
InputStream is, String srcName) {
if (is == null) {
return null;
}
/* ugh. The decodeStream contract is that we have already allocated
the pad rect, but if the bitmap does not had a ninepatch chunk,
then the pad will be ignored. If we could change this to lazily
alloc/assign the rect, we could avoid the GC churn of making new
Rects only to drop them on the floor.
*/
Rect pad = new Rect();
Bitmap bm = BitmapFactory.decodeStream(res, value, is, pad, null);
if (bm != null) {
byte[] np = bm.getNinePatchChunk();
if (np == null || !NinePatch.isNinePatchChunk(np)) {
np = null;
pad = null;
}
return drawableFromBitmap(res, bm, np, pad, srcName);
}
return null;
}
/**
* Create a drawable from an XML document. For more information on how to
* create resources in XML, see
* <a href="{@docRoot}guide/topics/resources/resources-i18n.html">Resources and
* Internationalization</a>.
*/
public static Drawable createFromXml(Resources r, XmlPullParser parser)
throws XmlPullParserException, IOException {
AttributeSet attrs = Xml.asAttributeSet(parser);
int type;
while ((type=parser.next()) != XmlPullParser.START_TAG &&
type != XmlPullParser.END_DOCUMENT) {
// Empty loop
}
if (type != XmlPullParser.START_TAG) {
throw new XmlPullParserException("No start tag found");
}
Drawable drawable = createFromXmlInner(r, parser, attrs);
if (drawable == null) {
throw new RuntimeException("Unknown initial tag: " + parser.getName());
}
return drawable;
}
/**
* Create from inside an XML document. Called on a parser positioned at
* a tag in an XML document, tries to create a Drawable from that tag.
* Returns null if the tag is not a valid drawable.
*/
public static Drawable createFromXmlInner(Resources r, XmlPullParser parser, AttributeSet attrs)
throws XmlPullParserException, IOException {
Drawable drawable;
final String name = parser.getName();
if (name.equals("selector")) {
drawable = new StateListDrawable();
} else if (name.equals("level-list")) {
drawable = new LevelListDrawable();
} else if (name.equals("layer-list")) {
drawable = new LayerDrawable();
} else if (name.equals("transition")) {
drawable = new TransitionDrawable();
} else if (name.equals("color")) {
drawable = new ColorDrawable();
} else if (name.equals("shape")) {
drawable = new GradientDrawable();
} else if (name.equals("scale")) {
drawable = new ScaleDrawable();
} else if (name.equals("clip")) {
drawable = new ClipDrawable();
} else if (name.equals("rotate")) {
drawable = new RotateDrawable();
} else if (name.equals("animation-list")) {
drawable = new AnimationDrawable();
} else if (name.equals("inset")) {
drawable = new InsetDrawable();
} else if (name.equals("bitmap")) {
drawable = new BitmapDrawable();
if (r != null) {
((BitmapDrawable) drawable).setDensityScale(r.getDisplayMetrics());
}
} else if (name.equals("nine-patch")) {
drawable = new NinePatchDrawable();
} else {
throw new XmlPullParserException(parser.getPositionDescription() +
": invalid drawable tag " + name);
}
drawable.inflate(r, parser, attrs);
return drawable;
}
/**
* Create a drawable from file path name.
*/
public static Drawable createFromPath(String pathName) {
if (pathName == null) {
return null;
}
Bitmap bm = BitmapFactory.decodeFile(pathName);
if (bm != null) {
return drawableFromBitmap(null, bm, null, null, pathName);
}
return null;
}
public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs)
throws XmlPullParserException, IOException {
TypedArray a = r.obtainAttributes(attrs, com.android.internal.R.styleable.Drawable);
inflateWithAttributes(r, parser, a, com.android.internal.R.styleable.Drawable_visible);
a.recycle();
}
void inflateWithAttributes(Resources r, XmlPullParser parser,
TypedArray attrs, int visibleAttr)
throws XmlPullParserException, IOException {
mVisible = attrs.getBoolean(visibleAttr, mVisible);
}
public static abstract class ConstantState {
public abstract Drawable newDrawable();
public abstract int getChangingConfigurations();
}
public ConstantState getConstantState() {
return null;
}
private static Drawable drawableFromBitmap(Resources res, Bitmap bm, byte[] np,
Rect pad, String srcName) {
if (np != null) {
return new NinePatchDrawable(bm, np, pad, srcName);
}
final BitmapDrawable drawable = new BitmapDrawable(bm);
if (res != null) {
drawable.setDensityScale(res.getDisplayMetrics());
}
return drawable;
}
}
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