/*
* 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.widget;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.view.View.OnFocusChangeListener;
/**
*
* Displays a list of tab labels representing each page in the parent's tab
* collection. The container object for this widget is
* {@link android.widget.TabHost TabHost}. When the user selects a tab, this
* object sends a message to the parent container, TabHost, to tell it to switch
* the displayed page. You typically won't use many methods directly on this
* object. The container TabHost is used to add labels, add the callback
* handler, and manage callbacks. You might call this object to iterate the list
* of tabs, or to tweak the layout of the tab list, but most methods should be
* called on the containing TabHost object.
*/
public class TabWidget extends LinearLayout implements OnFocusChangeListener {
private OnTabSelectionChanged mSelectionChangedListener;
private int mSelectedTab = 0;
private Drawable mBottomLeftStrip;
private Drawable mBottomRightStrip;
private boolean mStripMoved;
public TabWidget(Context context) {
this(context, null);
}
public TabWidget(Context context, AttributeSet attrs) {
this(context, attrs, com.android.internal.R.attr.tabWidgetStyle);
}
public TabWidget(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs);
initTabWidget();
TypedArray a =
context.obtainStyledAttributes(attrs, com.android.internal.R.styleable.TabWidget,
defStyle, 0);
a.recycle();
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
mStripMoved = true;
super.onSizeChanged(w, h, oldw, oldh);
}
private void initTabWidget() {
setOrientation(LinearLayout.HORIZONTAL);
mBottomLeftStrip = mContext.getResources().getDrawable(
com.android.internal.R.drawable.tab_bottom_left);
mBottomRightStrip = mContext.getResources().getDrawable(
com.android.internal.R.drawable.tab_bottom_right);
// Deal with focus, as we don't want the focus to go by default
// to a tab other than the current tab
setFocusable(true);
setOnFocusChangeListener(this);
}
@Override
public void childDrawableStateChanged(View child) {
if (child == getChildAt(mSelectedTab)) {
// To make sure that the bottom strip is redrawn
invalidate();
}
super.childDrawableStateChanged(child);
}
@Override
public void dispatchDraw(Canvas canvas) {
super.dispatchDraw(canvas);
View selectedChild = getChildAt(mSelectedTab);
mBottomLeftStrip.setState(selectedChild.getDrawableState());
mBottomRightStrip.setState(selectedChild.getDrawableState());
if (mStripMoved) {
Rect selBounds = new Rect(); // Bounds of the selected tab indicator
selBounds.left = selectedChild.getLeft();
selBounds.right = selectedChild.getRight();
final int myHeight = getHeight();
mBottomLeftStrip.setBounds(
Math.min(0, selBounds.left
- mBottomLeftStrip.getIntrinsicWidth()),
myHeight - mBottomLeftStrip.getIntrinsicHeight(),
selBounds.left,
getHeight());
mBottomRightStrip.setBounds(
selBounds.right,
myHeight - mBottomRightStrip.getIntrinsicHeight(),
Math.max(getWidth(),
selBounds.right + mBottomRightStrip.getIntrinsicWidth()),
myHeight);
mStripMoved = false;
}
mBottomLeftStrip.draw(canvas);
mBottomRightStrip.draw(canvas);
}
/**
* Sets the current tab.
* This method is used to bring a tab to the front of the Widget,
* and is used to post to the rest of the UI that a different tab
* has been brought to the foreground.
*
* Note, this is separate from the traditional "focus" that is
* employed from the view logic.
*
* For instance, if we have a list in a tabbed view, a user may be
* navigating up and down the list, moving the UI focus (orange
* highlighting) through the list items. The cursor movement does
* not effect the "selected" tab though, because what is being
* scrolled through is all on the same tab. The selected tab only
* changes when we navigate between tabs (moving from the list view
* to the next tabbed view, in this example).
*
* To move both the focus AND the selected tab at once, please use
* {@link #setCurrentTab}. Normally, the view logic takes care of
* adjusting the focus, so unless you're circumventing the UI,
* you'll probably just focus your interest here.
*
* @param index The tab that you want to indicate as the selected
* tab (tab brought to the front of the widget)
*
* @see #focusCurrentTab
*/
public void setCurrentTab(int index) {
if (index < 0 || index >= getChildCount()) {
return;
}
getChildAt(mSelectedTab).setSelected(false);
mSelectedTab = index;
getChildAt(mSelectedTab).setSelected(true);
mStripMoved = true;
}
/**
* Sets the current tab and focuses the UI on it.
* This method makes sure that the focused tab matches the selected
* tab, normally at {@link #setCurrentTab}. Normally this would not
* be an issue if we go through the UI, since the UI is responsible
* for calling TabWidget.onFocusChanged(), but in the case where we
* are selecting the tab programmatically, we'll need to make sure
* focus keeps up.
*
* @param index The tab that you want focused (highlighted in orange)
* and selected (tab brought to the front of the widget)
*
* @see #setCurrentTab
*/
public void focusCurrentTab(int index) {
final int oldTab = mSelectedTab;
// set the tab
setCurrentTab(index);
// change the focus if applicable.
if (oldTab != index) {
getChildAt(index).requestFocus();
}
}
@Override
public void setEnabled(boolean enabled) {
super.setEnabled(enabled);
int count = getChildCount();
for (int i=0; i<count; i++) {
View child = getChildAt(i);
child.setEnabled(enabled);
}
}
@Override
public void addView(View child) {
if (child.getLayoutParams() == null) {
final LinearLayout.LayoutParams lp = new LayoutParams(
0,
ViewGroup.LayoutParams.WRAP_CONTENT, 1);
lp.setMargins(0, 0, 0, 0);
child.setLayoutParams(lp);
}
// Ensure you can navigate to the tab with the keyboard, and you can touch it
child.setFocusable(true);
child.setClickable(true);
super.addView(child);
// TODO: detect this via geometry with a tabwidget listener rather
// than potentially interfere with the view's listener
child.setOnClickListener(new TabClickListener(getChildCount() - 1));
child.setOnFocusChangeListener(this);
}
/**
* Provides a way for {@link TabHost} to be notified that the user clicked on a tab indicator.
*/
void setTabSelectionListener(OnTabSelectionChanged listener) {
mSelectionChangedListener = listener;
}
public void onFocusChange(View v, boolean hasFocus) {
if (v == this && hasFocus) {
getChildAt(mSelectedTab).requestFocus();
return;
}
if (hasFocus) {
int i = 0;
while (i < getChildCount()) {
if (getChildAt(i) == v) {
setCurrentTab(i);
mSelectionChangedListener.onTabSelectionChanged(i, false);
break;
}
i++;
}
}
}
// registered with each tab indicator so we can notify tab host
private class TabClickListener implements OnClickListener {
private final int mTabIndex;
private TabClickListener(int tabIndex) {
mTabIndex = tabIndex;
}
public void onClick(View v) {
mSelectionChangedListener.onTabSelectionChanged(mTabIndex, true);
}
}
/**
* Let {@link TabHost} know that the user clicked on a tab indicator.
*/
static interface OnTabSelectionChanged {
/**
* Informs the TabHost which tab was selected. It also indicates
* if the tab was clicked/pressed or just focused into.
*
* @param tabIndex index of the tab that was selected
* @param clicked whether the selection changed due to a touch/click
* or due to focus entering the tab through navigation. Pass true
* if it was due to a press/click and false otherwise.
*/
void onTabSelectionChanged(int tabIndex, boolean clicked);
}
}
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