/*
* 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 com.android.internal.R;
import android.content.Context;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.os.Build;
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;
private Drawable mDividerDrawable;
private boolean mDrawBottomStrips = true;
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);
}
@Override
protected int getChildDrawingOrder(int childCount, int i) {
// Always draw the selected tab last, so that drop shadows are drawn
// in the correct z-order.
if (i == childCount - 1) {
return mSelectedTab;
} else if (i >= mSelectedTab) {
return i + 1;
} else {
return i;
}
}
private void initTabWidget() {
setOrientation(LinearLayout.HORIZONTAL);
mGroupFlags |= FLAG_USE_CHILD_DRAWING_ORDER;
final Context context = mContext;
final Resources resources = context.getResources();
if (context.getApplicationInfo().targetSdkVersion <= Build.VERSION_CODES.DONUT) {
// Donut apps get old color scheme
mBottomLeftStrip = resources.getDrawable(
com.android.internal.R.drawable.tab_bottom_left_v4);
mBottomRightStrip = resources.getDrawable(
com.android.internal.R.drawable.tab_bottom_right_v4);
} else {
// Use modern color scheme for Eclair and beyond
mBottomLeftStrip = resources.getDrawable(
com.android.internal.R.drawable.tab_bottom_left);
mBottomRightStrip = resources.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);
}
/**
* Returns the tab indicator view at the given index.
*
* @param index the zero-based index of the tab indicator view to return
* @return the tab indicator view at the given index
*/
public View getChildTabViewAt(int index) {
// If we are using dividers, then instead of tab views at 0, 1, 2, ...
// we have tab views at 0, 2, 4, ...
if (mDividerDrawable != null) {
index *= 2;
}
return getChildAt(index);
}
/**
* Returns the number of tab indicator views.
* @return the number of tab indicator views.
*/
public int getTabCount() {
int children = getChildCount();
// If we have dividers, then we will always have an odd number of
// children: 1, 3, 5, ... and we want to convert that sequence to
// this: 1, 2, 3, ...
if (mDividerDrawable != null) {
children = (children + 1) / 2;
}
return children;
}
/**
* Sets the drawable to use as a divider between the tab indicators.
* @param drawable the divider drawable
*/
public void setDividerDrawable(Drawable drawable) {
mDividerDrawable = drawable;
}
/**
* Sets the drawable to use as a divider between the tab indicators.
* @param resId the resource identifier of the drawable to use as a
* divider.
*/
public void setDividerDrawable(int resId) {
mDividerDrawable = mContext.getResources().getDrawable(resId);
}
/**
* Controls whether the bottom strips on the tab indicators are drawn or
* not. The default is to draw them. If the user specifies a custom
* view for the tab indicators, then the TabHost class calls this method
* to disable drawing of the bottom strips.
* @param drawBottomStrips true if the bottom strips should be drawn.
*/
void setDrawBottomStrips(boolean drawBottomStrips) {
mDrawBottomStrips = drawBottomStrips;
}
@Override
public void childDrawableStateChanged(View child) {
if (child == getChildTabViewAt(mSelectedTab)) {
// To make sure that the bottom strip is redrawn
invalidate();
}
super.childDrawableStateChanged(child);
}
@Override
public void dispatchDraw(Canvas canvas) {
super.dispatchDraw(canvas);
// If the user specified a custom view for the tab indicators, then
// do not draw the bottom strips.
if (!mDrawBottomStrips) {
// Skip drawing the bottom strips.
return;
}
View selectedChild = getChildTabViewAt(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 >= getTabCount()) {
return;
}
getChildTabViewAt(mSelectedTab).setSelected(false);
mSelectedTab = index;
getChildTabViewAt(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) {
getChildTabViewAt(index).requestFocus();
}
}
@Override
public void setEnabled(boolean enabled) {
super.setEnabled(enabled);
int count = getTabCount();
for (int i = 0; i < count; i++) {
View child = getChildTabViewAt(i);
child.setEnabled(enabled);
}
}
@Override
public void addView(View child) {
if (child.getLayoutParams() == null) {
final LinearLayout.LayoutParams lp = new LayoutParams(
0,
ViewGroup.LayoutParams.FILL_PARENT, 1.0f);
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);
// If we have dividers between the tabs and we already have at least one
// tab, then add a divider before adding the next tab.
if (mDividerDrawable != null && getTabCount() > 0) {
ImageView divider = new ImageView(mContext);
final LinearLayout.LayoutParams lp = new LayoutParams(
mDividerDrawable.getIntrinsicWidth(),
LayoutParams.FILL_PARENT);
lp.setMargins(0, 0, 0, 0);
divider.setLayoutParams(lp);
divider.setBackgroundDrawable(mDividerDrawable);
super.addView(divider);
}
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(getTabCount() - 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) {
getChildTabViewAt(mSelectedTab).requestFocus();
return;
}
if (hasFocus) {
int i = 0;
int numTabs = getTabCount();
while (i < numTabs) {
if (getChildTabViewAt(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);
}
}