private static final StringTAG ="NoPreloadViewPager";
private static final boolean DEBUG =false;
private static final boolean USE_CACHE =false;
private static final int DEFAULT_OFFSCREEN_PAGES =0;//默认是1
private static final int MAX_SETTLE_DURATION =600; // ms
static class ItemInfo {
Objectobject;
int position;
boolean scrolling;
}
private static final ComparatorCOMPARATOR =new Comparator(){
@Override
public int compare(ItemInfo lhs, ItemInfo rhs) {
return lhs.position - rhs.position;
}};
private static final InterpolatorsInterpolator =new Interpolator() {
public float getInterpolation(float t) {
// _o(t) = t * t * ((tension + 1) * t + tension)
// o(t) = _o(t - 1) + 1
t -=1.0f;
return t * t * t +1.0f;
}
};
private final ArrayListmItems =new ArrayList();
private PagerAdaptermAdapter;
private int mCurItem; // Index of currently displayed page.
private int mRestoredCurItem = -1;
private ParcelablemRestoredAdapterState =null;
private ClassLoadermRestoredClassLoader =null;
private ScrollermScroller;
private PagerObservermObserver;
private int mPageMargin;
private DrawablemMarginDrawable;
private int mChildWidthMeasureSpec;
private int mChildHeightMeasureSpec;
private boolean mInLayout;
private boolean mScrollingCacheEnabled;
private boolean mPopulatePending;
private boolean mScrolling;
private int mOffscreenPageLimit =DEFAULT_OFFSCREEN_PAGES;
private boolean mIsBeingDragged;
private boolean mIsUnableToDrag;
private int mTouchSlop;
private float mInitialMotionX;
/**
* Position of the last motion event.
*/
private float mLastMotionX;
private float mLastMotionY;
/**
* ID of the active pointer. This is used to retain consistency during
* drags/flings if multiple pointers are used.
*/
private int mActivePointerId =INVALID_POINTER;
/**
* Sentinel value for no current active pointer.
* Used by {@link #mActivePointerId}.
*/
private static final int INVALID_POINTER = -1;
/**
* Determines speed during touch scrolling
*/
private VelocityTrackermVelocityTracker;
private int mMinimumVelocity;
private int mMaximumVelocity;
private float mBaseLineFlingVelocity;
private float mFlingVelocityInfluence;
private boolean mFakeDragging;
private long mFakeDragBeginTime;
private EdgeEffectCompatmLeftEdge;
private EdgeEffectCompatmRightEdge;
private boolean mFirstLayout =true;
private OnPageChangeListenermOnPageChangeListener;
/**
* Indicates that the pager is in an idle, settled state. The current page
* is fully in view and no animation is in progress.
*/
public static final int SCROLL_STATE_IDLE =0;
/**
* Indicates that the pager is currently being dragged by the user.
*/
public static final int SCROLL_STATE_DRAGGING =1;
/**
* Indicates that the pager is in the process of settling to a final position.
*/
public static final int SCROLL_STATE_SETTLING =2;
private int mScrollState =SCROLL_STATE_IDLE;
/**
* Callback interface for responding to changing state of the selected page.
*/
public interface OnPageChangeListener {
/**
* This method will be invoked when the current page is scrolled, either as part
* of a programmatically initiated smooth scroll or a user initiated touch scroll.
*
* @param position Position index of the first page currently being displayed.
* Page position+1 will be visible if positionOffset is nonzero.
* @param positionOffset Value from [0, 1) indicating the offset from the page at position.
* @param positionOffsetPixels Value in pixels indicating the offset from position.
*/
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels);
/**
* This method will be invoked when a new page becomes selected. Animation is not
* necessarily complete.
*
* @param position Position index of the new selected page.
*/
public void onPageSelected(int position);
/**
* Called when the scroll state changes. Useful for discovering when the user
* begins dragging, when the pager is automatically settling to the current page,
* or when it is fully stopped/idle.
*
* @param state The new scroll state.
*
*/
public void onPageScrollStateChanged(int state);
}
/**
*
*/
public static class SimpleOnPageChangeListenerimplements OnPageChangeListener {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
// This space for rent
}
@Override
public void onPageSelected(int position) {
// This space for rent
}
@Override
public void onPageScrollStateChanged(int state) {
// This space for rent
}
}
public NoPreloadViewPager(Context context) {
super(context);
initViewPager();
}
public NoPreloadViewPager(Context context, AttributeSet attrs) {
super(context, attrs);
initViewPager();
}
void initViewPager() {
setWillNotDraw(false);
setDescendantFocusability(FOCUS_AFTER_DESCENDANTS);
setFocusable(true);
final Context context = getContext();
mScroller =new Scroller(context, sInterpolator);
final ViewConfiguration configuration = ViewConfiguration.get(context);
mTouchSlop = ViewConfigurationCompat.getScaledPagingTouchSlop(configuration);
mMinimumVelocity = configuration.getScaledMinimumFlingVelocity();
mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
mLeftEdge =new EdgeEffectCompat(context);
mRightEdge =new EdgeEffectCompat(context);
float density = context.getResources().getDisplayMetrics().density;
mBaseLineFlingVelocity =2500.0f * density;
mFlingVelocityInfluence =0.4f;
}
private void setScrollState(int newState) {
if (mScrollState == newState) {
return;
}
mScrollState = newState;
if (mOnPageChangeListener !=null) {
mOnPageChangeListener.onPageScrollStateChanged(newState);
}
}
public void setAdapter(PagerAdapter adapter) {
if (mAdapter !=null) {
// mAdapter.unregisterDataSetObserver(mObserver);
mAdapter.startUpdate(this);
for (int i =0; i
final ItemInfo ii =mItems.get(i);
mAdapter.destroyItem(this, ii.position, ii.object);
}
mAdapter.finishUpdate(this);
mItems.clear();
removeAllViews();
mCurItem =0;
scrollTo(0, 0);
}
mAdapter = adapter;
if (mAdapter !=null) {
if (mObserver ==null) {
mObserver =new PagerObserver();
}
// mAdapter.registerDataSetObserver(mObserver);
mPopulatePending =false;
if (mRestoredCurItem >=0) {
mAdapter.restoreState(mRestoredAdapterState, mRestoredClassLoader);
setCurrentItemInternal(mRestoredCurItem, false, true);
mRestoredCurItem = -1;
mRestoredAdapterState =null;
mRestoredClassLoader =null;
}else {
populate();
}
}
}
public PagerAdaptergetAdapter() {
return mAdapter;
}
/**
* Set the currently selected page. If the ViewPager has already been through its first
* layout there will be a smooth animated transition between the current item and the
* specified item.
*
* @param item Item index to select
*/
public void setCurrentItem(int item) {
mPopulatePending =false;
setCurrentItemInternal(item, !mFirstLayout, false);
}
/**
* Set the currently selected page.
*
* @param item Item index to select
* @param smoothScroll True to smoothly scroll to the new item, false to transition immediately
*/
public void setCurrentItem(int item, boolean smoothScroll) {
mPopulatePending =false;
setCurrentItemInternal(item, smoothScroll, false);
}
public int getCurrentItem() {
return mCurItem;
}
void setCurrentItemInternal(int item, boolean smoothScroll, boolean always) {
setCurrentItemInternal(item, smoothScroll, always, 0);
}
void setCurrentItemInternal(int item, boolean smoothScroll, boolean always, int velocity) {
if (mAdapter ==null ||mAdapter.getCount() <=0) {
setScrollingCacheEnabled(false);
return;
}
if (!always &&mCurItem == item &&mItems.size() !=0) {
setScrollingCacheEnabled(false);
return;
}
if (item <0) {
item =0;
}else if (item >=mAdapter.getCount()) {
item =mAdapter.getCount() -1;
}
final int pageLimit =mOffscreenPageLimit;
if (item > (mCurItem + pageLimit) || item < (mCurItem - pageLimit)) {
// We are doing a jump by more than one page. To avoid
// glitches, we want to keep all current pages in the view
// until the scroll ends.
for (int i=0; i
mItems.get(i).scrolling =true;
}
}
final boolean dispatchSelected =mCurItem != item;
mCurItem = item;
populate();
final int destX = (getWidth() +mPageMargin) * item;
if (smoothScroll) {
smoothScrollTo(destX, 0, velocity);
if (dispatchSelected &&mOnPageChangeListener !=null) {
mOnPageChangeListener.onPageSelected(item);
}
}else {
if (dispatchSelected &&mOnPageChangeListener !=null) {
mOnPageChangeListener.onPageSelected(item);
}
completeScroll();
scrollTo(destX, 0);
}
}
public void setOnPageChangeListener(OnPageChangeListener listener) {
mOnPageChangeListener = listener;
}
/**
* Returns the number of pages that will be retained to either side of the
* current page in the view hierarchy in an idle state. Defaults to 1.
*
* @return How many pages will be kept offscreen on either side
* @see #setOffscreenPageLimit(int)
*/
public int getOffscreenPageLimit() {
return mOffscreenPageLimit;
}
/**
* Set the number of pages that should be retained to either side of the
* current page in the view hierarchy in an idle state. Pages beyond this
* limit will be recreated from the adapter when needed.
*
* <p>This is offered as an optimization. If you know in advance the number
* of pages you will need to support or have lazy-loading mechanisms in place
* on your pages, tweaking this setting can have benefits in perceived smoothness
* of paging animations and interaction. If you have a small number of pages (3-4)
* that you can keep active all at once, less time will be spent in layout for
* newly created view subtrees as the user pages back and forth.
*
* <p>You should keep this limit low, especially if your pages have complex layouts.
* This setting defaults to 1.
*
* @param limit How many pages will be kept offscreen in an idle state.
*/
public void setOffscreenPageLimit(int limit) {
if (limit
Log.w(TAG, "Requested offscreen page limit " + limit +" too small; defaulting to " +
DEFAULT_OFFSCREEN_PAGES);
limit =DEFAULT_OFFSCREEN_PAGES;
}
if (limit !=mOffscreenPageLimit) {
mOffscreenPageLimit = limit;
populate();
}
}
/**
* Set the margin between pages.
*
* @param marginPixels Distance between adjacent pages in pixels
* @see #getPageMargin()
* @see #setPageMarginDrawable(android.graphics.drawable.Drawable)
* @see #setPageMarginDrawable(int)
*/
public void setPageMargin(int marginPixels) {
final int oldMargin =mPageMargin;
mPageMargin = marginPixels;
final int width = getWidth();
recomputeScrollPosition(width, width, marginPixels, oldMargin);
requestLayout();
}
/**
* Return the margin between pages.
*
* @return The size of the margin in pixels
*/
public int getPageMargin() {
return mPageMargin;
}
/**
* Set a drawable that will be used to fill the margin between pages.
*
* @param d Drawable to display between pages
*/
public void setPageMarginDrawable(Drawable d) {
mMarginDrawable = d;
if (d !=null) refreshDrawableState();
setWillNotDraw(d ==null);
invalidate();
}
/**
* Set a drawable that will be used to fill the margin between pages.
*
* @param resId Resource ID of a drawable to display between pages
*/
public void setPageMarginDrawable(int resId) {
setPageMarginDrawable(getContext().getResources().getDrawable(resId));
}
@Override
protected boolean verifyDrawable(Drawable who) {
return super.verifyDrawable(who) || who ==mMarginDrawable;
}
@Override
protected void drawableStateChanged() {
super.drawableStateChanged();
final Drawable d =mMarginDrawable;
if (d !=null && d.isStateful()) {
d.setState(getDrawableState());
}
}
// We want the duration of the page snap animation to be influenced by the distance that
// the screen has to travel, however, we don't want this duration to be effected in a
// purely linear fashion. Instead, we use this method to moderate the effect that the distance
// of travel has on the overall snap duration.
float distanceInfluenceForSnapDuration(float f) {
f -=0.5f; // center the values about 0.
f *=0.3f * Math.PI /2.0f;
return (float) Math.sin(f);
}
/**
* Like {@link android.view.View#scrollBy}, but scroll smoothly instead of immediately.
*
* @param x the number of pixels to scroll by on the X axis
* @param y the number of pixels to scroll by on the Y axis
*/
void smoothScrollTo(int x, int y) {
smoothScrollTo(x, y, 0);
}
/**
* Like {@link android.view.View#scrollBy}, but scroll smoothly instead of immediately.
*
* @param x the number of pixels to scroll by on the X axis
* @param y the number of pixels to scroll by on the Y axis
* @param velocity the velocity associated with a fling, if applicable. (0 otherwise)
*/
void smoothScrollTo(int x, int y, int velocity) {
if (getChildCount() ==0) {
// Nothing to do.
setScrollingCacheEnabled(false);
return;
}
int sx = getScrollX();
int sy = getScrollY();
int dx = x - sx;
int dy = y - sy;
if (dx ==0 && dy ==0) {
completeScroll();
setScrollState(SCROLL_STATE_IDLE);
return;
}
setScrollingCacheEnabled(true);
mScrolling =true;
setScrollState(SCROLL_STATE_SETTLING);
final float pageDelta = (float) Math.abs(dx) / (getWidth() +mPageMargin);
int duration = (int) (pageDelta *100);
velocity = Math.abs(velocity);
if (velocity >0) {
duration += (duration / (velocity /mBaseLineFlingVelocity)) *mFlingVelocityInfluence;
}else {
duration +=100;
}
duration = Math.min(duration, MAX_SETTLE_DURATION);
mScroller.startScroll(sx, sy, dx, dy, duration);
invalidate();
}
void addNewItem(int position, int index) {
ItemInfo ii =new ItemInfo();
ii.position = position;
ii.object =mAdapter.instantiateItem(this, position);
if (index <0) {
mItems.add(ii);
}else {
mItems.add(index, ii);
}
}
void dataSetChanged() {
// This method only gets called if our observer is attached, so mAdapter is non-null.
boolean needPopulate =mItems.size() <3 &&mItems.size()
int newCurrItem = -1;
for (int i =0; i
final ItemInfo ii =mItems.get(i);
final int newPos =mAdapter.getItemPosition(ii.object);
if (newPos == PagerAdapter.POSITION_UNCHANGED) {
continue;
}
if (newPos == PagerAdapter.POSITION_NONE) {
mItems.remove(i);
i--;
mAdapter.destroyItem(this, ii.position, ii.object);
needPopulate =true;
if (mCurItem == ii.position) {
// Keep the current item in the valid range
newCurrItem = Math.max(0, Math.min(mCurItem, mAdapter.getCount() -1));
}
continue;
}
if (ii.position != newPos) {
if (ii.position ==mCurItem) {
// Our current item changed position. Follow it.
newCurrItem = newPos;
}
ii.position = newPos;
needPopulate =true;
}
}
Collections.sort(mItems, COMPARATOR);
if (newCurrItem >=0) {
// TODO This currently causes a jump.
setCurrentItemInternal(newCurrItem, false, true);
needPopulate =true;
}
if (needPopulate) {
populate();
requestLayout();
}
}
void populate() {
if (mAdapter ==null) {
return;
}
// Bail now if we are waiting to populate. This is to hold off
// on creating views from the time the user releases their finger to
// fling to a new position until we have finished the scroll to
// that position, avoiding glitches from happening at that point.
if (mPopulatePending) {
if (DEBUG) Log.i(TAG, "populate is pending, skipping for now...");
return;
}
// Also, don't populate until we are attached to a window. This is to
// avoid trying to populate before we have restored our view hierarchy
// state and conflicting with what is restored.
if (getWindowToken() ==null) {
return;
}
mAdapter.startUpdate(this);
final int pageLimit =mOffscreenPageLimit;
final int startPos = Math.max(0, mCurItem - pageLimit);
final int N =mAdapter.getCount();
final int endPos = Math.min(N-1, mCurItem + pageLimit);
if (DEBUG) Log.v(TAG, "populating: startPos=" + startPos +" endPos=" + endPos);
// Add and remove pages in the existing list.
int lastPos = -1;
for (int i=0; i
ItemInfo ii =mItems.get(i);
if ((ii.position < startPos || ii.position > endPos) && !ii.scrolling) {
if (DEBUG) Log.i(TAG, "removing: " + ii.position +" @ " + i);
mItems.remove(i);
i--;
mAdapter.destroyItem(this, ii.position, ii.object);
}else if (lastPos < endPos && ii.position > startPos) {
// The next item is outside of our range, but we have a gap
// between it and the last item where we want to have a page
// shown. Fill in the gap.
lastPos++;
if (lastPos < startPos) {
lastPos = startPos;
}
while (lastPos <= endPos && lastPos < ii.position) {
if (DEBUG) Log.i(TAG, "inserting: " + lastPos +" @ " + i);
addNewItem(lastPos, i);
lastPos++;
i++;
}
}
lastPos = ii.position;
}
// Add any new pages we need at the end.
lastPos =mItems.size() >0 ?mItems.get(mItems.size()-1).position : -1;
if (lastPos < endPos) {
lastPos++;
lastPos = lastPos > startPos ? lastPos : startPos;
while (lastPos <= endPos) {
if (DEBUG) Log.i(TAG, "appending: " + lastPos);
addNewItem(lastPos, -1);
lastPos++;
}
}
if (DEBUG) {
Log.i(TAG, "Current page list:");
for (int i=0; i
Log.i(TAG, "#" + i +": page " +mItems.get(i).position);
}
}
ItemInfo curItem =null;
for (int i=0; i
if (mItems.get(i).position ==mCurItem) {
curItem =mItems.get(i);
break;
}
}
mAdapter.setPrimaryItem(this, mCurItem, curItem !=null ? curItem.object :null);
mAdapter.finishUpdate(this);
if (hasFocus()) {
View currentFocused = findFocus();
ItemInfo ii = currentFocused !=null ? infoForAnyChild(currentFocused) :null;
if (ii ==null || ii.position !=mCurItem) {
for (int i=0; i
View child = getChildAt(i);
ii = infoForChild(child);
if (ii !=null && ii.position ==mCurItem) {
if (child.requestFocus(FOCUS_FORWARD)) {
break;
}
}
}
}
}
}
public static class SavedStateextends BaseSavedState {
int position;
ParcelableadapterState;
ClassLoaderloader;
public SavedState(Parcelable superState) {
super(superState);
}
@Override
public void writeToParcel(Parcel out, int flags) {
super.writeToParcel(out, flags);
out.writeInt(position);
out.writeParcelable(adapterState, flags);
}
@Override
public StringtoString() {
return "FragmentPager.SavedState{"
+ Integer.toHexString(System.identityHashCode(this))
+" position=" +position +"}";
}
public static final CreatorCREATOR
= ParcelableCompat.newCreator(new ParcelableCompatCreatorCallbacks() {
@Override
public SavedStatecreateFromParcel(Parcel in, ClassLoader loader) {
return new SavedState(in, loader);
}
@Override
public SavedState[]newArray(int size) {
return new SavedState[size];
}
});
SavedState(Parcel in, ClassLoader loader) {
super(in);
if (loader ==null) {
loader = getClass().getClassLoader();
}
position = in.readInt();
adapterState = in.readParcelable(loader);
this.loader = loader;
}
}
@Override
public ParcelableonSaveInstanceState() {
Parcelable superState =super.onSaveInstanceState();
SavedState ss =new SavedState(superState);
ss.position =mCurItem;
if (mAdapter !=null) {
ss.adapterState =mAdapter.saveState();
}
return ss;
}
@Override
public void onRestoreInstanceState(Parcelable state) {
if (!(stateinstanceof SavedState)) {
super.onRestoreInstanceState(state);
return;
}
SavedState ss = (SavedState)state;
super.onRestoreInstanceState(ss.getSuperState());
if (mAdapter !=null) {
mAdapter.restoreState(ss.adapterState, ss.loader);
setCurrentItemInternal(ss.position, false, true);
}else {
mRestoredCurItem = ss.position;
mRestoredAdapterState = ss.adapterState;
mRestoredClassLoader = ss.loader;
}
}
@Override
public void addView(View child, int index, LayoutParams params) {
if (mInLayout) {
addViewInLayout(child, index, params);
child.measure(mChildWidthMeasureSpec, mChildHeightMeasureSpec);
}else {
super.addView(child, index, params);
}
if (USE_CACHE) {
if (child.getVisibility() !=GONE) {
child.setDrawingCacheEnabled(mScrollingCacheEnabled);
}else {
child.setDrawingCacheEnabled(false);
}
}
}
ItemInfoinfoForChild(View child) {
for (int i=0; i
ItemInfo ii =mItems.get(i);
if (mAdapter.isViewFromObject(child, ii.object)) {
return ii;
}
}
return null;
}
ItemInfoinfoForAnyChild(View child) {
ViewParent parent;
while ((parent=child.getParent()) !=this) {
if (parent ==null || !(parentinstanceof View)) {
return null;
}
child = (View)parent;
}
return infoForChild(child);
}
@Override
protected void onAttachedToWindow() {
super.onAttachedToWindow();
mFirstLayout =true;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// For simple implementation, or internal size is always 0.
// We depend on the container to specify the layout size of
// our view. We can't really know what it is since we will be
// adding and removing different arbitrary views and do not
// want the layout to change as this happens.
setMeasuredDimension(getDefaultSize(0, widthMeasureSpec),
getDefaultSize(0, heightMeasureSpec));
// Children are just made to fill our space.
mChildWidthMeasureSpec = MeasureSpec.makeMeasureSpec(getMeasuredWidth() -
getPaddingLeft() - getPaddingRight(), MeasureSpec.EXACTLY);
mChildHeightMeasureSpec = MeasureSpec.makeMeasureSpec(getMeasuredHeight() -
getPaddingTop() - getPaddingBottom(), MeasureSpec.EXACTLY);
// Make sure we have created all fragments that we need to have shown.
mInLayout =true;
populate();
mInLayout =false;
// Make sure all children have been properly measured.
final int size = getChildCount();
for (int i =0; i < size; ++i) {
final View child = getChildAt(i);
if (child.getVisibility() !=GONE) {
if (DEBUG) Log.v(TAG, "Measuring #" + i +" " + child
+": " +mChildWidthMeasureSpec);
child.measure(mChildWidthMeasureSpec, mChildHeightMeasureSpec);
}
}
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
// Make sure scroll position is set correctly.
if (w != oldw) {
recomputeScrollPosition(w, oldw, mPageMargin, mPageMargin);
}
}
private void recomputeScrollPosition(int width, int oldWidth, int margin, int oldMargin) {
final int widthWithMargin = width + margin;
if (oldWidth >0) {
final int oldScrollPos = getScrollX();
final int oldwwm = oldWidth + oldMargin;
final int oldScrollItem = oldScrollPos / oldwwm;
final float scrollOffset = (float) (oldScrollPos % oldwwm) / oldwwm;
final int scrollPos = (int) ((oldScrollItem + scrollOffset) * widthWithMargin);
scrollTo(scrollPos, getScrollY());
if (!mScroller.isFinished()) {
// We now return to your regularly scheduled scroll, already in progress.
final int newDuration =mScroller.getDuration() -mScroller.timePassed();
mScroller.startScroll(scrollPos, 0, mCurItem * widthWithMargin, 0, newDuration);
}
}else {
int scrollPos =mCurItem * widthWithMargin;
if (scrollPos != getScrollX()) {
completeScroll();
scrollTo(scrollPos, getScrollY());
}
}
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
mInLayout =true;
populate();
mInLayout =false;
final int count = getChildCount();
final int width = r-l;
for (int i =0; i < count; i++) {
View child = getChildAt(i);
ItemInfo ii;
if (child.getVisibility() !=GONE && (ii=infoForChild(child)) !=null) {
int loff = (width +mPageMargin) * ii.position;
int childLeft = getPaddingLeft() + loff;
int childTop = getPaddingTop();
if (DEBUG) Log.v(TAG, "Positioning #" + i +" " + child +" f=" + ii.object
+":" + childLeft +"," + childTop +" " + child.getMeasuredWidth()
+"x" + child.getMeasuredHeight());
child.layout(childLeft, childTop,
childLeft + child.getMeasuredWidth(),
childTop + child.getMeasuredHeight());
}
}
mFirstLayout =false;
}
@Override
public void computeScroll() {
if (DEBUG) Log.i(TAG, "computeScroll: finished=" +mScroller.isFinished());
if (!mScroller.isFinished()) {
if (mScroller.computeScrollOffset()) {
if (DEBUG) Log.i(TAG, "computeScroll: still scrolling");
int oldX = getScrollX();
int oldY = getScrollY();
int x =mScroller.getCurrX();
int y =mScroller.getCurrY();
if (oldX != x || oldY != y) {
scrollTo(x, y);
}
if (mOnPageChangeListener !=null) {
final int widthWithMargin = getWidth() +mPageMargin;
final int position = x / widthWithMargin;
final int offsetPixels = x % widthWithMargin;
final float offset = (float) offsetPixels / widthWithMargin;
mOnPageChangeListener.onPageScrolled(position, offset, offsetPixels);
}
// Keep on drawing until the animation has finished.
invalidate();
return;
}
}
// Done with scroll, clean up state.
completeScroll();
}
private void completeScroll() {
boolean needPopulate =mScrolling;
if (needPopulate) {
// Done with scroll, no longer want to cache view drawing.
setScrollingCacheEnabled(false);
mScroller.abortAnimation();
int oldX = getScrollX();
int oldY = getScrollY();
int x =mScroller.getCurrX();
int y =mScroller.getCurrY();
if (oldX != x || oldY != y) {
scrollTo(x, y);
}
setScrollState(SCROLL_STATE_IDLE);
}
mPopulatePending =false;
mScrolling =false;
for (int i=0; i
ItemInfo ii =mItems.get(i);
if (ii.scrolling) {
needPopulate =true;
ii.scrolling =false;
}
}
if (needPopulate) {
populate();
}
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
/*
* This method JUST determines whether we want to intercept the motion.
* If we return true, onMotionEvent will be called and we do the actual
* scrolling there.
*/
final int action = ev.getAction() & MotionEventCompat.ACTION_MASK;
// Always take care of the touch gesture being complete.
if (action == MotionEvent.ACTION_CANCEL || action == MotionEvent.ACTION_UP) {
// Release the drag.
if (DEBUG) Log.v(TAG, "Intercept done!");
mIsBeingDragged =false;
mIsUnableToDrag =false;
mActivePointerId =INVALID_POINTER;
return false;
}
// Nothing more to do here if we have decided whether or not we
// are dragging.
if (action != MotionEvent.ACTION_DOWN) {
if (mIsBeingDragged) {
if (DEBUG) Log.v(TAG, "Intercept returning true!");
return true;
}
if (mIsUnableToDrag) {
if (DEBUG) Log.v(TAG, "Intercept returning false!");
return false;
}
}
switch (action) {
case MotionEvent.ACTION_MOVE: {
/*
* mIsBeingDragged == false, otherwise the shortcut would have caught it. Check
* whether the user has moved far enough from his original down touch.
*/
/*
* Locally do absolute value. mLastMotionY is set to the y value
* of the down event.
*/
final int activePointerId =mActivePointerId;
if (activePointerId ==INVALID_POINTER) {
// If we don't have a valid id, the touch down wasn't on content.
break;
}
final int pointerIndex = MotionEventCompat.findPointerIndex(ev, activePointerId);
final float x = MotionEventCompat.getX(ev, pointerIndex);
final float dx = x -mLastMotionX;
final float xDiff = Math.abs(dx);
final float y = MotionEventCompat.getY(ev, pointerIndex);
final float yDiff = Math.abs(y -mLastMotionY);
final int scrollX = getScrollX();
final boolean atEdge = (dx >0 && scrollX ==0) || (dx <0 &&mAdapter !=null &&
scrollX >= (mAdapter.getCount() -1) * getWidth() -1);
if (DEBUG) Log.v(TAG, "Moved x to " + x +"," + y +" diff=" + xDiff +"," + yDiff);
if (canScroll(this, false, (int) dx, (int) x, (int) y)) {
// Nested view has scrollable area under this point. Let it be handled there.
mInitialMotionX =mLastMotionX = x;
mLastMotionY = y;
return false;
}
if (xDiff >mTouchSlop && xDiff > yDiff) {
if (DEBUG) Log.v(TAG, "Starting drag!");
mIsBeingDragged =true;
setScrollState(SCROLL_STATE_DRAGGING);
mLastMotionX = x;
setScrollingCacheEnabled(true);
}else {
if (yDiff >mTouchSlop) {
// The finger has moved enough in the vertical
// direction to be counted as a drag... abort
// any attempt to drag horizontally, to work correctly
// with children that have scrolling containers.
if (DEBUG) Log.v(TAG, "Starting unable to drag!");
mIsUnableToDrag =true;
}
}
break;
}
case MotionEvent.ACTION_DOWN: {
/*
* Remember location of down touch.
* ACTION_DOWN always refers to pointer index 0.
*/
mLastMotionX =mInitialMotionX = ev.getX();
mLastMotionY = ev.getY();
mActivePointerId = MotionEventCompat.getPointerId(ev, 0);
if (mScrollState ==SCROLL_STATE_SETTLING) {
// Let the user 'catch' the pager as it animates.
mIsBeingDragged =true;
mIsUnableToDrag =false;
setScrollState(SCROLL_STATE_DRAGGING);
}else {
completeScroll();
mIsBeingDragged =false;
mIsUnableToDrag =false;
}
if (DEBUG) Log.v(TAG, "Down at " +mLastMotionX +"," +mLastMotionY
+" mIsBeingDragged=" +mIsBeingDragged
+"mIsUnableToDrag=" +mIsUnableToDrag);
break;
}
case MotionEventCompat.ACTION_POINTER_UP:
onSecondaryPointerUp(ev);
break;
}
/*
* The only time we want to intercept motion events is if we are in the
* drag mode.
*/
return mIsBeingDragged;
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
if (mFakeDragging) {
// A fake drag is in progress already, ignore this real one
// but still eat the touch events.
// (It is likely that the user is multi-touching the screen.)
return true;
}
if (ev.getAction() == MotionEvent.ACTION_DOWN && ev.getEdgeFlags() !=0) {
// Don't handle edge touches immediately -- they may actually belong to one of our
// descendants.
return false;
}
if (mAdapter ==null ||mAdapter.getCount() ==0) {
// Nothing to present or scroll; nothing to touch.
return false;
}
if (mVelocityTracker ==null) {
mVelocityTracker = VelocityTracker.obtain();
}
mVelocityTracker.addMovement(ev);
final int action = ev.getAction();
boolean needsInvalidate =false;
switch (action & MotionEventCompat.ACTION_MASK) {
case MotionEvent.ACTION_DOWN: {
/*
* If being flinged and user touches, stop the fling. isFinished
* will be false if being flinged.
*/
completeScroll();
// Remember where the motion event started
mLastMotionX =mInitialMotionX = ev.getX();
mActivePointerId = MotionEventCompat.getPointerId(ev, 0);
break;
}
case MotionEvent.ACTION_MOVE:
if (!mIsBeingDragged) {
final int pointerIndex = MotionEventCompat.findPointerIndex(ev, mActivePointerId);
final float x = MotionEventCompat.getX(ev, pointerIndex);
final float xDiff = Math.abs(x -mLastMotionX);
final float y = MotionEventCompat.getY(ev, pointerIndex);
final float yDiff = Math.abs(y -mLastMotionY);
if (DEBUG) Log.v(TAG, "Moved x to " + x +"," + y +" diff=" + xDiff +"," + yDiff);
if (xDiff >mTouchSlop && xDiff > yDiff) {
if (DEBUG) Log.v(TAG, "Starting drag!");
mIsBeingDragged =true;
mLastMotionX = x;
setScrollState(SCROLL_STATE_DRAGGING);
setScrollingCacheEnabled(true);
}
}
if (mIsBeingDragged) {
// Scroll to follow the motion event
final int activePointerIndex = MotionEventCompat.findPointerIndex(
ev, mActivePointerId);
final float x = MotionEventCompat.getX(ev, activePointerIndex);
final float deltaX =mLastMotionX - x;
mLastMotionX = x;
float oldScrollX = getScrollX();
float scrollX = oldScrollX + deltaX;
final int width = getWidth();
final int widthWithMargin = width +mPageMargin;
final int lastItemIndex =mAdapter.getCount() -1;
final float leftBound = Math.max(0, (mCurItem -1) * widthWithMargin);
final float rightBound =
Math.min(mCurItem +1, lastItemIndex) * widthWithMargin;
if (scrollX < leftBound) {
if (leftBound ==0) {
float over = -scrollX;
needsInvalidate =mLeftEdge.onPull(over / width);
}
scrollX = leftBound;
}else if (scrollX > rightBound) {
if (rightBound == lastItemIndex * widthWithMargin) {
float over = scrollX - rightBound;
needsInvalidate =mRightEdge.onPull(over / width);
}
scrollX = rightBound;
}
// Don't lose the rounded component
mLastMotionX += scrollX - (int) scrollX;
scrollTo((int) scrollX, getScrollY());
if (mOnPageChangeListener !=null) {
final int position = (int) scrollX / widthWithMargin;
final int positionOffsetPixels = (int) scrollX % widthWithMargin;
final float positionOffset = (float) positionOffsetPixels / widthWithMargin;
mOnPageChangeListener.onPageScrolled(position, positionOffset,
positionOffsetPixels);
}
}
break;
case MotionEvent.ACTION_UP:
if (mIsBeingDragged) {
final VelocityTracker velocityTracker =mVelocityTracker;
velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
int initialVelocity = (int) VelocityTrackerCompat.getXVelocity(
velocityTracker, mActivePointerId);
mPopulatePending =true;
final int widthWithMargin = getWidth() +mPageMargin;
final int scrollX = getScrollX();
final int currentPage = scrollX / widthWithMargin;
int nextPage = initialVelocity >0 ? currentPage : currentPage +1;
setCurrentItemInternal(nextPage, true, true, initialVelocity);
mActivePointerId =INVALID_POINTER;
endDrag();
needsInvalidate =mLeftEdge.onRelease() |mRightEdge.onRelease();
}
break;
case MotionEvent.ACTION_CANCEL:
if (mIsBeingDragged) {
setCurrentItemInternal(mCurItem, true, true);
mActivePointerId =INVALID_POINTER;
endDrag();
needsInvalidate =mLeftEdge.onRelease() |mRightEdge.onRelease();
}
break;
case MotionEventCompat.ACTION_POINTER_DOWN: {
final int index = MotionEventCompat.getActionIndex(ev);
final float x = MotionEventCompat.getX(ev, index);
mLastMotionX = x;
mActivePointerId = MotionEventCompat.getPointerId(ev, index);
break;
}
case MotionEventCompat.ACTION_POINTER_UP:
onSecondaryPointerUp(ev);
mLastMotionX = MotionEventCompat.getX(ev,
MotionEventCompat.findPointerIndex(ev, mActivePointerId));
break;
}
if (needsInvalidate) {
invalidate();
}
return true;
}
@Override
public void draw(Canvas canvas) {
super.draw(canvas);
boolean needsInvalidate =false;
final int overScrollMode = ViewCompat.getOverScrollMode(this);
if (overScrollMode == ViewCompat.OVER_SCROLL_ALWAYS ||
(overScrollMode == ViewCompat.OVER_SCROLL_IF_CONTENT_SCROLLS &&
mAdapter !=null &&mAdapter.getCount() >1)) {
if (!mLeftEdge.isFinished()) {
final int restoreCount = canvas.save();
final int height = getHeight() - getPaddingTop() - getPaddingBottom();
canvas.rotate(270);
canvas.translate(-height + getPaddingTop(), 0);
mLeftEdge.setSize(height, getWidth());
needsInvalidate |=mLeftEdge.draw(canvas);
canvas.restoreToCount(restoreCount);
}
if (!mRightEdge.isFinished()) {
final int restoreCount = canvas.save();
final int width = getWidth();
final int height = getHeight() - getPaddingTop() - getPaddingBottom();
final int itemCount =mAdapter !=null ?mAdapter.getCount() :1;
canvas.rotate(90);
canvas.translate(-getPaddingTop(),
-itemCount * (width +mPageMargin) +mPageMargin);
mRightEdge.setSize(height, width);
needsInvalidate |=mRightEdge.draw(canvas);
canvas.restoreToCount(restoreCount);
}
}else {
mLeftEdge.finish();
mRightEdge.finish();
}
if (needsInvalidate) {
// Keep animating
invalidate();
}
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
// Draw the margin drawable if needed.
if (mPageMargin >0 &&mMarginDrawable !=null) {
final int scrollX = getScrollX();
final int width = getWidth();
final int offset = scrollX % (width +mPageMargin);
if (offset !=0) {
// Pages fit completely when settled; we only need to draw when in between
final int left = scrollX - offset + width;
mMarginDrawable.setBounds(left, 0, left +mPageMargin, getHeight());
mMarginDrawable.draw(canvas);
}
}
}
/**
* Start a fake drag of the pager.
*
* <p>A fake drag can be useful if you want to synchronize the motion of the ViewPager
* with the touch scrolling of another view, while still letting the ViewPager
* control the snapping motion and fling behavior. (e.g. parallax-scrolling tabs.)
* Call {@link #fakeDragBy(float)} to simulate the actual drag motion. Call
* {@link #endFakeDrag()} to complete the fake drag and fling as necessary.
*
* <p>During a fake drag the ViewPager will ignore all touch events. If a real drag
* is already in progress, this method will return false.
*
* @return true if the fake drag began successfully, false if it could not be started.
*
* @see #fakeDragBy(float)
* @see #endFakeDrag()
*/
public boolean beginFakeDrag() {
if (mIsBeingDragged) {
return false;
}
mFakeDragging =true;
setScrollState(SCROLL_STATE_DRAGGING);
mInitialMotionX =mLastMotionX =0;
if (mVelocityTracker ==null) {
mVelocityTracker = VelocityTracker.obtain();
}else {
mVelocityTracker.clear();
}
final long time = SystemClock.uptimeMillis();
final MotionEvent ev = MotionEvent.obtain(time, time, MotionEvent.ACTION_DOWN, 0, 0, 0);
mVelocityTracker.addMovement(ev);
ev.recycle();
mFakeDragBeginTime = time;
return true;
}
/**
* End a fake drag of the pager.
*
* @see #beginFakeDrag()
* @see #fakeDragBy(float)
*/
public void endFakeDrag() {
if (!mFakeDragging) {
throw new IllegalStateException("No fake drag in progress. Call beginFakeDrag first.");
}
final VelocityTracker velocityTracker =mVelocityTracker;
velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
int initialVelocity = (int)VelocityTrackerCompat.getYVelocity(
velocityTracker, mActivePointerId);
mPopulatePending =true;
if ((Math.abs(initialVelocity) >mMinimumVelocity)
|| Math.abs(mInitialMotionX-mLastMotionX) >= (getWidth()/3)) {
if (mLastMotionX >mInitialMotionX) {
setCurrentItemInternal(mCurItem-1, true, true);
}else {
setCurrentItemInternal(mCurItem+1, true, true);
}
}else {
setCurrentItemInternal(mCurItem, true, true);
}
endDrag();
mFakeDragging =false;
}
/**
* Fake drag by an offset in pixels. You must have called {@link #beginFakeDrag()} first.
*
* @param xOffset Offset in pixels to drag by.
* @see #beginFakeDrag()
* @see #endFakeDrag()
*/
public void fakeDragBy(float xOffset) {
if (!mFakeDragging) {
throw new IllegalStateException("No fake drag in progress. Call beginFakeDrag first.");
}
mLastMotionX += xOffset;
float scrollX = getScrollX() - xOffset;
final int width = getWidth();
final int widthWithMargin = width +mPageMargin;
final float leftBound = Math.max(0, (mCurItem -1) * widthWithMargin);
final float rightBound =
Math.min(mCurItem +1, mAdapter.getCount() -1) * widthWithMargin;
if (scrollX < leftBound) {
scrollX = leftBound;
}else if (scrollX > rightBound) {
scrollX = rightBound;
}
// Don't lose the rounded component
mLastMotionX += scrollX - (int) scrollX;
scrollTo((int) scrollX, getScrollY());
if (mOnPageChangeListener !=null) {
final int position = (int) scrollX / widthWithMargin;
final int positionOffsetPixels = (int) scrollX % widthWithMargin;
final float positionOffset = (float) positionOffsetPixels / widthWithMargin;
mOnPageChangeListener.onPageScrolled(position, positionOffset,
positionOffsetPixels);
}
// Synthesize an event for the VelocityTracker.
final long time = SystemClock.uptimeMillis();
final MotionEvent ev = MotionEvent.obtain(mFakeDragBeginTime, time, MotionEvent.ACTION_MOVE,
mLastMotionX, 0, 0);
mVelocityTracker.addMovement(ev);
ev.recycle();
}
/**
* Returns true if a fake drag is in progress.
*
* @return true if currently in a fake drag, false otherwise.
*
* @see #beginFakeDrag()
* @see #fakeDragBy(float)
* @see #endFakeDrag()
*/
public boolean isFakeDragging() {
return mFakeDragging;
}
private void onSecondaryPointerUp(MotionEvent ev) {
final int pointerIndex = MotionEventCompat.getActionIndex(ev);
final int pointerId = MotionEventCompat.getPointerId(ev, pointerIndex);
if (pointerId ==mActivePointerId) {
// This was our active pointer going up. Choose a new
// active pointer and adjust accordingly.
final int newPointerIndex = pointerIndex ==0 ?1 :0;
mLastMotionX = MotionEventCompat.getX(ev, newPointerIndex);
mActivePointerId = MotionEventCompat.getPointerId(ev, newPointerIndex);
if (mVelocityTracker !=null) {
mVelocityTracker.clear();
}
}
}
private void endDrag() {
mIsBeingDragged =false;
mIsUnableToDrag =false;
if (mVelocityTracker !=null) {
mVelocityTracker.recycle();
mVelocityTracker =null;
}
}
private void setScrollingCacheEnabled(boolean enabled) {
if (mScrollingCacheEnabled != enabled) {
mScrollingCacheEnabled = enabled;
if (USE_CACHE) {
final int size = getChildCount();
for (int i =0; i < size; ++i) {
final View child = getChildAt(i);
if (child.getVisibility() !=GONE) {
child.setDrawingCacheEnabled(enabled);
}
}
}
}
}
/**
* Tests scrollability within child views of v given a delta of dx.
*
* @param v View to test for horizontal scrollability
* @param checkV Whether the view v passed should itself be checked for scrollability (true),
* or just its children (false).
* @param dx Delta scrolled in pixels
* @param x X coordinate of the active touch point
* @param y Y coordinate of the active touch point
* @return true if child views of v can be scrolled by delta of dx.
*/
protected boolean canScroll(View v, boolean checkV, int dx, int x, int y) {
if (vinstanceof ViewGroup) {
final ViewGroup group = (ViewGroup) v;
final int scrollX = v.getScrollX();
final int scrollY = v.getScrollY();
final int count = group.getChildCount();
// Count backwards - let topmost views consume scroll distance first.
for (int i = count -1; i >=0; i--) {
// TODO: Add versioned support here for transformed views.
// This will not work for transformed views in Honeycomb+
final View child = group.getChildAt(i);
if (x + scrollX >= child.getLeft() && x + scrollX < child.getRight() &&
y + scrollY >= child.getTop() && y + scrollY < child.getBottom() &&
canScroll(child, true, dx, x + scrollX - child.getLeft(),
y + scrollY - child.getTop())) {
return true;
}
}
}
return checkV && ViewCompat.canScrollHorizontally(v, -dx);
}
@Override
public boolean dispatchKeyEvent(KeyEvent event) {
// Let the focused view and/or our descendants get the key first
return super.dispatchKeyEvent(event) || executeKeyEvent(event);
}
/**
* You can call this function yourself to have the scroll view perform
* scrolling from a key event, just as if the event had been dispatched to
* it by the view hierarchy.
*
* @param event The key event to execute.
* @return Return true if the event was handled, else false.
*/
public boolean executeKeyEvent(KeyEvent event) {
boolean handled =false;
if (event.getAction() == KeyEvent.ACTION_DOWN) {
switch (event.getKeyCode()) {
case KeyEvent.KEYCODE_DPAD_LEFT:
handled = arrowScroll(FOCUS_LEFT);
break;
case KeyEvent.KEYCODE_DPAD_RIGHT:
handled = arrowScroll(FOCUS_RIGHT);
break;
case KeyEvent.KEYCODE_TAB:
if (event.hasNoModifiers()) {
handled = arrowScroll(FOCUS_FORWARD);
}else if (event.hasModifiers(KeyEvent.META_SHIFT_ON)) {
handled = arrowScroll(FOCUS_BACKWARD);
}
break;
}
}
return handled;
}
public boolean arrowScroll(int direction) {
View currentFocused = findFocus();
if (currentFocused ==this) currentFocused =null;
boolean handled =false;
View nextFocused = FocusFinder.getInstance().findNextFocus(this, currentFocused,
direction);
if (nextFocused !=null && nextFocused != currentFocused) {
if (direction == View.FOCUS_LEFT) {
// If there is nothing to the left, or this is causing us to
// jump to the right, then what we really want to do is page left.
if (currentFocused !=null && nextFocused.getLeft() >= currentFocused.getLeft()) {
handled = pageLeft();
}else {
handled = nextFocused.requestFocus();
}
}else if (direction == View.FOCUS_RIGHT) {
// If there is nothing to the right, or this is causing us to
// jump to the left, then what we really want to do is page right.
if (currentFocused !=null && nextFocused.getLeft() <= currentFocused.getLeft()) {
handled = pageRight();
}else {
handled = nextFocused.requestFocus();
}
}
}else if (direction ==FOCUS_LEFT || direction ==FOCUS_BACKWARD) {
// Trying to move left and nothing there; try to page.
handled = pageLeft();
}else if (direction ==FOCUS_RIGHT || direction ==FOCUS_FORWARD) {
// Trying to move right and nothing there; try to page.
handled = pageRight();
}
if (handled) {
playSoundEffect(SoundEffectConstants.getContantForFocusDirection(direction));
}
return handled;
}
boolean pageLeft() {
if (mCurItem >0) {
setCurrentItem(mCurItem-1, true);
return true;
}
return false;
}
boolean pageRight() {
if (mAdapter !=null &&mCurItem < (mAdapter.getCount()-1)) {
setCurrentItem(mCurItem+1, true);
return true;
}
return false;
}
/**
* We only want the current page that is being shown to be focusable.
*/
@Override
public void addFocusables(ArrayList views, int direction, int focusableMode) {
final int focusableCount = views.size();
final int descendantFocusability = getDescendantFocusability();
if (descendantFocusability !=FOCUS_BLOCK_DESCENDANTS) {
for (int i =0; i < getChildCount(); i++) {
final View child = getChildAt(i);
if (child.getVisibility() ==VISIBLE) {
ItemInfo ii = infoForChild(child);
if (ii !=null && ii.position ==mCurItem) {
child.addFocusables(views, direction, focusableMode);
}
}
}
}
// we add ourselves (if focusable) in all cases except for when we are
// FOCUS_AFTER_DESCENDANTS and there are some descendants focusable. this is
// to avoid the focus search finding layouts when a more precise search
// among the focusable children would be more interesting.
if (
descendantFocusability !=FOCUS_AFTER_DESCENDANTS ||
// No focusable descendants
(focusableCount == views.size())) {
// Note that we can't call the superclass here, because it will
// add all views in. So we need to do the same thing View does.
if (!isFocusable()) {
return;
}
if ((focusableMode &FOCUSABLES_TOUCH_MODE) ==FOCUSABLES_TOUCH_MODE &&
isInTouchMode() && !isFocusableInTouchMode()) {
return;
}
if (views !=null) {
views.add(this);
}
}
}
/**
* We only want the current page that is being shown to be touchable.
*/
@Override
public void addTouchables(ArrayList views) {
// Note that we don't call super.addTouchables(), which means that
// we don't call View.addTouchables(). This is okay because a ViewPager
// is itself not touchable.
for (int i =0; i < getChildCount(); i++) {
final View child = getChildAt(i);
if (child.getVisibility() ==VISIBLE) {
ItemInfo ii = infoForChild(child);
if (ii !=null && ii.position ==mCurItem) {
child.addTouchables(views);
}
}
}
}
/**
* We only want the current page that is being shown to be focusable.
*/
@Override
protected boolean onRequestFocusInDescendants(int direction,
Rect previouslyFocusedRect) {
int index;
int increment;
int end;
int count = getChildCount();
if ((direction &FOCUS_FORWARD) !=0) {
index =0;
increment =1;
end = count;
}else {
index = count -1;
increment = -1;
end = -1;
}
for (int i = index; i != end; i += increment) {
View child = getChildAt(i);
if (child.getVisibility() ==VISIBLE) {
ItemInfo ii = infoForChild(child);
if (ii !=null && ii.position ==mCurItem) {
if (child.requestFocus(direction, previouslyFocusedRect)) {
return true;
}
}
}
}
return false;
}
@Override
public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) {
// ViewPagers should only report accessibility info for the current page,
// otherwise things get very confusing.
// TODO: Should this note something about the paging container?
final int childCount = getChildCount();
for (int i =0; i < childCount; i++) {
final View child = getChildAt(i);
if (child.getVisibility() ==VISIBLE) {
final ItemInfo ii = infoForChild(child);
if (ii !=null && ii.position ==mCurItem &&
child.dispatchPopulateAccessibilityEvent(event)) {
return true;
}
}
}
return false;
}
private class PagerObserverextends DataSetObserver {
@Override
public void onChanged() {
dataSetChanged();
}
@Override
public void onInvalidated() {
dataSetChanged();
}
}
}
