() {
@Override
public SavedState createFromParcel(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 Parcelable onSaveInstanceState() {
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 (!(state instanceof 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);
}
}
}
ItemInfo infoForChild(View child) {
for (int i = 0; i < mItems.size(); i++) {
ItemInfo ii = mItems.get(i);
if (mAdapter.isViewFromObject(child, ii.object)) {
return ii;
}
}
return null;
}
ItemInfo infoForAnyChild(View child) {
ViewParent parent;
while ((parent = child.getParent()) != this) {
if (parent == null || !(parent instanceof 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 < mItems.size(); 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();
// 澧炲姞杈硅窛鍒ゆ柇
int currentPage = scrollX / widthWithMargin;
int leftPageScorll = scrollX % widthWithMargin;
int nextPage = currentPage;
float chargeVelocity = initialVelocity;
if (chargeVelocity > 0) {
// 鍚戝彸
if (widthWithMargin - leftPageScorll > mPagerNextMarginPixels) {
nextPage = currentPage;
} else {
nextPage = currentPage + 1;
}
} else {
// 鍚戝乏
if (leftPageScorll > mPagerNextMarginPixels) {
nextPage = currentPage + 1;
} else {
nextPage = currentPage;
}
}
// nextPage = chargeVelocity > 0 ? currentPage
// : currentPage + 1;
// Log.d(TAG, "initialVelocity:" + initialVelocity
// + ", currentPage: " + (scrollX / widthWithMargin)
// + ", widthWithMargin: " + widthWithMargin
// + ", scrollX: " + scrollX + ", chargeVelocity: "
// + chargeVelocity + ", nextPage: " + nextPage);
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.
*
*
* 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.
*
*
* 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() {
Log.d(TAG, "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;
Log.d(TAG,
"initialVelocity: " + initialVelocity
+ ", Math.abs(mInitialMotionX - mLastMotionX): "
+ Math.abs(mInitialMotionX - mLastMotionX));
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 (v instanceof 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 (KeyEventCompat.hasNoModifiers(event)) {
handled = arrowScroll(FOCUS_FORWARD);
} else if (KeyEventCompat.hasModifiers(event,
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;
}
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