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Apache License
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package com.jeremyfeinstein.slidingmenu.lib; //w w w. j a v a 2 s . c o m import java.util.ArrayList; import java.util.List; import android.content.Context; import android.graphics.Canvas; import android.graphics.Rect; import android.os.Build; import android.util.AttributeSet; import android.util.FloatMath; import android.util.Log; import android.view.FocusFinder; import android.view.KeyEvent; import android.view.MotionEvent; import android.view.SoundEffectConstants; import android.view.VelocityTracker; import android.view.View; import android.view.ViewConfiguration; import android.view.ViewGroup; import android.view.animation.Interpolator; import android.widget.Scroller; import com.jeremyfeinstein.slidingmenu.lib.SlidingMenu.OnClosedListener; import com.jeremyfeinstein.slidingmenu.lib.SlidingMenu.OnOpenedListener; //import com.jeremyfeinstein.slidingmenu.lib.SlidingMenu.OnCloseListener; //import com.jeremyfeinstein.slidingmenu.lib.SlidingMenu.OnOpenListener; public class CustomViewAbove extends ViewGroup { private static final String TAG = "CustomViewAbove"; private static final boolean DEBUG = false; private static final boolean USE_CACHE = false; private static final int MAX_SETTLE_DURATION = 600; // ms private static final int MIN_DISTANCE_FOR_FLING = 25; // dips private static final Interpolator sInterpolator = new Interpolator() { public float getInterpolation(float t) { t -= 1.0f; return t * t * t * t * t + 1.0f; } }; private View mContent; private int mCurItem; private Scroller mScroller; private boolean mScrollingCacheEnabled; private boolean mScrolling; 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. */ protected 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 */ protected VelocityTracker mVelocityTracker; private int mMinimumVelocity; protected int mMaximumVelocity; private int mFlingDistance; private CustomViewBehind mViewBehind; // private int mMode; private boolean mEnabled = true; private OnPageChangeListener mOnPageChangeListener; private OnPageChangeListener mInternalPageChangeListener; // private OnCloseListener mCloseListener; // private OnOpenListener mOpenListener; private OnClosedListener mClosedListener; private OnOpenedListener mOpenedListener; private List<View> mIgnoredViews = new ArrayList<View>(); // 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); } /** * Simple implementation of the {@link OnPageChangeListener} interface with * stub implementations of each method. Extend this if you do not intend to * override every method of {@link OnPageChangeListener}. */ public static class SimpleOnPageChangeListener implements OnPageChangeListener { public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { // This space for rent } public void onPageSelected(int position) { // This space for rent } public void onPageScrollStateChanged(int state) { // This space for rent } } public CustomViewAbove(Context context) { this(context, null); } public CustomViewAbove(Context context, AttributeSet attrs) { super(context, attrs); initCustomViewAbove(); } void initCustomViewAbove() { setWillNotDraw(false); setDescendantFocusability(FOCUS_AFTER_DESCENDANTS); setFocusable(true); final Context context = getContext(); mScroller = new Scroller(context, sInterpolator); final ViewConfiguration configuration = ViewConfiguration.get(context); mTouchSlop = configuration.getScaledPagingTouchSlop(); mMinimumVelocity = configuration.getScaledMinimumFlingVelocity(); mMaximumVelocity = configuration.getScaledMaximumFlingVelocity(); setInternalPageChangeListener(new SimpleOnPageChangeListener() { public void onPageSelected(int position) { if (mViewBehind != null) { switch (position) { case 0: case 2: mViewBehind.setChildrenEnabled(true); break; case 1: mViewBehind.setChildrenEnabled(false); break; } } } }); final float density = context.getResources().getDisplayMetrics().density; mFlingDistance = (int) (MIN_DISTANCE_FOR_FLING * density); } /** * Set the currently selected page. If the CustomViewPager 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) { setCurrentItemInternal(item, true, 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) { 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 (!always && mCurItem == item) { setScrollingCacheEnabled(false); return; } item = mViewBehind.getMenuPage(item); final boolean dispatchSelected = mCurItem != item; mCurItem = item; final int destX = getDestScrollX(mCurItem); if (dispatchSelected && mOnPageChangeListener != null) { mOnPageChangeListener.onPageSelected(item); } if (dispatchSelected && mInternalPageChangeListener != null) { mInternalPageChangeListener.onPageSelected(item); } if (smoothScroll) { smoothScrollTo(destX, 0, velocity); } else { completeScroll(); scrollTo(destX, 0); } } /** * Set a listener that will be invoked whenever the page changes or is * incrementally scrolled. See {@link OnPageChangeListener}. * * @param listener * Listener to set */ public void setOnPageChangeListener(OnPageChangeListener listener) { mOnPageChangeListener = listener; } /* * public void setOnOpenListener(OnOpenListener l) { mOpenListener = l; } * * public void setOnCloseListener(OnCloseListener l) { mCloseListener = l; } */ public void setOnOpenedListener(OnOpenedListener l) { mOpenedListener = l; } public void setOnClosedListener(OnClosedListener l) { mClosedListener = l; } /** * Set a separate OnPageChangeListener for internal use by the support * library. * * @param listener * Listener to set * @return The old listener that was set, if any. */ OnPageChangeListener setInternalPageChangeListener( OnPageChangeListener listener) { OnPageChangeListener oldListener = mInternalPageChangeListener; mInternalPageChangeListener = listener; return oldListener; } public void addIgnoredView(View v) { if (!mIgnoredViews.contains(v)) { mIgnoredViews.add(v); } } public void removeIgnoredView(View v) { mIgnoredViews.remove(v); } public void clearIgnoredViews() { mIgnoredViews.clear(); } // 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) FloatMath.sin(f); } public int getDestScrollX(int page) { switch (page) { case 0: case 2: return mViewBehind.getMenuLeft(mContent, page); case 1: return mContent.getLeft(); } return 0; } private int getLeftBound() { return mViewBehind.getAbsLeftBound(mContent); } private int getRightBound() { return mViewBehind.getAbsRightBound(mContent); } public int getContentLeft() { return mContent.getLeft() + mContent.getPaddingLeft(); } public boolean isMenuOpen() { return mCurItem == 0 || mCurItem == 2; } private boolean isInIgnoredView(MotionEvent ev) { Rect rect = new Rect(); for (View v : mIgnoredViews) { v.getHitRect(rect); if (rect.contains((int) ev.getX(), (int) ev.getY())) return true; } return false; } public int getBehindWidth() { if (mViewBehind == null) { return 0; } else { return mViewBehind.getBehindWidth(); } } public int getChildWidth(int i) { switch (i) { case 0: return getBehindWidth(); case 1: return mContent.getWidth(); default: return 0; } } public boolean isSlidingEnabled() { return mEnabled; } public void setSlidingEnabled(boolean b) { mEnabled = b; } /** * Like {@link 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 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(); if (isMenuOpen()) { if (mOpenedListener != null) mOpenedListener.onOpened(); } else { if (mClosedListener != null) mClosedListener.onClosed(); } return; } setScrollingCacheEnabled(true); mScrolling = true; final int width = getBehindWidth(); final int halfWidth = width / 2; final float distanceRatio = Math.min(1f, 1.0f * Math.abs(dx) / width); final float distance = halfWidth + halfWidth * distanceInfluenceForSnapDuration(distanceRatio); int duration = 0; velocity = Math.abs(velocity); if (velocity > 0) { duration = 4 * Math.round(1000 * Math.abs(distance / velocity)); } else { final float pageDelta = (float) Math.abs(dx) / width; duration = (int) ((pageDelta + 1) * 100); duration = MAX_SETTLE_DURATION; } duration = Math.min(duration, MAX_SETTLE_DURATION); mScroller.startScroll(sx, sy, dx, dy, duration); invalidate(); } public void setContent(View v) { if (mContent != null) this.removeView(mContent); mContent = v; addView(mContent); } public View getContent() { return mContent; } public void setCustomViewBehind(CustomViewBehind cvb) { mViewBehind = cvb; } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { int width = getDefaultSize(0, widthMeasureSpec); int height = getDefaultSize(0, heightMeasureSpec); setMeasuredDimension(width, height); final int contentWidth = getChildMeasureSpec(widthMeasureSpec, 0, width); final int contentHeight = getChildMeasureSpec(heightMeasureSpec, 0, height); mContent.measure(contentWidth, contentHeight); } @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) { // [ChrisJ] - This fixes the onConfiguration change for orientation // issue.. // maybe worth having a look why the recomputeScroll pos is screwing // up? completeScroll(); scrollTo(getDestScrollX(mCurItem), getScrollY()); } } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { final int width = r - l; final int height = b - t; mContent.layout(0, 0, width, height); } public void setAboveOffset(int i) { // RelativeLayout.LayoutParams params = // ((RelativeLayout.LayoutParams)mContent.getLayoutParams()); // params.setMargins(i, params.topMargin, params.rightMargin, // params.bottomMargin); mContent.setPadding(i, mContent.getPaddingTop(), mContent.getPaddingRight(), mContent.getPaddingBottom()); } @Override public void computeScroll() { if (!mScroller.isFinished()) { if (mScroller.computeScrollOffset()) { int oldX = getScrollX(); int oldY = getScrollY(); int x = mScroller.getCurrX(); int y = mScroller.getCurrY(); if (oldX != x || oldY != y) { scrollTo(x, y); pageScrolled(x); } // Keep on drawing until the animation has finished. invalidate(); return; } } // Done with scroll, clean up state. completeScroll(); } private void pageScrolled(int xpos) { final int widthWithMargin = getWidth(); final int position = xpos / widthWithMargin; final int offsetPixels = xpos % widthWithMargin; final float offset = (float) offsetPixels / widthWithMargin; onPageScrolled(position, offset, offsetPixels); } /** * 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. If you override this method you must call through to the * superclass implementation (e.g. super.onPageScrolled(position, offset, * offsetPixels)) before onPageScrolled returns. * * @param position * Position index of the first page currently being displayed. * Page position+1 will be visible if positionOffset is nonzero. * @param offset * Value from [0, 1) indicating the offset from the page at * position. * @param offsetPixels * Value in pixels indicating the offset from position. */ protected void onPageScrolled(int position, float offset, int offsetPixels) { if (mOnPageChangeListener != null) { mOnPageChangeListener .onPageScrolled(position, offset, offsetPixels); } if (mInternalPageChangeListener != null) { mInternalPageChangeListener.onPageScrolled(position, offset, offsetPixels); } } 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); } if (isMenuOpen()) { if (mOpenedListener != null) mOpenedListener.onOpened(); } else { if (mClosedListener != null) mClosedListener.onClosed(); } } mScrolling = false; } protected int mTouchMode = SlidingMenu.TOUCHMODE_MARGIN; public void setTouchMode(int i) { mTouchMode = i; } public int getTouchMode() { return mTouchMode; } private boolean thisTouchAllowed(MotionEvent ev) { int x = (int) (ev.getX() + mScrollX); if (isMenuOpen()) { return mViewBehind.menuOpenTouchAllowed(mContent, mCurItem, x); } else { switch (mTouchMode) { case SlidingMenu.TOUCHMODE_FULLSCREEN: return !isInIgnoredView(ev); case SlidingMenu.TOUCHMODE_NONE: return false; case SlidingMenu.TOUCHMODE_MARGIN: return mViewBehind.marginTouchAllowed(mContent, x); } } return false; } private boolean thisSlideAllowed(float dx) { boolean allowed = false; if (isMenuOpen()) { allowed = mViewBehind.menuOpenSlideAllowed(dx); } else { allowed = mViewBehind.menuClosedSlideAllowed(dx); } if (DEBUG) Log.v(TAG, "this slide allowed " + allowed + " dx: " + dx); return allowed; } private int getPointerIndex(MotionEvent ev, int id) { int activePointerIndex = ev.findPointerIndex(id); if (activePointerIndex == -1) mActivePointerId = INVALID_POINTER; return activePointerIndex; } private boolean mQuickReturn = false; @Override public boolean onInterceptTouchEvent(MotionEvent ev) { if (!mEnabled) return false; final int action = ev.getAction() & MotionEvent.ACTION_MASK; if (DEBUG) if (action == MotionEvent.ACTION_DOWN) Log.v(TAG, "Received ACTION_DOWN"); if (action == MotionEvent.ACTION_CANCEL || action == MotionEvent.ACTION_UP || (action != MotionEvent.ACTION_DOWN && mIsUnableToDrag)) { endDrag(); return false; } switch (action) { case MotionEvent.ACTION_MOVE: determineDrag(ev); break; case MotionEvent.ACTION_DOWN: int index = ev.getActionIndex(); mActivePointerId = ev.getPointerId(index); if (mActivePointerId == INVALID_POINTER) break; mLastMotionX = mInitialMotionX = ev.getX(index); mLastMotionY = ev.getY(index); if (thisTouchAllowed(ev)) { mIsBeingDragged = false; mIsUnableToDrag = false; if (isMenuOpen() && mViewBehind.menuTouchInQuickReturn(mContent, mCurItem, ev.getX() + mScrollX)) { mQuickReturn = true; } } else { mIsUnableToDrag = true; } break; case MotionEvent.ACTION_POINTER_UP: onSecondaryPointerUp(ev); break; } if (!mIsBeingDragged) { if (mVelocityTracker == null) { mVelocityTracker = VelocityTracker.obtain(); } mVelocityTracker.addMovement(ev); } return mIsBeingDragged || mQuickReturn; } @Override public boolean onTouchEvent(MotionEvent ev) { if (!mEnabled) return false; if (!mIsBeingDragged && !thisTouchAllowed(ev)) return false; // if (!mIsBeingDragged && !mQuickReturn) // return false; final int action = ev.getAction(); if (mVelocityTracker == null) { mVelocityTracker = VelocityTracker.obtain(); } mVelocityTracker.addMovement(ev); switch (action & MotionEvent.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 int index = ev.getActionIndex(); mActivePointerId = ev.getPointerId(index); mLastMotionX = mInitialMotionX = ev.getX(); break; case MotionEvent.ACTION_MOVE: if (!mIsBeingDragged) { determineDrag(ev); if (mIsUnableToDrag) return false; } if (mIsBeingDragged) { // Scroll to follow the motion event final int activePointerIndex = getPointerIndex(ev, mActivePointerId); if (mActivePointerId == INVALID_POINTER) break; final float x = ev.getX(activePointerIndex); final float deltaX = mLastMotionX - x; mLastMotionX = x; float oldScrollX = getScrollX(); float scrollX = oldScrollX + deltaX; final float leftBound = getLeftBound(); final float rightBound = getRightBound(); 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()); pageScrolled((int) scrollX); } break; case MotionEvent.ACTION_UP: if (mIsBeingDragged) { final VelocityTracker velocityTracker = mVelocityTracker; velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity); int initialVelocity = (int) mVelocityTracker .getXVelocity(mActivePointerId); final int scrollX = getScrollX(); // final int widthWithMargin = getWidth(); // final float pageOffset = (float) (scrollX % widthWithMargin) // / widthWithMargin; // TODO test this. should get better flinging behavior final float pageOffset = (float) (scrollX - getDestScrollX(mCurItem)) / getBehindWidth(); final int activePointerIndex = getPointerIndex(ev, mActivePointerId); if (mActivePointerId != INVALID_POINTER) { final float x = ev.getX(activePointerIndex); final int totalDelta = (int) (x - mInitialMotionX); int nextPage = determineTargetPage(pageOffset, initialVelocity, totalDelta); setCurrentItemInternal(nextPage, true, true, initialVelocity); } else { setCurrentItemInternal(mCurItem, true, true, initialVelocity); } mActivePointerId = INVALID_POINTER; endDrag(); } else if (mQuickReturn && mViewBehind.menuTouchInQuickReturn(mContent, mCurItem, ev.getX() + mScrollX)) { // close the menu setCurrentItem(1); endDrag(); } break; case MotionEvent.ACTION_CANCEL: if (mIsBeingDragged) { setCurrentItemInternal(mCurItem, true, true); mActivePointerId = INVALID_POINTER; endDrag(); } break; case MotionEvent.ACTION_POINTER_DOWN: { final int indexx = ev.getActionIndex(); mLastMotionX = ev.getX(indexx); mActivePointerId = ev.getPointerId(indexx); break; } case MotionEvent.ACTION_POINTER_UP: onSecondaryPointerUp(ev); int pointerIndex = getPointerIndex(ev, mActivePointerId); if (mActivePointerId == INVALID_POINTER) break; mLastMotionX = ev.getX(pointerIndex); break; } return true; } private void determineDrag(MotionEvent ev) { final int activePointerId = mActivePointerId; final int pointerIndex = getPointerIndex(ev, activePointerId); if (activePointerId == INVALID_POINTER) return; final float x = ev.getX(pointerIndex); final float dx = x - mLastMotionX; final float xDiff = Math.abs(dx); final float y = ev.getY(pointerIndex); final float dy = y - mLastMotionY; final float yDiff = Math.abs(dy); if (xDiff > (isMenuOpen() ? mTouchSlop / 2 : mTouchSlop) && xDiff > yDiff && thisSlideAllowed(dx)) { startDrag(); mLastMotionX = x; mLastMotionY = y; setScrollingCacheEnabled(true); // TODO add back in touch slop check } else if (xDiff > mTouchSlop) { mIsUnableToDrag = true; } } @Override public void scrollTo(int x, int y) { super.scrollTo(x, y); mScrollX = x; mViewBehind.scrollBehindTo(mContent, x, y); ((SlidingMenu) getParent()).manageLayers(getPercentOpen()); } private int determineTargetPage(float pageOffset, int velocity, int deltaX) { int targetPage = mCurItem; if (Math.abs(deltaX) > mFlingDistance && Math.abs(velocity) > mMinimumVelocity) { if (velocity > 0 && deltaX > 0) { targetPage -= 1; } else if (velocity < 0 && deltaX < 0) { targetPage += 1; } } else { targetPage = (int) Math.round(mCurItem + pageOffset); } return targetPage; } protected float getPercentOpen() { return Math.abs(mScrollX - mContent.getLeft()) / getBehindWidth(); } @Override protected void dispatchDraw(Canvas canvas) { super.dispatchDraw(canvas); // Draw the margin drawable if needed. mViewBehind.drawShadow(mContent, canvas); mViewBehind.drawFade(mContent, canvas, getPercentOpen()); mViewBehind.drawSelector(mContent, canvas, getPercentOpen()); } // variables for drawing private float mScrollX = 0.0f; private void onSecondaryPointerUp(MotionEvent ev) { if (DEBUG) Log.v(TAG, "onSecondaryPointerUp called"); final int pointerIndex = ev.getActionIndex(); final int pointerId = ev.getPointerId(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 = ev.getX(newPointerIndex); mActivePointerId = ev.getPointerId(newPointerIndex); if (mVelocityTracker != null) { mVelocityTracker.clear(); } } } private void startDrag() { mIsBeingDragged = true; mQuickReturn = false; } private void endDrag() { mQuickReturn = false; mIsBeingDragged = false; mIsUnableToDrag = false; mActivePointerId = INVALID_POINTER; 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--) { 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 && v.canScrollHorizontally(-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 (Build.VERSION.SDK_INT >= 11) { // The focus finder had a bug handling FOCUS_FORWARD and // FOCUS_BACKWARD // before Android 3.0. Ignore the tab key on those devices. 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) { 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 (mCurItem < 1) { setCurrentItem(mCurItem + 1, true); return true; } return false; } }