on*methods are invoked on siginficant events and several
+ * accessor methods are expected to provide the ViewDragHelper with more information
+ * about the state of the parent view upon request. The callback also makes decisions
+ * governing the range and draggability of child views.
+ */
+ public static abstract class Callback {
+ /**
+ * Called when the drag state changes. See the STATE_* constants
+ * for more information.
+ *
+ * @param state The new drag state
+ *
+ * @see #STATE_IDLE
+ * @see #STATE_DRAGGING
+ * @see #STATE_SETTLING
+ */
+ public void onViewDragStateChanged(int state) {}
+ /**
+ * Called when the captured view's position changes as the result of a drag or settle.
+ *
+ * @param changedView View whose position changed
+ * @param left New X coordinate of the left edge of the view
+ * @param top New Y coordinate of the top edge of the view
+ * @param dx Change in X position from the last call
+ * @param dy Change in Y position from the last call
+ */
+ public void onViewPositionChanged(View changedView, int left, int top, int dx, int dy) {}
+ /**
+ * Called when a child view is captured for dragging or settling. The ID of the pointer
+ * currently dragging the captured view is supplied. If activePointerId is
+ * identified as {@link #INVALID_POINTER} the capture is programmatic instead of
+ * pointer-initiated.
+ *
+ * @param capturedChild Child view that was captured
+ * @param activePointerId Pointer id tracking the child capture
+ */
+ public void onViewCaptured(View capturedChild, int activePointerId) {}
+ /**
+ * Called when the child view is no longer being actively dragged.
+ * The fling velocity is also supplied, if relevant. The velocity values may
+ * be clamped to system minimums or maximums.
+ *
+ * Calling code may decide to fling or otherwise release the view to let it
+ * settle into place. It should do so using {@link #settleCapturedViewAt(int, int)}
+ * or {@link #flingCapturedView(int, int, int, int)}. If the Callback invokes
+ * one of these methods, the ViewDragHelper will enter {@link #STATE_SETTLING}
+ * and the view capture will not fully end until it comes to a complete stop.
+ * If neither of these methods is invoked before onViewReleased returns,
+ * the view will stop in place and the ViewDragHelper will return to
+ * {@link #STATE_IDLE}.
index
+ */
+ public int getOrderedChildIndex(int index) {
+ return index;
+ }
+ /**
+ * Return the magnitude of a draggable child view's horizontal range of motion in pixels.
+ * This method should return 0 for views that cannot move horizontally.
+ *
+ * @param child Child view to check
+ * @return range of horizontal motion in pixels
+ */
+ public int getViewHorizontalDragRange(View child) {
+ return 0;
+ }
+ /**
+ * Return the magnitude of a draggable child view's vertical range of motion in pixels.
+ * This method should return 0 for views that cannot move vertically.
+ *
+ * @param child Child view to check
+ * @return range of vertical motion in pixels
+ */
+ public int getViewVerticalDragRange(View child) {
+ return 0;
+ }
+ /**
+ * Called when the user's input indicates that they want to capture the given child view
+ * with the pointer indicated by pointerId. The callback should return true if the user
+ * is permitted to drag the given view with the indicated pointer.
+ *
+ * ViewDragHelper may call this method multiple times for the same view even if + * the view is already captured; this indicates that a new pointer is trying to take + * control of the view.
+ * + *If this method returns true, a call to {@link #onViewCaptured(android.view.View, int)} + * will follow if the capture is successful.
+ * + * @param child Child the user is attempting to capture + * @param pointerId ID of the pointer attempting the capture + * @return true if capture should be allowed, false otherwise + */ + public abstract boolean tryCaptureView(View child, int pointerId); + /** + * Restrict the motion of the dragged child view along the horizontal axis. + * The default implementation does not allow horizontal motion; the extending + * class must override this method and provide the desired clamping. + * + * + * @param child Child view being dragged + * @param left Attempted motion along the X axis + * @param dx Proposed change in position for left + * @return The new clamped position for left + */ + public int clampViewPositionHorizontal(View child, int left, int dx) { + return 0; + } + /** + * Restrict the motion of the dragged child view along the vertical axis. + * The default implementation does not allow vertical motion; the extending + * class must override this method and provide the desired clamping. + * + * + * @param child Child view being dragged + * @param top Attempted motion along the Y axis + * @param dy Proposed change in position for top + * @return The new clamped position for top + */ + public int clampViewPositionVertical(View child, int top, int dy) { + return 0; + } + } + /** + * Interpolator defining the animation curve for mScroller + */ + private static final Interpolator sInterpolator = new Interpolator() { + public float getInterpolation(float t) { + t -= 1.0f; + return t * t * t * t * t + 1.0f; + } + }; + private final Runnable mSetIdleRunnable = new Runnable() { + public void run() { + setDragState(STATE_IDLE); + } + }; + /** + * Factory method to create a new ViewDragHelper. + * + * @param forParent Parent view to monitor + * @param cb Callback to provide information and receive events + * @return a new ViewDragHelper instance + */ + public static ViewDragHelper create(ViewGroup forParent, Callback cb) { + return new ViewDragHelper(forParent.getContext(), forParent, cb); + } + /** + * Factory method to create a new ViewDragHelper. + * + * @param forParent Parent view to monitor + * @param sensitivity Multiplier for how sensitive the helper should be about detecting + * the start of a drag. Larger values are more sensitive. 1.0f is normal. + * @param cb Callback to provide information and receive events + * @return a new ViewDragHelper instance + */ + public static ViewDragHelper create(ViewGroup forParent, float sensitivity, Callback cb) { + final ViewDragHelper helper = create(forParent, cb); + helper.mTouchSlop = (int) (helper.mTouchSlop * (1 / sensitivity)); + return helper; + } + /** + * Apps should use ViewDragHelper.create() to get a new instance. + * This will allow VDH to use internal compatibility implementations for different + * platform versions. + * + * @param context Context to initialize config-dependent params from + * @param forParent Parent view to monitor + */ + private ViewDragHelper(Context context, ViewGroup forParent, Callback cb) { + if (forParent == null) { + throw new IllegalArgumentException("Parent view may not be null"); + } + if (cb == null) { + throw new IllegalArgumentException("Callback may not be null"); + } + mParentView = forParent; + mCallback = cb; + final ViewConfiguration vc = ViewConfiguration.get(context); + final float density = context.getResources().getDisplayMetrics().density; + mEdgeSize = (int) (EDGE_SIZE * density + 0.5f); + mTouchSlop = vc.getScaledTouchSlop(); + mMaxVelocity = vc.getScaledMaximumFlingVelocity(); + mMinVelocity = vc.getScaledMinimumFlingVelocity(); + mScroller = ScrollerCompat.create(context, sInterpolator); + } + /** + * Set the minimum velocity that will be detected as having a magnitude greater than zero + * in pixels per second. Callback methods accepting a velocity will be clamped appropriately. + * + * @param minVel Minimum velocity to detect + */ + public void setMinVelocity(float minVel) { + mMinVelocity = minVel; + } + /** + * Return the currently configured minimum velocity. Any flings with a magnitude less + * than this value in pixels per second. Callback methods accepting a velocity will receive + * zero as a velocity value if the real detected velocity was below this threshold. + * + * @return the minimum velocity that will be detected + */ + public float getMinVelocity() { + return mMinVelocity; + } + /** + * Retrieve the current drag state of this helper. This will return one of + * {@link #STATE_IDLE}, {@link #STATE_DRAGGING} or {@link #STATE_SETTLING}. + * @return The current drag state + */ + public int getViewDragState() { + return mDragState; + } + /** + * Enable edge tracking for the selected edges of the parent view. + * The callback's {@link Callback#onEdgeTouched(int, int)} and + * {@link Callback#onEdgeDragStarted(int, int)} methods will only be invoked + * for edges for which edge tracking has been enabled. + * + * @param edgeFlags Combination of edge flags describing the edges to watch + * @see #EDGE_LEFT + * @see #EDGE_TOP + * @see #EDGE_RIGHT + * @see #EDGE_BOTTOM + */ + public void setEdgeTrackingEnabled(int edgeFlags) { + mTrackingEdges = edgeFlags; + } + /** + * Return the size of an edge. This is the range in pixels along the edges of this view + * that will actively detect edge touches or drags if edge tracking is enabled. + * + * @return The size of an edge in pixels + * @see #setEdgeTrackingEnabled(int) + */ + public int getEdgeSize() { + return mEdgeSize; + } + /** + * Capture a specific child view for dragging within the parent. The callback will be notified + * but {@link Callback#tryCaptureView(android.view.View, int)} will not be asked permission to + * capture this view. + * + * @param childView Child view to capture + * @param activePointerId ID of the pointer that is dragging the captured child view + */ + public void captureChildView(View childView, int activePointerId) { + if (childView.getParent() != mParentView) { + throw new IllegalArgumentException("captureChildView: parameter must be a descendant " + + "of the ViewDragHelper's tracked parent view (" + mParentView + ")"); + } + mCapturedView = childView; + mActivePointerId = activePointerId; + mCallback.onViewCaptured(childView, activePointerId); + setDragState(STATE_DRAGGING); + } + /** + * @return The currently captured view, or null if no view has been captured. + */ + public View getCapturedView() { + return mCapturedView; + } + /** + * @return The ID of the pointer currently dragging the captured view, + * or {@link #INVALID_POINTER}. + */ + public int getActivePointerId() { + return mActivePointerId; + } + /** + * @return The minimum distance in pixels that the user must travel to initiate a drag + */ + public int getTouchSlop() { + return mTouchSlop; + } + /** + * The result of a call to this method is equivalent to + * {@link #processTouchEvent(android.view.MotionEvent)} receiving an ACTION_CANCEL event. + */ + public void cancel() { + mActivePointerId = INVALID_POINTER; + clearMotionHistory(); + if (mVelocityTracker != null) { + mVelocityTracker.recycle(); + mVelocityTracker = null; + } + } + /** + * {@link #cancel()}, but also abort all motion in progress and snap to the end of any + * animation. + */ + public void abort() { + cancel(); + if (mDragState == STATE_SETTLING) { + final int oldX = mScroller.getCurrX(); + final int oldY = mScroller.getCurrY(); + mScroller.abortAnimation(); + final int newX = mScroller.getCurrX(); + final int newY = mScroller.getCurrY(); + mCallback.onViewPositionChanged(mCapturedView, newX, newY, newX - oldX, newY - oldY); + } + setDragState(STATE_IDLE); + } + /** + * Animate the viewchild to the given (left, top) position.
+ * If this method returns true, the caller should invoke {@link #continueSettling(boolean)}
+ * on each subsequent frame to continue the motion until it returns false. If this method
+ * returns false there is no further work to do to complete the movement.
+ *
+ * This operation does not count as a capture event, though {@link #getCapturedView()} + * will still report the sliding view while the slide is in progress.
+ * + * @param child Child view to capture and animate + * @param finalLeft Final left position of child + * @param finalTop Final top position of child + * @return true if animation should continue through {@link #continueSettling(boolean)} calls + */ + public boolean smoothSlideViewTo(View child, int finalLeft, int finalTop) { + mCapturedView = child; + mActivePointerId = INVALID_POINTER; + boolean continueSliding = forceSettleCapturedViewAt(finalLeft, finalTop, 0, 0); + if (!continueSliding && mDragState == STATE_IDLE && mCapturedView != null) { + // If we're in an IDLE state to begin with and aren't moving anywhere, we + // end up having a non-null capturedView with an IDLE dragState + mCapturedView = null; + } + return continueSliding; + } + /** + * Settle the captured view at the given (left, top) position. + * The appropriate velocity from prior motion will be taken into account. + * If this method returns true, the caller should invoke {@link #continueSettling(boolean)} + * on each subsequent frame to continue the motion until it returns false. If this method + * returns false there is no further work to do to complete the movement. + * + * @param finalLeft Settled left edge position for the captured view + * @param finalTop Settled top edge position for the captured view + * @return true if animation should continue through {@link #continueSettling(boolean)} calls + */ + public boolean settleCapturedViewAt(int finalLeft, int finalTop) { + if (!mReleaseInProgress) { + throw new IllegalStateException("Cannot settleCapturedViewAt outside of a call to " + + "Callback#onViewReleased"); + } + return forceSettleCapturedViewAt(finalLeft, finalTop, + (int) VelocityTrackerCompat.getXVelocity(mVelocityTracker, mActivePointerId), + (int) VelocityTrackerCompat.getYVelocity(mVelocityTracker, mActivePointerId)); + } + /** + * Settle the captured view at the given (left, top) position. + * + * @param finalLeft Target left position for the captured view + * @param finalTop Target top position for the captured view + * @param xvel Horizontal velocity + * @param yvel Vertical velocity + * @return true if animation should continue through {@link #continueSettling(boolean)} calls + */ + private boolean forceSettleCapturedViewAt(int finalLeft, int finalTop, int xvel, int yvel) { + final int startLeft = mCapturedView.getLeft(); + final int startTop = mCapturedView.getTop(); + final int dx = finalLeft - startLeft; + final int dy = finalTop - startTop; + if (dx == 0 && dy == 0) { + // Nothing to do. Send callbacks, be done. + mScroller.abortAnimation(); + setDragState(STATE_IDLE); + return false; + } + final int duration = computeSettleDuration(mCapturedView, dx, dy, xvel, yvel); + mScroller.startScroll(startLeft, startTop, dx, dy, duration); + setDragState(STATE_SETTLING); + return true; + } + private int computeSettleDuration(View child, int dx, int dy, int xvel, int yvel) { + xvel = clampMag(xvel, (int) mMinVelocity, (int) mMaxVelocity); + yvel = clampMag(yvel, (int) mMinVelocity, (int) mMaxVelocity); + final int absDx = Math.abs(dx); + final int absDy = Math.abs(dy); + final int absXVel = Math.abs(xvel); + final int absYVel = Math.abs(yvel); + final int addedVel = absXVel + absYVel; + final int addedDistance = absDx + absDy; + final float xweight = xvel != 0 ? (float) absXVel / addedVel : + (float) absDx / addedDistance; + final float yweight = yvel != 0 ? (float) absYVel / addedVel : + (float) absDy / addedDistance; + int xduration = computeAxisDuration(dx, xvel, mCallback.getViewHorizontalDragRange(child)); + int yduration = computeAxisDuration(dy, yvel, mCallback.getViewVerticalDragRange(child)); + return (int) (xduration * xweight + yduration * yweight); + } + private int computeAxisDuration(int delta, int velocity, int motionRange) { + if (delta == 0) { + return 0; + } + final int width = mParentView.getWidth(); + final int halfWidth = width / 2; + final float distanceRatio = Math.min(1f, (float) Math.abs(delta) / width); + final float distance = halfWidth + halfWidth * + distanceInfluenceForSnapDuration(distanceRatio); + int duration; + velocity = Math.abs(velocity); + if (velocity > 0) { + duration = 4 * Math.round(1000 * Math.abs(distance / velocity)); + } else { + final float range = (float) Math.abs(delta) / motionRange; + duration = (int) ((range + 1) * BASE_SETTLE_DURATION); + } + return Math.min(duration, MAX_SETTLE_DURATION); + } + /** + * Clamp the magnitude of value for absMin and absMax. + * If the value is below the minimum, it will be clamped to zero. + * If the value is above the maximum, it will be clamped to the maximum. + * + * @param value Value to clamp + * @param absMin Absolute value of the minimum significant value to return + * @param absMax Absolute value of the maximum value to return + * @return The clamped value with the same sign asvalue
+ */
+ private int clampMag(int value, int absMin, int absMax) {
+ final int absValue = Math.abs(value);
+ if (absValue < absMin) return 0;
+ if (absValue > absMax) return value > 0 ? absMax : -absMax;
+ return value;
+ }
+ /**
+ * Clamp the magnitude of value for absMin and absMax.
+ * If the value is below the minimum, it will be clamped to zero.
+ * If the value is above the maximum, it will be clamped to the maximum.
+ *
+ * @param value Value to clamp
+ * @param absMin Absolute value of the minimum significant value to return
+ * @param absMax Absolute value of the maximum value to return
+ * @return The clamped value with the same sign as value
+ */
+ private float clampMag(float value, float absMin, float absMax) {
+ final float absValue = Math.abs(value);
+ if (absValue < absMin) return 0;
+ if (absValue > absMax) return value > 0 ? absMax : -absMax;
+ return value;
+ }
+ private float distanceInfluenceForSnapDuration(float f) {
+ f -= 0.5f; // center the values about 0.
+ f *= 0.3f * Math.PI / 2.0f;
+ return (float) Math.sin(f);
+ }
+ /**
+ * Settle the captured view based on standard free-moving fling behavior.
+ * The caller should invoke {@link #continueSettling(boolean)} on each subsequent frame
+ * to continue the motion until it returns false.
+ *
+ * @param minLeft Minimum X position for the view's left edge
+ * @param minTop Minimum Y position for the view's top edge
+ * @param maxLeft Maximum X position for the view's left edge
+ * @param maxTop Maximum Y position for the view's top edge
+ */
+ public void flingCapturedView(int minLeft, int minTop, int maxLeft, int maxTop) {
+ if (!mReleaseInProgress) {
+ throw new IllegalStateException("Cannot flingCapturedView outside of a call to " +
+ "Callback#onViewReleased");
+ }
+ mScroller.fling(mCapturedView.getLeft(), mCapturedView.getTop(),
+ (int) VelocityTrackerCompat.getXVelocity(mVelocityTracker, mActivePointerId),
+ (int) VelocityTrackerCompat.getYVelocity(mVelocityTracker, mActivePointerId),
+ minLeft, maxLeft, minTop, maxTop);
+ setDragState(STATE_SETTLING);
+ }
+ /**
+ * Move the captured settling view by the appropriate amount for the current time.
+ * If continueSettling returns true, the caller should call it again
+ * on the next frame to continue.
+ *
+ * @param deferCallbacks true if state callbacks should be deferred via posted message.
+ * Set this to true if you are calling this method from
+ * {@link android.view.View#computeScroll()} or similar methods
+ * invoked as part of layout or drawing.
+ * @return true if settle is still in progress
+ */
+ public boolean continueSettling(boolean deferCallbacks) {
+ if (mDragState == STATE_SETTLING) {
+ boolean keepGoing = mScroller.computeScrollOffset();
+ final int x = mScroller.getCurrX();
+ final int y = mScroller.getCurrY();
+ final int dx = x - mCapturedView.getLeft();
+ final int dy = y - mCapturedView.getTop();
+ if (dx != 0) {
+ ViewCompat.offsetLeftAndRight(mCapturedView, dx);
+ }
+ if (dy != 0) {
+ ViewCompat.offsetTopAndBottom(mCapturedView, dy);
+ }
+ if (dx != 0 || dy != 0) {
+ mCallback.onViewPositionChanged(mCapturedView, x, y, dx, dy);
+ }
+ if (keepGoing && x == mScroller.getFinalX() && y == mScroller.getFinalY()) {
+ // Close enough. The interpolator/scroller might think we're still moving
+ // but the user sure doesn't.
+ mScroller.abortAnimation();
+ keepGoing = false;
+ }
+ if (!keepGoing) {
+ if (deferCallbacks) {
+ mParentView.post(mSetIdleRunnable);
+ } else {
+ setDragState(STATE_IDLE);
+ }
+ }
+ }
+ return mDragState == STATE_SETTLING;
+ }
+ /**
+ * Like all callback events this must happen on the UI thread, but release
+ * involves some extra semantics. During a release (mReleaseInProgress)
+ * is the only time it is valid to call {@link #settleCapturedViewAt(int, int)}
+ * or {@link #flingCapturedView(int, int, int, int)}.
+ */
+ private void dispatchViewReleased(float xvel, float yvel) {
+ mReleaseInProgress = true;
+ mCallback.onViewReleased(mCapturedView, xvel, yvel);
+ mReleaseInProgress = false;
+ if (mDragState == STATE_DRAGGING) {
+ // onViewReleased didn't call a method that would have changed this. Go idle.
+ setDragState(STATE_IDLE);
+ }
+ }
+ private void clearMotionHistory() {
+ if (mInitialMotionX == null) {
+ return;
+ }
+ Arrays.fill(mInitialMotionX, 0);
+ Arrays.fill(mInitialMotionY, 0);
+ Arrays.fill(mLastMotionX, 0);
+ Arrays.fill(mLastMotionY, 0);
+ Arrays.fill(mInitialEdgesTouched, 0);
+ Arrays.fill(mEdgeDragsInProgress, 0);
+ Arrays.fill(mEdgeDragsLocked, 0);
+ mPointersDown = 0;
+ }
+ private void clearMotionHistory(int pointerId) {
+ if (mInitialMotionX == null || !isPointerDown(pointerId)) {
+ return;
+ }
+ mInitialMotionX[pointerId] = 0;
+ mInitialMotionY[pointerId] = 0;
+ mLastMotionX[pointerId] = 0;
+ mLastMotionY[pointerId] = 0;
+ mInitialEdgesTouched[pointerId] = 0;
+ mEdgeDragsInProgress[pointerId] = 0;
+ mEdgeDragsLocked[pointerId] = 0;
+ mPointersDown &= ~(1 << pointerId);
+ }
+ private void ensureMotionHistorySizeForId(int pointerId) {
+ if (mInitialMotionX == null || mInitialMotionX.length <= pointerId) {
+ float[] imx = new float[pointerId + 1];
+ float[] imy = new float[pointerId + 1];
+ float[] lmx = new float[pointerId + 1];
+ float[] lmy = new float[pointerId + 1];
+ int[] iit = new int[pointerId + 1];
+ int[] edip = new int[pointerId + 1];
+ int[] edl = new int[pointerId + 1];
+ if (mInitialMotionX != null) {
+ System.arraycopy(mInitialMotionX, 0, imx, 0, mInitialMotionX.length);
+ System.arraycopy(mInitialMotionY, 0, imy, 0, mInitialMotionY.length);
+ System.arraycopy(mLastMotionX, 0, lmx, 0, mLastMotionX.length);
+ System.arraycopy(mLastMotionY, 0, lmy, 0, mLastMotionY.length);
+ System.arraycopy(mInitialEdgesTouched, 0, iit, 0, mInitialEdgesTouched.length);
+ System.arraycopy(mEdgeDragsInProgress, 0, edip, 0, mEdgeDragsInProgress.length);
+ System.arraycopy(mEdgeDragsLocked, 0, edl, 0, mEdgeDragsLocked.length);
+ }
+ mInitialMotionX = imx;
+ mInitialMotionY = imy;
+ mLastMotionX = lmx;
+ mLastMotionY = lmy;
+ mInitialEdgesTouched = iit;
+ mEdgeDragsInProgress = edip;
+ mEdgeDragsLocked = edl;
+ }
+ }
+ private void saveInitialMotion(float x, float y, int pointerId) {
+ ensureMotionHistorySizeForId(pointerId);
+ mInitialMotionX[pointerId] = mLastMotionX[pointerId] = x;
+ mInitialMotionY[pointerId] = mLastMotionY[pointerId] = y;
+ mInitialEdgesTouched[pointerId] = getEdgesTouched((int) x, (int) y);
+ mPointersDown |= 1 << pointerId;
+ }
+ private void saveLastMotion(MotionEvent ev) {
+ final int pointerCount = MotionEventCompat.getPointerCount(ev);
+ for (int i = 0; i < pointerCount; i++) {
+ final int pointerId = MotionEventCompat.getPointerId(ev, i);
+ // If pointer is invalid then skip saving on ACTION_MOVE.
+ if (!isValidPointerForActionMove(pointerId)) {
+ continue;
+ }
+ final float x = MotionEventCompat.getX(ev, i);
+ final float y = MotionEventCompat.getY(ev, i);
+ mLastMotionX[pointerId] = x;
+ mLastMotionY[pointerId] = y;
+ }
+ }
+ /**
+ * Check if the given pointer ID represents a pointer that is currently down (to the best
+ * of the ViewDragHelper's knowledge).
+ *
+ * The state used to report this information is populated by the methods + * {@link #shouldInterceptTouchEvent(android.view.MotionEvent)} or + * {@link #processTouchEvent(android.view.MotionEvent)}. If one of these methods has not + * been called for all relevant MotionEvents to track, the information reported + * by this method may be stale or incorrect.
+ * + * @param pointerId pointer ID to check; corresponds to IDs provided by MotionEvent + * @return true if the pointer with the given ID is still down + */ + public boolean isPointerDown(int pointerId) { + return (mPointersDown & 1 << pointerId) != 0; + } + void setDragState(int state) { + mParentView.removeCallbacks(mSetIdleRunnable); + if (mDragState != state) { + mDragState = state; + mCallback.onViewDragStateChanged(state); + if (mDragState == STATE_IDLE) { + mCapturedView = null; + } + } + } + /** + * Attempt to capture the view with the given pointer ID. The callback will be involved. + * This will put us into the "dragging" state. If we've already captured this view with + * this pointer this method will immediately return true without consulting the callback. + * + * @param toCapture View to capture + * @param pointerId Pointer to capture with + * @return true if capture was successful + */ + boolean tryCaptureViewForDrag(View toCapture, int pointerId) { + if (toCapture == mCapturedView && mActivePointerId == pointerId) { + // Already done! + return true; + } + if (toCapture != null && mCallback.tryCaptureView(toCapture, pointerId)) { + mActivePointerId = pointerId; + captureChildView(toCapture, pointerId); + return true; + } + return false; + } + /** + * 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 along the X axis + * @param dy Delta scrolled in pixels along the Y axis + * @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 dy, 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, dy, x + scrollX - child.getLeft(), + y + scrollY - child.getTop())) { + return true; + } + } + } + return checkV && (ViewCompat.canScrollHorizontally(v, -dx) || + ViewCompat.canScrollVertically(v, -dy)); + } + /** + * Check if this event as provided to the parent view's onInterceptTouchEvent should + * cause the parent to intercept the touch event stream. + * + * @param ev MotionEvent provided to onInterceptTouchEvent + * @return true if the parent view should return true from onInterceptTouchEvent + */ + public boolean shouldInterceptTouchEvent(MotionEvent ev) { + final int action = MotionEventCompat.getActionMasked(ev); + final int actionIndex = MotionEventCompat.getActionIndex(ev); + if (action == MotionEvent.ACTION_DOWN) { + // Reset things for a new event stream, just in case we didn't get + // the whole previous stream. + cancel(); + } + if (mVelocityTracker == null) { + mVelocityTracker = VelocityTracker.obtain(); + } + mVelocityTracker.addMovement(ev); + switch (action) { + case MotionEvent.ACTION_DOWN: { + final float x = ev.getX(); + final float y = ev.getY(); + final int pointerId = MotionEventCompat.getPointerId(ev, 0); + saveInitialMotion(x, y, pointerId); + final View toCapture = findTopChildUnder((int) x, (int) y); + // Catch a settling view if possible. + if (toCapture == mCapturedView && mDragState == STATE_SETTLING) { + tryCaptureViewForDrag(toCapture, pointerId); + } + final int edgesTouched = mInitialEdgesTouched[pointerId]; + if ((edgesTouched & mTrackingEdges) != 0) { + mCallback.onEdgeTouched(edgesTouched & mTrackingEdges, pointerId); + } + break; + } + case MotionEventCompat.ACTION_POINTER_DOWN: { + final int pointerId = MotionEventCompat.getPointerId(ev, actionIndex); + final float x = MotionEventCompat.getX(ev, actionIndex); + final float y = MotionEventCompat.getY(ev, actionIndex); + saveInitialMotion(x, y, pointerId); + // A ViewDragHelper can only manipulate one view at a time. + if (mDragState == STATE_IDLE) { + final int edgesTouched = mInitialEdgesTouched[pointerId]; + if ((edgesTouched & mTrackingEdges) != 0) { + mCallback.onEdgeTouched(edgesTouched & mTrackingEdges, pointerId); + } + } else if (mDragState == STATE_SETTLING) { + // Catch a settling view if possible. + final View toCapture = findTopChildUnder((int) x, (int) y); + if (toCapture == mCapturedView) { + tryCaptureViewForDrag(toCapture, pointerId); + } + } + break; + } + case MotionEvent.ACTION_MOVE: { + if (mInitialMotionX == null || mInitialMotionY == null) break; + // First to cross a touch slop over a draggable view wins. Also report edge drags. + final int pointerCount = MotionEventCompat.getPointerCount(ev); + for (int i = 0; i < pointerCount; i++) { + final int pointerId = MotionEventCompat.getPointerId(ev, i); + // If pointer is invalid then skip the ACTION_MOVE. + if (!isValidPointerForActionMove(pointerId)) continue; + final float x = MotionEventCompat.getX(ev, i); + final float y = MotionEventCompat.getY(ev, i); + final float dx = x - mInitialMotionX[pointerId]; + final float dy = y - mInitialMotionY[pointerId]; + final View toCapture = findTopChildUnder((int) x, (int) y); + final boolean pastSlop = toCapture != null && checkTouchSlop(toCapture, dx, dy); + if (pastSlop) { + // check the callback's + // getView[Horizontal|Vertical]DragRange methods to know + // if you can move at all along an axis, then see if it + // would clamp to the same value. If you can't move at + // all in every dimension with a nonzero range, bail. + final int oldLeft = toCapture.getLeft(); + final int targetLeft = oldLeft + (int) dx; + final int newLeft = mCallback.clampViewPositionHorizontal(toCapture, + targetLeft, (int) dx); + final int oldTop = toCapture.getTop(); + final int targetTop = oldTop + (int) dy; + final int newTop = mCallback.clampViewPositionVertical(toCapture, targetTop, + (int) dy); + final int horizontalDragRange = mCallback.getViewHorizontalDragRange( + toCapture); + final int verticalDragRange = mCallback.getViewVerticalDragRange(toCapture); + if ((horizontalDragRange == 0 || horizontalDragRange > 0 + && newLeft == oldLeft) && (verticalDragRange == 0 + || verticalDragRange > 0 && newTop == oldTop)) { + break; + } + } + reportNewEdgeDrags(dx, dy, pointerId); + if (mDragState == STATE_DRAGGING) { + // Callback might have started an edge drag + break; + } + if (pastSlop && tryCaptureViewForDrag(toCapture, pointerId)) { + break; + } + } + saveLastMotion(ev); + break; + } + case MotionEventCompat.ACTION_POINTER_UP: { + final int pointerId = MotionEventCompat.getPointerId(ev, actionIndex); + clearMotionHistory(pointerId); + break; + } + case MotionEvent.ACTION_UP: + case MotionEvent.ACTION_CANCEL: { + cancel(); + break; + } + } + return mDragState == STATE_DRAGGING; + } + /** + * Process a touch event received by the parent view. This method will dispatch callback events + * as needed before returning. The parent view's onTouchEvent implementation should call this. + * + * @param ev The touch event received by the parent view + */ + public void processTouchEvent(MotionEvent ev) { + final int action = MotionEventCompat.getActionMasked(ev); + final int actionIndex = MotionEventCompat.getActionIndex(ev); + if (action == MotionEvent.ACTION_DOWN) { + // Reset things for a new event stream, just in case we didn't get + // the whole previous stream. + cancel(); + } + if (mVelocityTracker == null) { + mVelocityTracker = VelocityTracker.obtain(); + } + mVelocityTracker.addMovement(ev); + switch (action) { + case MotionEvent.ACTION_DOWN: { + final float x = ev.getX(); + final float y = ev.getY(); + final int pointerId = MotionEventCompat.getPointerId(ev, 0); + final View toCapture = findTopChildUnder((int) x, (int) y); + saveInitialMotion(x, y, pointerId); + // Since the parent is already directly processing this touch event, + // there is no reason to delay for a slop before dragging. + // Start immediately if possible. + tryCaptureViewForDrag(toCapture, pointerId); + final int edgesTouched = mInitialEdgesTouched[pointerId]; + if ((edgesTouched & mTrackingEdges) != 0) { + mCallback.onEdgeTouched(edgesTouched & mTrackingEdges, pointerId); + } + break; + } + case MotionEventCompat.ACTION_POINTER_DOWN: { + final int pointerId = MotionEventCompat.getPointerId(ev, actionIndex); + final float x = MotionEventCompat.getX(ev, actionIndex); + final float y = MotionEventCompat.getY(ev, actionIndex); + saveInitialMotion(x, y, pointerId); + // A ViewDragHelper can only manipulate one view at a time. + if (mDragState == STATE_IDLE) { + // If we're idle we can do anything! Treat it like a normal down event. + final View toCapture = findTopChildUnder((int) x, (int) y); + tryCaptureViewForDrag(toCapture, pointerId); + final int edgesTouched = mInitialEdgesTouched[pointerId]; + if ((edgesTouched & mTrackingEdges) != 0) { + mCallback.onEdgeTouched(edgesTouched & mTrackingEdges, pointerId); + } + } else if (isCapturedViewUnder((int) x, (int) y)) { + // We're still tracking a captured view. If the same view is under this + // point, we'll swap to controlling it with this pointer instead. + // (This will still work if we're "catching" a settling view.) + tryCaptureViewForDrag(mCapturedView, pointerId); + } + break; + } + case MotionEvent.ACTION_MOVE: { + if (mDragState == STATE_DRAGGING) { + // If pointer is invalid then skip the ACTION_MOVE. + if (!isValidPointerForActionMove(mActivePointerId)) break; + final int index = MotionEventCompat.findPointerIndex(ev, mActivePointerId); + final float x = MotionEventCompat.getX(ev, index); + final float y = MotionEventCompat.getY(ev, index); + final int idx = (int) (x - mLastMotionX[mActivePointerId]); + final int idy = (int) (y - mLastMotionY[mActivePointerId]); + dragTo(mCapturedView.getLeft() + idx, mCapturedView.getTop() + idy, idx, idy); + saveLastMotion(ev); + } else { + // Check to see if any pointer is now over a draggable view. + final int pointerCount = MotionEventCompat.getPointerCount(ev); + for (int i = 0; i < pointerCount; i++) { + final int pointerId = MotionEventCompat.getPointerId(ev, i); + // If pointer is invalid then skip the ACTION_MOVE. + if (!isValidPointerForActionMove(pointerId)) continue; + final float x = MotionEventCompat.getX(ev, i); + final float y = MotionEventCompat.getY(ev, i); + final float dx = x - mInitialMotionX[pointerId]; + final float dy = y - mInitialMotionY[pointerId]; + reportNewEdgeDrags(dx, dy, pointerId); + if (mDragState == STATE_DRAGGING) { + // Callback might have started an edge drag. + break; + } + final View toCapture = findTopChildUnder((int) x, (int) y); + if (checkTouchSlop(toCapture, dx, dy) && + tryCaptureViewForDrag(toCapture, pointerId)) { + break; + } + } + saveLastMotion(ev); + } + break; + } + case MotionEventCompat.ACTION_POINTER_UP: { + final int pointerId = MotionEventCompat.getPointerId(ev, actionIndex); + if (mDragState == STATE_DRAGGING && pointerId == mActivePointerId) { + // Try to find another pointer that's still holding on to the captured view. + int newActivePointer = INVALID_POINTER; + final int pointerCount = MotionEventCompat.getPointerCount(ev); + for (int i = 0; i < pointerCount; i++) { + final int id = MotionEventCompat.getPointerId(ev, i); + if (id == mActivePointerId) { + // This one's going away, skip. + continue; + } + final float x = MotionEventCompat.getX(ev, i); + final float y = MotionEventCompat.getY(ev, i); + if (findTopChildUnder((int) x, (int) y) == mCapturedView && + tryCaptureViewForDrag(mCapturedView, id)) { + newActivePointer = mActivePointerId; + break; + } + } + if (newActivePointer == INVALID_POINTER) { + // We didn't find another pointer still touching the view, release it. + releaseViewForPointerUp(); + } + } + clearMotionHistory(pointerId); + break; + } + case MotionEvent.ACTION_UP: { + if (mDragState == STATE_DRAGGING) { + releaseViewForPointerUp(); + } + cancel(); + break; + } + case MotionEvent.ACTION_CANCEL: { + if (mDragState == STATE_DRAGGING) { + dispatchViewReleased(0, 0); + } + cancel(); + break; + } + } + } + private void reportNewEdgeDrags(float dx, float dy, int pointerId) { + int dragsStarted = 0; + if (checkNewEdgeDrag(dx, dy, pointerId, EDGE_LEFT)) { + dragsStarted |= EDGE_LEFT; + } + if (checkNewEdgeDrag(dy, dx, pointerId, EDGE_TOP)) { + dragsStarted |= EDGE_TOP; + } + if (checkNewEdgeDrag(dx, dy, pointerId, EDGE_RIGHT)) { + dragsStarted |= EDGE_RIGHT; + } + if (checkNewEdgeDrag(dy, dx, pointerId, EDGE_BOTTOM)) { + dragsStarted |= EDGE_BOTTOM; + } + if (dragsStarted != 0) { + mEdgeDragsInProgress[pointerId] |= dragsStarted; + mCallback.onEdgeDragStarted(dragsStarted, pointerId); + } + } + private boolean checkNewEdgeDrag(float delta, float odelta, int pointerId, int edge) { + final float absDelta = Math.abs(delta); + final float absODelta = Math.abs(odelta); + if ((mInitialEdgesTouched[pointerId] & edge) != edge || (mTrackingEdges & edge) == 0 || + (mEdgeDragsLocked[pointerId] & edge) == edge || + (mEdgeDragsInProgress[pointerId] & edge) == edge || + (absDelta <= mTouchSlop && absODelta <= mTouchSlop)) { + return false; + } + if (absDelta < absODelta * 0.5f && mCallback.onEdgeLock(edge)) { + mEdgeDragsLocked[pointerId] |= edge; + return false; + } + return (mEdgeDragsInProgress[pointerId] & edge) == 0 && absDelta > mTouchSlop; + } + /** + * Check if we've crossed a reasonable touch slop for the given child view. + * If the child cannot be dragged along the horizontal or vertical axis, motion + * along that axis will not count toward the slop check. + * + * @param child Child to check + * @param dx Motion since initial position along X axis + * @param dy Motion since initial position along Y axis + * @return true if the touch slop has been crossed + */ + + private boolean checkTouchSlop(View child, float dx, float dy) { + if (child == null) { + return false; + } + final boolean checkHorizontal = mCallback.getViewHorizontalDragRange(child) > 0; + final boolean checkVertical = mCallback.getViewVerticalDragRange(child) > 0; + + float temp_dy = dy; + if(temp_dy<0) + temp_dy = -temp_dy; + + if (checkHorizontal && checkVertical) { + return dx * dx + dy * dy > mTouchSlop * mTouchSlop; + } else if (checkVertical) { + return Math.abs(dy) > mTouchSlop; + } else if (checkHorizontal && 3*temp_dy < dx) { + return Math.abs(dx) > mTouchSlop; + } + + return false; + } + /** + * Check if any pointer tracked in the current gesture has crossed + * the required slop threshold. + * + *This depends on internal state populated by + * {@link #shouldInterceptTouchEvent(android.view.MotionEvent)} or + * {@link #processTouchEvent(android.view.MotionEvent)}. You should only rely on + * the results of this method after all currently available touch data + * has been provided to one of these two methods.
+ * + * @param directions Combination of direction flags, see {@link #DIRECTION_HORIZONTAL}, + * {@link #DIRECTION_VERTICAL}, {@link #DIRECTION_ALL} + * @return true if the slop threshold has been crossed, false otherwise + */ + public boolean checkTouchSlop(int directions) { + final int count = mInitialMotionX.length; + for (int i = 0; i < count; i++) { + if (checkTouchSlop(directions, i)) { + return true; + } + } + return false; + } + /** + * Check if the specified pointer tracked in the current gesture has crossed + * the required slop threshold. + * + *This depends on internal state populated by + * {@link #shouldInterceptTouchEvent(android.view.MotionEvent)} or + * {@link #processTouchEvent(android.view.MotionEvent)}. You should only rely on + * the results of this method after all currently available touch data + * has been provided to one of these two methods.
+ * + * @param directions Combination of direction flags, see {@link #DIRECTION_HORIZONTAL}, + * {@link #DIRECTION_VERTICAL}, {@link #DIRECTION_ALL} + * @param pointerId ID of the pointer to slop check as specified by MotionEvent + * @return true if the slop threshold has been crossed, false otherwise + */ + public boolean checkTouchSlop(int directions, int pointerId) { + if (!isPointerDown(pointerId)) { + return false; + } + final boolean checkHorizontal = (directions & DIRECTION_HORIZONTAL) == DIRECTION_HORIZONTAL; + final boolean checkVertical = (directions & DIRECTION_VERTICAL) == DIRECTION_VERTICAL; + final float dx = mLastMotionX[pointerId] - mInitialMotionX[pointerId]; + final float dy = mLastMotionY[pointerId] - mInitialMotionY[pointerId]; + if (checkHorizontal && checkVertical) { + return dx * dx + dy * dy > mTouchSlop * mTouchSlop; + } else if (checkHorizontal) { + return Math.abs(dx) > mTouchSlop; + } else if (checkVertical) { + return Math.abs(dy) > mTouchSlop; + } + return false; + } + /** + * Check if any of the edges specified were initially touched in the currently active gesture. + * If there is no currently active gesture this method will return false. + * + * @param edges Edges to check for an initial edge touch. See {@link #EDGE_LEFT}, + * {@link #EDGE_TOP}, {@link #EDGE_RIGHT}, {@link #EDGE_BOTTOM} and + * {@link #EDGE_ALL} + * @return true if any of the edges specified were initially touched in the current gesture + */ + public boolean isEdgeTouched(int edges) { + final int count = mInitialEdgesTouched.length; + for (int i = 0; i < count; i++) { + if (isEdgeTouched(edges, i)) { + return true; + } + } + return false; + } + /** + * Check if any of the edges specified were initially touched by the pointer with + * the specified ID. If there is no currently active gesture or if there is no pointer with + * the given ID currently down this method will return false. + * + * @param edges Edges to check for an initial edge touch. See {@link #EDGE_LEFT}, + * {@link #EDGE_TOP}, {@link #EDGE_RIGHT}, {@link #EDGE_BOTTOM} and + * {@link #EDGE_ALL} + * @return true if any of the edges specified were initially touched in the current gesture + */ + public boolean isEdgeTouched(int edges, int pointerId) { + return isPointerDown(pointerId) && (mInitialEdgesTouched[pointerId] & edges) != 0; + } + private void releaseViewForPointerUp() { + mVelocityTracker.computeCurrentVelocity(1000, mMaxVelocity); + final float xvel = clampMag( + VelocityTrackerCompat.getXVelocity(mVelocityTracker, mActivePointerId), + mMinVelocity, mMaxVelocity); + final float yvel = clampMag( + VelocityTrackerCompat.getYVelocity(mVelocityTracker, mActivePointerId), + mMinVelocity, mMaxVelocity); + dispatchViewReleased(xvel, yvel); + } + private void dragTo(int left, int top, int dx, int dy) { + int clampedX = left; + int clampedY = top; + final int oldLeft = mCapturedView.getLeft(); + final int oldTop = mCapturedView.getTop(); + if (dx != 0) { + clampedX = mCallback.clampViewPositionHorizontal(mCapturedView, left, dx); + ViewCompat.offsetLeftAndRight(mCapturedView, clampedX - oldLeft); + } + if (dy != 0) { + clampedY = mCallback.clampViewPositionVertical(mCapturedView, top, dy); + ViewCompat.offsetTopAndBottom(mCapturedView, clampedY - oldTop); + } + if (dx != 0 || dy != 0) { + final int clampedDx = clampedX - oldLeft; + final int clampedDy = clampedY - oldTop; + mCallback.onViewPositionChanged(mCapturedView, clampedX, clampedY, + clampedDx, clampedDy); + } + } + /** + * Determine if the currently captured view is under the given point in the + * parent view's coordinate system. If there is no captured view this method + * will return false. + * + * @param x X position to test in the parent's coordinate system + * @param y Y position to test in the parent's coordinate system + * @return true if the captured view is under the given point, false otherwise + */ + public boolean isCapturedViewUnder(int x, int y) { + return isViewUnder(mCapturedView, x, y); + } + /** + * Determine if the supplied view is under the given point in the + * parent view's coordinate system. + * + * @param view Child view of the parent to hit test + * @param x X position to test in the parent's coordinate system + * @param y Y position to test in the parent's coordinate system + * @return true if the supplied view is under the given point, false otherwise + */ + public boolean isViewUnder(View view, int x, int y) { + if (view == null) { + return false; + } + return x >= view.getLeft() && + x < view.getRight() && + y >= view.getTop() && + y < view.getBottom(); + } + /** + * Find the topmost child under the given point within the parent view's coordinate system. + * The child order is determined using {@link Callback#getOrderedChildIndex(int)}. + * + * @param x X position to test in the parent's coordinate system + * @param y Y position to test in the parent's coordinate system + * @return The topmost child view under (x, y) or null if none found. + */ + public View findTopChildUnder(int x, int y) { + final int childCount = mParentView.getChildCount(); + for (int i = childCount - 1; i >= 0; i--) { + final View child = mParentView.getChildAt(mCallback.getOrderedChildIndex(i)); + if (x >= child.getLeft() && x < child.getRight() && + y >= child.getTop() && y < child.getBottom()) { + return child; + } + } + return null; + } + private int getEdgesTouched(int x, int y) { + int result = 0; + if (x < mParentView.getLeft() + mEdgeSize) result |= EDGE_LEFT; + if (y < mParentView.getTop() + mEdgeSize) result |= EDGE_TOP; + if (x > mParentView.getRight() - mEdgeSize) result |= EDGE_RIGHT; + if (y > mParentView.getBottom() - mEdgeSize) result |= EDGE_BOTTOM; + return result; + } + private boolean isValidPointerForActionMove(int pointerId) { + if (!isPointerDown(pointerId)) { + Log.e(TAG, "Ignoring pointerId=" + pointerId + " because ACTION_DOWN was not received " + + "for this pointer before ACTION_MOVE. It likely happened because " + + " ViewDragHelper did not receive all the events in the event stream."); + return false; + } + return true; + } +} diff --git a/library/src/main/java/com/r0adkll/slidr/widget/SliderPanel.java b/library/src/main/java/com/r0adkll/slidr/widget/SliderPanel.java index 7006c44..267f545 100644 --- a/library/src/main/java/com/r0adkll/slidr/widget/SliderPanel.java +++ b/library/src/main/java/com/r0adkll/slidr/widget/SliderPanel.java @@ -8,12 +8,13 @@ import android.content.Context; import android.support.v4.view.ViewCompat; import android.support.v4.view.ViewGroupCompat; -import android.support.v4.widget.ViewDragHelper; + import android.view.MotionEvent; import android.view.View; import android.widget.FrameLayout; import com.r0adkll.slidr.model.SlidrConfig; +import com.r0adkll.slidr.model.ViewDragHelper; /** * Project: PilotPass