Java tutorial
/* * Copyright (C) 2013 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.hynet.mergepay.components.widget.panellayout; import android.content.Context; import android.support.v4.view.MotionEventCompat; import android.support.v4.view.VelocityTrackerCompat; import android.support.v4.view.ViewCompat; import android.support.v4.widget.ScrollerCompat; import android.view.MotionEvent; import android.view.VelocityTracker; import android.view.View; import android.view.ViewConfiguration; import android.view.ViewGroup; import android.view.animation.Interpolator; import java.util.Arrays; public class ViewDragHelper { private static final int INVALID_POINTER = -1; public static final int STATE_IDLE = 0; private static final int STATE_DRAGGING = 1; private static final int STATE_SETTLING = 2; private static final int EDGE_LEFT = 1 << 0; private static final int EDGE_RIGHT = 1 << 1; private static final int EDGE_TOP = 1 << 2; private static final int EDGE_BOTTOM = 1 << 3; private static final int EDGE_ALL = EDGE_LEFT | EDGE_TOP | EDGE_RIGHT | EDGE_BOTTOM; private static final int DIRECTION_HORIZONTAL = 1 << 0; private static final int DIRECTION_VERTICAL = 1 << 1; private static final int DIRECTION_ALL = DIRECTION_HORIZONTAL | DIRECTION_VERTICAL; private static final int EDGE_SIZE = 20; // dp private static final int BASE_SETTLE_DURATION = 256; // ms private static final int MAX_SETTLE_DURATION = 600; // ms // Current drag state; idle, dragging or settling private int mDragState; // Distance to travel before a drag may begin private int mTouchSlop; // Last known position/pointer tracking private int mActivePointerId = INVALID_POINTER; private float[] mInitialMotionX; private float[] mInitialMotionY; private float[] mLastMotionX; private float[] mLastMotionY; private int[] mInitialEdgesTouched; private int[] mEdgeDragsInProgress; private int[] mEdgeDragsLocked; private int mPointersDown; private VelocityTracker mVelocityTracker; private float mMaxVelocity; private float mMinVelocity; private int mEdgeSize; private int mTrackingEdges; private ScrollerCompat mScroller; private final Callback mCallback; private View mCapturedView; private boolean mReleaseInProgress; private final ViewGroup mParentView; public static abstract class Callback { public void onViewDragStateChanged(int state) { } public void onViewPositionChanged(View changedView, int left, int top, int dx, int dy) { } public void onViewCaptured(View capturedChild, int activePointerId) { } public void onViewReleased(View releasedChild, float xvel, float yvel) { } public void onEdgeTouched(int edgeFlags, int pointerId) { } public boolean onEdgeLock(int edgeFlags) { return false; } public void onEdgeDragStarted(int edgeFlags, int pointerId) { } public int getOrderedChildIndex(int index) { return index; } public int getViewHorizontalDragRange(View child) { return 0; } public int getViewVerticalDragRange(View child) { return 0; } public abstract boolean tryCaptureView(View child, int pointerId); public int clampViewPositionHorizontal(View child, int left, int dx) { return 0; } public int clampViewPositionVertical(View child, int top, int dy) { return 0; } } 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); } }; public static ViewDragHelper create(ViewGroup forParent, Callback cb) { return new ViewDragHelper(forParent.getContext(), forParent, null, cb); } public static ViewDragHelper create(ViewGroup forParent, Interpolator interpolator, Callback cb) { return new ViewDragHelper(forParent.getContext(), forParent, interpolator, cb); } 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; } public static ViewDragHelper create(ViewGroup forParent, float sensitivity, Interpolator interpolator, Callback cb) { final ViewDragHelper helper = create(forParent, interpolator, cb); helper.mTouchSlop = (int) (helper.mTouchSlop * (1 / sensitivity)); return helper; } private ViewDragHelper(Context context, ViewGroup forParent, Interpolator interpolator, 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, interpolator != null ? interpolator : sInterpolator); } public void setMinVelocity(float minVel) { mMinVelocity = minVel; } public float getMinVelocity() { return mMinVelocity; } public int getViewDragState() { return mDragState; } public void setEdgeTrackingEnabled(int edgeFlags) { mTrackingEdges = edgeFlags; } public int getEdgeSize() { return mEdgeSize; } 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); } public View getCapturedView() { return mCapturedView; } public int getActivePointerId() { return mActivePointerId; } public int getTouchSlop() { return mTouchSlop; } public void cancel() { mActivePointerId = INVALID_POINTER; clearMotionHistory(); if (mVelocityTracker != null) { mVelocityTracker.recycle(); mVelocityTracker = null; } } 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); } public boolean smoothSlideViewTo(View child, int finalLeft, int finalTop) { mCapturedView = child; mActivePointerId = INVALID_POINTER; return forceSettleCapturedViewAt(finalLeft, finalTop, 0, 0); } 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)); } 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); } 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; } 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); } 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); } public boolean continueSettling(boolean deferCallbacks) { // Make sure, there is a captured view if (mCapturedView == null) { return false; } 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 (!keepGoing && dy != 0) { //fix #525 //Invalid drag state mCapturedView.setTop(0); return true; } if (dx != 0) { mCapturedView.offsetLeftAndRight(dx); } if (dy != 0) { mCapturedView.offsetTopAndBottom(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 = mScroller.isFinished(); } if (!keepGoing) { if (deferCallbacks) { mParentView.post(mSetIdleRunnable); } else { setDragState(STATE_IDLE); } } } return mDragState == STATE_SETTLING; } 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 || mInitialMotionX.length <= 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); final float x = MotionEventCompat.getX(ev, i); final float y = MotionEventCompat.getY(ev, i); // Sometimes we can try and save last motion for a pointer never recorded in initial motion. In this case we just discard it. if (mLastMotionX != null && mLastMotionY != null && mLastMotionX.length > pointerId && mLastMotionY.length > pointerId) { mLastMotionX[pointerId] = x; mLastMotionY[pointerId] = y; } } } public boolean isPointerDown(int pointerId) { return (mPointersDown & 1 << pointerId) != 0; } void setDragState(int state) { if (mDragState != state) { mDragState = state; mCallback.onViewDragStateChanged(state); if (mDragState == STATE_IDLE) { mCapturedView = null; } } } 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; } 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)); } 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: { // 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 && mInitialMotionX != null && mInitialMotionY != null; i++) { final int pointerId = MotionEventCompat.getPointerId(ev, i); if (pointerId >= mInitialMotionX.length || pointerId >= mInitialMotionY.length) { 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) mInitialMotionX[pointerId], (int) mInitialMotionY[pointerId]); if (toCapture != null && checkTouchSlop(toCapture, dx, dy) && 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; } 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) { 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); 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) mInitialMotionX[pointerId], (int) mInitialMotionY[pointerId]); 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; } 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; 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; } 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; } 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; } 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; } public boolean isEdgeTouched(int edges, int pointerId) { return isPointerDown(pointerId) && (mInitialEdgesTouched[pointerId] & edges) != 0; } public boolean isDragging() { return mDragState == STATE_DRAGGING; } 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); mCapturedView.offsetLeftAndRight(clampedX - oldLeft); } if (dy != 0) { clampedY = mCallback.clampViewPositionVertical(mCapturedView, top, dy); mCapturedView.offsetTopAndBottom(clampedY - oldTop); } if (dx != 0 || dy != 0) { final int clampedDx = clampedX - oldLeft; final int clampedDy = clampedY - oldTop; mCallback.onViewPositionChanged(mCapturedView, clampedX, clampedY, clampedDx, clampedDy); } } public boolean isCapturedViewUnder(int x, int y) { return isViewUnder(mCapturedView, x, y); } 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(); } 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; } }