Android侧滑效果简单实现代码

public class ViewDragHelper { private static final String TAG = "ViewDragHelper"; public static final int INVALID_POINTER = -1 public static final int STATE_IDLE = 0; public static final int STATE_DRAGGING = 1; public static final int STATE_SETTLING = 2; public static final int EDGE_LEFT = 1 << 0; public static final int EDGE_RIGHT = 1 << 1 public static final int EDGE_TOP = 1 << 2; public static final int EDGE_BOTTOM = 1 << 3 public static final int EDGE_ALL = EDGE_LEFT | EDGE_TOP | EDGE_RIGHT | EDGE_BOTTOM; public static final int DIRECTION_HORIZONTAL = 1 << 0; public static final int DIRECTION_VERTICAL = 1 << 1; public 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 final float mMaxVelocity; private float mMinVelocity; private final int mEdgeSize; private int mTrackingEdges; private final ScrollerCompat mScroller; private final Callback mCallback; private View mCapturedView; private boolean mReleaseInProgress; private final ViewGroup mParentView; 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);  } }; 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); } 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;  } } public static ViewDragHelper create(ViewGroup forParent, Callback cb) {  return new ViewDragHelper(forParent.getContext(), forParent, 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 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;  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; } 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 static 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 static 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 static 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) {  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) {    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 = false;   }   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) {   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);   mLastMotionX[pointerId] = x;   mLastMotionY[pointerId] = y;  } } 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;   }  } } 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: {    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);     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;   }   default:    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) 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;   }   default:    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; } 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; }}

public class DragLayout extends FrameLayout { private static final boolean IS_SHOW_SHADOW = true; //手势处理类 private GestureDetectorCompat gestureDetector; //视图拖拽移动帮助类 private ViewDragHelper dragHelper; //滑动监听器 private DragListener dragListener; //水平拖拽的距离 private int range; //宽度 private int width; //高度 private int height; //main视图距离在ViewGroup距离左边的距离 private int mainLeft; private Context context; private ImageView ivShadow; //左侧布局 private RelativeLayout vgLeft; //右侧(主界面布局) private CustomRelativeLayout vgMain; //页面状态 默认为关闭 private Status status = Status.CLOSE; private final ViewDragHelper.Callback dragHelperCallback = new ViewDragHelper.Callback() {  @Override  public int clampViewPositionHorizontal(View child, int left, int dx) {   if (mainLeft + dx < 0) {    return 0;   } else if (mainLeft + dx > range) {    return range;   } else {    return left;   }  }  @Override  public boolean tryCaptureView(View child, int pointerId) {   return true;  }  @Override  public int getViewHorizontalDragRange(View child) {   return width;  }  @Override  public void onViewReleased(View releasedChild, float xvel, float yvel) {   super.onViewReleased(releasedChild, xvel, yvel);   if (xvel > 0) {    open();   } else if (xvel < 0) {    close();   } else if (releasedChild == vgMain && mainLeft > range * 0.3) {    open();   } else if (releasedChild == vgLeft && mainLeft > range * 0.7) {    open();   } else {    close();   }  }  @Override  public void onViewPositionChanged(View changedView, int left, int top,           int dx, int dy) {   if (changedView == vgMain) {    mainLeft = left;   } else {    mainLeft = mainLeft + left;   }   if (mainLeft < 0) {    mainLeft = 0;   } else if (mainLeft > range) {    mainLeft = range;   }   if (IS_SHOW_SHADOW) {    ivShadow.layout(mainLeft, 0, mainLeft + width, height);   }   if (changedView == vgLeft) {    vgLeft.layout(0, 0, width, height);    vgMain.layout(mainLeft, 0, mainLeft + width, height);   }   dispatchDragEvent(mainLeft);  } }; public DragLayout(Context context) {  this(context, null); } public DragLayout(Context context, AttributeSet attrs) {  this(context, attrs, 0);  this.context = context; } public DragLayout(Context context, AttributeSet attrs, int defStyle) {  super(context, attrs, defStyle);  gestureDetector = new GestureDetectorCompat(context, new YScrollDetector());  dragHelper = ViewDragHelper.create(this, dragHelperCallback); } class YScrollDetector extends GestureDetector.SimpleOnGestureListener {  @Override  public boolean onScroll(MotionEvent e1, MotionEvent e2, float dx, float dy) {   return Math.abs(dy) <= Math.abs(dx);  } } /**  * 滑动相关回调接口  */ public interface DragListener {  //界面打开  public void onOpen();  //界面关闭  public void onClose();  //界面滑动过程中  public void onDrag(float percent); } public void setDragListener(DragListener dragListener) {  this.dragListener = dragListener; } /**  * 布局加载完成回调  * 做一些初始化的操作  */ @Override protected void onFinishInflate() {  super.onFinishInflate();  if (IS_SHOW_SHADOW) {   ivShadow = new ImageView(context);   ivShadow.setImageResource(R.mipmap.shadow);   LayoutParams lp = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);   addView(ivShadow, 1, lp);  }  //左侧界面  vgLeft = (RelativeLayout) getChildAt(0);  //右侧(主)界面  vgMain = (CustomRelativeLayout) getChildAt(IS_SHOW_SHADOW ? 2 : 1);  vgMain.setDragLayout(this);  vgLeft.setClickable(true);  vgMain.setClickable(true); } public ViewGroup getVgMain() {  return vgMain; } public ViewGroup getVgLeft() {  return vgLeft; } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) {  super.onSizeChanged(w, h, oldw, oldh);  width = vgLeft.getMeasuredWidth();  height = vgLeft.getMeasuredHeight();  //可以水平拖拽滑动的距离 一共为屏幕宽度的80%  range = (int) (width * 0.8f); } @Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) {  vgLeft.layout(0, 0, width, height);  vgMain.layout(mainLeft, 0, mainLeft + width, height); } /**  * 拦截触摸事件  * @param ev  * @return  */ @Override public boolean onInterceptTouchEvent(MotionEvent ev) {  return dragHelper.shouldInterceptTouchEvent(ev) && gestureDetector.onTouchEvent(ev); } /**  * 将拦截的到事件给ViewDragHelper进行处理  * @param e  * @return  */ @Override public boolean onTouchEvent(MotionEvent e) {  try {   dragHelper.processTouchEvent(e);  } catch (Exception ex) {   ex.printStackTrace();  }  return false; } /**  * 进行处理拖拽事件  * @param mainLeft  */ private void dispatchDragEvent(int mainLeft) {  if (dragListener == null) {   return;  }  float percent = mainLeft / (float) range;  //滑动动画效果  animateView(percent);  //进行回调滑动的百分比  dragListener.onDrag(percent);  Status lastStatus = status;  if (lastStatus != getStatus() && status == Status.CLOSE) {   dragListener.onClose();  } else if (lastStatus != getStatus() && status == Status.OPEN) {   dragListener.onOpen();  } } /**  * 根据滑动的距离的比例,进行平移动画  * @param percent  */ private void animateView(float percent) {  float f1 = 1 - percent * 0.5f;  ViewHelper.setTranslationX(vgLeft, -vgLeft.getWidth() / 2.5f + vgLeft.getWidth() / 2.5f * percent);  if (IS_SHOW_SHADOW) {   //阴影效果视图大小进行缩放   ViewHelper.setScaleX(ivShadow, f1 * 1.2f * (1 - percent * 0.10f));   ViewHelper.setScaleY(ivShadow, f1 * 1.85f * (1 - percent * 0.10f));  } } /**  * 有加速度,当我们停止滑动的时候，该不会立即停止动画效果  */ @Override public void computeScroll() {  if (dragHelper.continueSettling(true)) {   ViewCompat.postInvalidateOnAnimation(this);  } } /**  * 页面状态(滑动,打开,关闭)  */ public enum Status {  DRAG, OPEN, CLOSE } /**  * 页面状态设置  * @return  */ public Status getStatus() {  if (mainLeft == 0) {   status = Status.CLOSE;  } else if (mainLeft == range) {   status = Status.OPEN;  } else {   status = Status.DRAG;  }  return status; } public void open() {  open(true); } public void open(boolean animate) {  if (animate) {   //继续滑动   if (dragHelper.smoothSlideViewTo(vgMain, range, 0)) {    ViewCompat.postInvalidateOnAnimation(this);   }  } else {   vgMain.layout(range, 0, range * 2, height);   dispatchDragEvent(range);  } } public void close() {  close(true); } public void close(boolean animate) {  if (animate) {   //继续滑动   if (dragHelper.smoothSlideViewTo(vgMain, 0, 0)) {    ViewCompat.postInvalidateOnAnimation(this);   }  } else {   vgMain.layout(0, 0, width, height);   dispatchDragEvent(0);  } }}

public class CustomRelativeLayout extends RelativeLayout { private DragLayout dl; public CustomRelativeLayout(Context context) {  super(context); } public CustomRelativeLayout(Context context, AttributeSet attrs) {  super(context, attrs); } public CustomRelativeLayout(Context context, AttributeSet attrs, int defStyleAttr) {  super(context, attrs, defStyleAttr); } public void setDragLayout(DragLayout dl) {  this.dl = dl; } @Override public boolean onInterceptTouchEvent(MotionEvent event) {  if (dl.getStatus() != DragLayout.Status.CLOSE) {   return true;  }  return super.onInterceptTouchEvent(event); } @Override public boolean onTouchEvent(MotionEvent event) {  if (dl.getStatus() != DragLayout.Status.CLOSE) {   if (event.getAction() == MotionEvent.ACTION_UP) {    dl.close();   }   return true;  }  return super.onTouchEvent(event); }}

public class BaseActivity extends FragmentActivity { @Override protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  this.requestWindowFeature(Window.FEATURE_NO_TITLE);  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {   //透明状态栏   getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);   //透明导航栏   getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);  } } /**  * 设置沉浸式状态栏  */ protected void setStatusBar() {  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {   final ViewGroup linear_bar = (ViewGroup) findViewById(R.id.rl_title);   final int statusHeight = getStatusBarHeight();   linear_bar.post(new Runnable() {    @Override    public void run() {     int titleHeight = linear_bar.getHeight();     android.widget.LinearLayout.LayoutParams params = (android.widget.LinearLayout.LayoutParams) linear_bar.getLayoutParams();     params.height = statusHeight + titleHeight;     linear_bar.setLayoutParams(params);    }   });  } } /**  * 获取状态栏的高度  * @return  */ protected int getStatusBarHeight(){  try  {   Class<?> c=Class.forName("com.android.internal.R$dimen");   Object obj=c.newInstance();   Field field=c.getField("status_bar_height");   int x=Integer.parseInt(field.get(obj).toString());   return getResources().getDimensionPixelSize(x);  }catch(Exception e){   e.printStackTrace();  }  return 0; }}

public class MainActivity extends BaseActivity { private DragLayout dl; private LinearLayout linearLayout; @Override protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_main);  initDragLayout(); } private void initDragLayout() {  dl = (DragLayout) findViewById(R.id.dl);  linearLayout =(LinearLayout) findViewById(R.id.aaa);  dl.setDragListener(new DragLayout.DragListener() {   //界面打开的时候   @Override   public void onOpen() {   }   //界面关闭的时候   @Override   public void onClose() {   }   //界面滑动的时候   @Override   public void onDrag(float percent) {   }  }); }}

public class OneFragment extends Fragment { private View mView; @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {  if(mView==null){   mView=inflater.inflate(R.layout.one_frag_layout,container,false);  }  return mView; }}

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="center" android:id="@+id/aaa" > <TextView  android:text="界面"  android:layout_gravity="center"  android:layout_width="wrap_content"  android:layout_height="wrap_content" /></LinearLayout>

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="center" > <TextView  android:text="主界面"  android:layout_gravity="center"  android:layout_width="wrap_content"  android:layout_height="wrap_content" /></RelativeLayout>

<com.包名.myapplication.widget.DragLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/dl" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@android:color/transparent" > <!--下层 左边的布局 这个布局不能省去--> <include layout="@layout/one_frag_layout1"/> <!--上层 右边的主布局--> <com.包名.myapplication.widget.CustomRelativeLayout  android:layout_width="match_parent"  android:layout_height="match_parent"  android:background="#FFFFFF"  >  <LinearLayout   android:layout_width="fill_parent"   android:layout_height="fill_parent"   android:orientation="vertical"   >  <RelativeLayout   android:id="@+id/rl_title"   android:layout_width="match_parent"   android:layout_height="49dp"   android:gravity="bottom"   android:background="#2aaced"    >   <include layout="@layout/one_frag_layout"/>  </RelativeLayout>  <!--中间内容后面放入Fragment-->  <FrameLayout   android:layout_width="fill_parent"   android:layout_height="fill_parent"   >   <fragment    android:id="@+id/main_info_fragment"    class="com.mieasy.myapplication.OneFragment"    android:layout_width="fill_parent"    android:layout_height="fill_parent"/>  </FrameLayout>  </LinearLayout> </com.包名.myapplication.widget.CustomRelativeLayout></com.包名.myapplication.widget.DragLayout>