先看看效果：
首先，导入包：compile files('libs/nineoldandroids-2.4.0.jar')
r然后在main中创建一个widget包。
c创建ViewDragHelper类
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; } }
DragLayout布局继承FrameLayout：
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); } } }
CustomRelativeLayout：
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); } }
c沉浸式状态栏：BaseActivity：
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; } }
MainActivity：
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) { } }); } }
OneFragment：
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; } }
b布局文件：
one_frag_layout.xml
LinearLayout布局
<"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>
one_frag_layout1.xml:
RelativeLayout布局
<"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>
activity.main.xml:
<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" > <> <include layout="@layout/one_frag_layout1"/> <> <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> <> <FrameLayout android:layout_width="fill_parent" android:layout_height="fill_parent" > <fragment android:id="@+id/main_info_fragment" android:layout_width="fill_parent" android:layout_height="fill_parent"/> </FrameLayout> </LinearLayout> </com.包名.myapplication.widget.CustomRelativeLayout> </com.包名.myapplication.widget.DragLayout>
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持查字典教程网。
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