Method Detail

• onViewDragStateChanged

   void onViewDragStateChanged(int state)

  Called when the drag state changes. See the STATE_* constantsfor more information.

  Parameters:

  state - The new drag state

• onViewPositionChanged

   void onViewPositionChanged(@NonNull() View changedView, int left, int top, @Px() int dx, @Px() int dy)

  Called when the captured view's position changes as the result of a drag or settle.

  Parameters:

  changedView - View whose position changed

  left - New X coordinate of the left edge of the view

  top - New Y coordinate of the top edge of the view

  dx - Change in X position from the last call

  dy - Change in Y position from the last call

• onViewCaptured

   void onViewCaptured(@NonNull() View capturedChild, int activePointerId)

  Called when a child view is captured for dragging or settling. The ID of the pointercurrently dragging the captured view is supplied. If activePointerId isidentified as INVALID_POINTER the capture is programmatic instead ofpointer-initiated.

  Parameters:

  capturedChild - Child view that was captured

  activePointerId - Pointer id tracking the child capture

• onViewReleased

   void onViewReleased(@NonNull() View releasedChild, float xvel, float yvel)

  Called when the child view is no longer being actively dragged.The fling velocity is also supplied, if relevant. The velocity values maybe clamped to system minimums or maximums.

  Calling code may decide to fling or otherwise release the view to let itsettle into place. It should do so using settleCapturedViewAt or flingCapturedView. If the Callback invokesone of these methods, the ViewDragHelper will enter STATE_SETTLING and the view capture will not fully end until it comes to a complete stop.If neither of these methods is invoked before onViewReleased returns,the view will stop in place and the ViewDragHelper will return to STATE_IDLE.

  Parameters:

  releasedChild - The captured child view now being released

  xvel - X velocity of the pointer as it left the screen in pixels per second.

  yvel - Y velocity of the pointer as it left the screen in pixels per second.

• onEdgeTouched

   void onEdgeTouched(int edgeFlags, int pointerId)

  Called when one of the subscribed edges in the parent view has been touchedby the user while no child view is currently captured.

  Parameters:

  edgeFlags - A combination of edge flags describing the edge(s) currently touched

  pointerId - ID of the pointer touching the described edge(s)

• onEdgeLock

   boolean onEdgeLock(int edgeFlags)

  Called when the given edge may become locked. This can happen if an edge dragwas preliminarily rejected before beginning, but after onEdgeTouched was called. This method should return true to lock this edge or false to leave itunlocked. The default behavior is to leave edges unlocked.

  Parameters:

  edgeFlags - A combination of edge flags describing the edge(s) locked

• onEdgeDragStarted

   void onEdgeDragStarted(int edgeFlags, int pointerId)

  Called when the user has started a deliberate drag away from oneof the subscribed edges in the parent view while no child view is currently captured.

  Parameters:

  edgeFlags - A combination of edge flags describing the edge(s) dragged

  pointerId - ID of the pointer touching the described edge(s)

• getOrderedChildIndex

   int getOrderedChildIndex(int index)

  Called to determine the Z-order of child views.

  Parameters:

  index - the ordered position to query for

• getViewHorizontalDragRange

   int getViewHorizontalDragRange(@NonNull() View child)

  Return the magnitude of a draggable child view's horizontal range of motion in pixels.This method should return 0 for views that cannot move horizontally.

  Parameters:

  child - Child view to check

• getViewVerticalDragRange

   int getViewVerticalDragRange(@NonNull() View child)

  Return the magnitude of a draggable child view's vertical range of motion in pixels.This method should return 0 for views that cannot move vertically.

  Parameters:

  child - Child view to check

• tryCaptureView

   abstract boolean tryCaptureView(@NonNull() View child, int pointerId)

  Called when the user's input indicates that they want to capture the given child viewwith the pointer indicated by pointerId. The callback should return true if the useris permitted to drag the given view with the indicated pointer.

  ViewDragHelper may call this method multiple times for the same view even ifthe view is already captured; this indicates that a new pointer is trying to takecontrol of the view.

  If this method returns true, a call to onViewCaptured will follow if the capture is successful.

  Parameters:

  child - Child the user is attempting to capture

  pointerId - ID of the pointer attempting the capture

• clampViewPositionHorizontal

   int clampViewPositionHorizontal(@NonNull() View child, int left, int dx)

  Restrict the motion of the dragged child view along the horizontal axis.The default implementation does not allow horizontal motion; the extendingclass must override this method and provide the desired clamping.

  Parameters:

  child - Child view being dragged

  left - Attempted motion along the X axis

  dx - Proposed change in position for left

• clampViewPositionVertical

   int clampViewPositionVertical(@NonNull() View child, int top, int dy)

  Restrict the motion of the dragged child view along the vertical axis.The default implementation does not allow vertical motion; the extendingclass must override this method and provide the desired clamping.

  Parameters:

  child - Child view being dragged

  top - Attempted motion along the Y axis

  dy - Proposed change in position for top