Method Detail

• create

   static ViewDragHelper create(@NonNull() ViewGroup forParent, @NonNull() ViewDragHelper.Callback cb)

  Factory method to create a new ViewDragHelper.

  Parameters:

  forParent - Parent view to monitor

  cb - Callback to provide information and receive events

• create

   static ViewDragHelper create(@NonNull() ViewGroup forParent, float sensitivity, @NonNull() ViewDragHelper.Callback cb)

  Factory method to create a new ViewDragHelper.

  Parameters:

  forParent - Parent view to monitor

  sensitivity - Multiplier for how sensitive the helper should be about detectingthe start of a drag.

  cb - Callback to provide information and receive events

• setMinVelocity

   void setMinVelocity(float minVel)

  Set the minimum velocity that will be detected as having a magnitude greater than zeroin pixels per second. Callback methods accepting a velocity will be clamped appropriately.

  Parameters:

  minVel - Minimum velocity to detect

• getMinVelocity

   float getMinVelocity()

  Return the currently configured minimum velocity. Any flings with a magnitude lessthan this value in pixels per second. Callback methods accepting a velocity will receivezero as a velocity value if the real detected velocity was below this threshold.

• getViewDragState

   int getViewDragState()

  Retrieve the current drag state of this helper. This will return one of STATE_IDLE, STATE_DRAGGING or STATE_SETTLING.

• setEdgeTrackingEnabled

   void setEdgeTrackingEnabled(int edgeFlags)

  Enable edge tracking for the selected edges of the parent view.The callback's onEdgeTouched and onEdgeDragStarted methods will only be invokedfor edges for which edge tracking has been enabled.

  Parameters:

  edgeFlags - Combination of edge flags describing the edges to watch

• getEdgeSize

  @Px() int getEdgeSize()

  Return the size of an edge. This is the range in pixels along the edges of this viewthat will actively detect edge touches or drags if edge tracking is enabled.

• setEdgeSize

   void setEdgeSize(@Px() int size)

  Set the range in pixels along the edges of this view that will activelydetect edge touches or drags if edge tracking is enabled.

  Parameters:

  size - Edge size in pixels

• getDefaultEdgeSize

  @Px() int getDefaultEdgeSize()

  Return the default size used for edge tracking.

• captureChildView

   void captureChildView(@NonNull() View childView, int activePointerId)

  Capture a specific child view for dragging within the parent. The callback will be notifiedbut tryCaptureView will not be asked permission tocapture this view.

  Parameters:

  childView - Child view to capture

  activePointerId - ID of the pointer that is dragging the captured child view

• getCapturedView

  @Nullable() View getCapturedView()

• getActivePointerId

   int getActivePointerId()

• getTouchSlop

  @Px() int getTouchSlop()

• cancel

   void cancel()

  The result of a call to this method is equivalent to processTouchEvent receiving an ACTION_CANCEL event.

• abort

   void abort()

  cancel, but also abort all motion in progress and snap to the end of anyanimation.

• smoothSlideViewTo

   boolean smoothSlideViewTo(@NonNull() View child, int finalLeft, int finalTop)

  Animate the view child to the given (left, top) position.If this method returns true, the caller should invoke continueSettling on each subsequent frame to continue the motion until it returns false. If this methodreturns false there is no further work to do to complete the movement.

  This operation does not count as a capture event, though getCapturedView will still report the sliding view while the slide is in progress.

  Parameters:

  child - Child view to capture and animate

  finalLeft - Final left position of child

  finalTop - Final top position of child

• settleCapturedViewAt

   boolean settleCapturedViewAt(int finalLeft, int finalTop)

  Settle the captured view at the given (left, top) position.The appropriate velocity from prior motion will be taken into account.If this method returns true, the caller should invoke continueSettling on each subsequent frame to continue the motion until it returns false. If this methodreturns false there is no further work to do to complete the movement.

  Parameters:

  finalLeft - Settled left edge position for the captured view

  finalTop - Settled top edge position for the captured view

• flingCapturedView

   void flingCapturedView(int minLeft, int minTop, int maxLeft, int maxTop)

  Settle the captured view based on standard free-moving fling behavior.The caller should invoke continueSettling on each subsequent frameto continue the motion until it returns false.

  Parameters:

  minLeft - Minimum X position for the view's left edge

  minTop - Minimum Y position for the view's top edge

  maxLeft - Maximum X position for the view's left edge

  maxTop - Maximum Y position for the view's top edge

• continueSettling

   boolean continueSettling(boolean deferCallbacks)

  Move the captured settling view by the appropriate amount for the current time.If continueSettling returns true, the caller should call it againon the next frame to continue.

  Parameters:

  deferCallbacks - true if state callbacks should be deferred via posted message.

• isPointerDown

   boolean isPointerDown(int pointerId)

  Check if the given pointer ID represents a pointer that is currently down (to the bestof the ViewDragHelper's knowledge).

  The state used to report this information is populated by the methods shouldInterceptTouchEvent or processTouchEvent. If one of these methods has notbeen called for all relevant MotionEvents to track, the information reportedby this method may be stale or incorrect.

  Parameters:

  pointerId - pointer ID to check; corresponds to IDs provided by MotionEvent

• shouldInterceptTouchEvent

   boolean shouldInterceptTouchEvent(@NonNull() MotionEvent ev)

  Check if this event as provided to the parent view's onInterceptTouchEvent shouldcause the parent to intercept the touch event stream.

  Parameters:

  ev - MotionEvent provided to onInterceptTouchEvent

• processTouchEvent

   void processTouchEvent(@NonNull() MotionEvent ev)

  Process a touch event received by the parent view. This method will dispatch callback eventsas needed before returning. The parent view's onTouchEvent implementation should call this.

  Parameters:

  ev - The touch event received by the parent view

• checkTouchSlop

   boolean checkTouchSlop(int directions)

  Check if any pointer tracked in the current gesture has crossedthe required slop threshold.

  This depends on internal state populated by shouldInterceptTouchEvent or processTouchEvent. You should only rely onthe results of this method after all currently available touch datahas been provided to one of these two methods.

  Parameters:

  directions - Combination of direction flags, see DIRECTION_HORIZONTAL,DIRECTION_VERTICAL, DIRECTION_ALL

• checkTouchSlop

   boolean checkTouchSlop(int directions, int pointerId)

  Check if the specified pointer tracked in the current gesture has crossedthe required slop threshold.

  This depends on internal state populated by shouldInterceptTouchEvent or processTouchEvent. You should only rely onthe results of this method after all currently available touch datahas been provided to one of these two methods.

  Parameters:

  directions - Combination of direction flags, see DIRECTION_HORIZONTAL,DIRECTION_VERTICAL, DIRECTION_ALL

  pointerId - ID of the pointer to slop check as specified by MotionEvent

• isEdgeTouched

   boolean isEdgeTouched(int edges)

  Check if any of the edges specified were initially touched in the currently active gesture.If there is no currently active gesture this method will return false.

  Parameters:

  edges - Edges to check for an initial edge touch.

• isEdgeTouched

   boolean isEdgeTouched(int edges, int pointerId)

  Check if any of the edges specified were initially touched by the pointer withthe specified ID. If there is no currently active gesture or if there is no pointer withthe given ID currently down this method will return false.

  Parameters:

  edges - Edges to check for an initial edge touch.

• isCapturedViewUnder

   boolean isCapturedViewUnder(int x, int y)

  Determine if the currently captured view is under the given point in theparent view's coordinate system. If there is no captured view this methodwill return false.

  Parameters:

  x - X position to test in the parent's coordinate system

  y - Y position to test in the parent's coordinate system

• isViewUnder

   boolean isViewUnder(@Nullable() View view, int x, int y)

  Determine if the supplied view is under the given point in theparent view's coordinate system.

  Parameters:

  view - Child view of the parent to hit test

  x - X position to test in the parent's coordinate system

  y - Y position to test in the parent's coordinate system

• findTopChildUnder

  @Nullable() View findTopChildUnder(int x, int y)

  Find the topmost child under the given point within the parent view's coordinate system.The child order is determined using getOrderedChildIndex.

  Parameters:

  x - X position to test in the parent's coordinate system

  y - Y position to test in the parent's coordinate system