ViewDragHelper

public static final int DIRECTION_ALL = 3

Indicates that a check should occur along all axes

public static final int DIRECTION_HORIZONTAL = 1

Indicates that a check should occur along the horizontal axis

public static final int DIRECTION_VERTICAL = 2

Indicates that a check should occur along the vertical axis

public static final int EDGE_ALL = 15

Edge flag set indicating all edges should be affected.

public static final int EDGE_BOTTOM = 8

Edge flag indicating that the bottom edge should be affected.

public static final int EDGE_LEFT = 1

Edge flag indicating that the left edge should be affected.

public static final int EDGE_RIGHT = 2

Edge flag indicating that the right edge should be affected.

public static final int EDGE_TOP = 4

Edge flag indicating that the top edge should be affected.

public static final int INVALID_POINTER = -1

A null/invalid pointer ID.

public static final int STATE_DRAGGING = 1

A view is currently being dragged. The position is currently changing as a result of user input or simulated user input.

public static final int STATE_IDLE = 0

A view is not currently being dragged or animating as a result of a fling/snap.

public static final int STATE_SETTLING = 2

A view is currently settling into place as a result of a fling or predefined non-interactive motion.

public void abort()

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

public void cancel()

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

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

Capture a specific child view for dragging within the parent. The callback will be notified but tryCaptureView will not be asked permission to capture this view.

public boolean checkTouchSlop(int directions)

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

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

public boolean checkTouchSlop(int directions, int pointerId)

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

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

public 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 again on the next frame to continue.

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

Factory method to create a new ViewDragHelper.

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

Factory method to create a new ViewDragHelper.

public @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.

public 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 frame to continue the motion until it returns false.

public int getActivePointerId()

public @Nullable View getCapturedView()

public @Px int getDefaultEdgeSize()

Return the default size used for edge tracking.

public @Px int getEdgeSize()

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

public float getMinVelocity()

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

public @Px int getTouchSlop()

public int getViewDragState()

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

public boolean isCapturedViewUnder(int x, int y)

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

public 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.

public boolean isEdgeTouched(int edges, int pointerId)

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

public boolean isPointerDown(int pointerId)

Check if the given pointer ID represents a pointer that is currently down (to the best of 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 not been called for all relevant MotionEvents to track, the information reported by this method may be stale or incorrect.

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

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

public void processTouchEvent(@NonNull MotionEvent ev)

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

public void setEdgeSize(@Px @IntRange(from = 0) int size)

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

public 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 invoked for edges for which edge tracking has been enabled.

public void setMinVelocity(float minVel)

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

public 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 method returns false there is no further work to do to complete the movement.

public boolean shouldInterceptTouchEvent(@NonNull MotionEvent ev)

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

public 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 method returns 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.

protected boolean canScroll(@NonNull View v, boolean checkV, int dx, int dy, int x, int y)

Tests scrollability within child views of v given a delta of dx.