customview/androidx.customview.widget/[main]ViewDragHelper

ViewDragHelper

(SESL variant) ViewDragHelper is a utility class for writing custom ViewGroups. It offers a number of useful operations and state tracking for allowing a user to drag and reposition views within their parent ViewGroup.

Types

Callback

abstract class Callback

A Callback is used as a communication channel with the ViewDragHelper back to the parent view using it.

Properties

DIRECTION_ALL

val DIRECTION_ALL: Int = 3

Indicates that a check should occur along all axes

DIRECTION_HORIZONTAL

val DIRECTION_HORIZONTAL: Int = 1

Indicates that a check should occur along the horizontal axis

DIRECTION_VERTICAL

val DIRECTION_VERTICAL: Int = 2

Indicates that a check should occur along the vertical axis

EDGE_ALL

val EDGE_ALL: Int = 15

Edge flag set indicating all edges should be affected.

EDGE_BOTTOM

val EDGE_BOTTOM: Int = 8

Edge flag indicating that the bottom edge should be affected.

EDGE_LEFT

val EDGE_LEFT: Int = 1

Edge flag indicating that the left edge should be affected.

EDGE_RIGHT

val EDGE_RIGHT: Int = 2

Edge flag indicating that the right edge should be affected.

EDGE_TOP

val EDGE_TOP: Int = 4

Edge flag indicating that the top edge should be affected.

INVALID_POINTER

val INVALID_POINTER: Int = -1

A null/invalid pointer ID.

STATE_DRAGGING

val STATE_DRAGGING: Int = 1

A view is currently being dragged.

STATE_IDLE

val STATE_IDLE: Int = 0

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

STATE_SETTLING

val STATE_SETTLING: Int = 2

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

Functions

abort

open fun abort()

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

cancel

open fun cancel()

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

captureChildView

open fun captureChildView(@NonNull childView: @NonNull View, activePointerId: Int)

Capture a specific child view for dragging within the parent.

checkTouchSlop

open fun checkTouchSlop(directions: Int): Boolean

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

open fun checkTouchSlop(directions: Int, pointerId: Int): Boolean

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

continueSettling

open fun continueSettling(deferCallbacks: Boolean): Boolean

Move the captured settling view by the appropriate amount for the current time.

create

@NonNull

open fun create(@NonNull forParent: @NonNull ViewGroup, @NonNull cb: @NonNull ViewDragHelper.Callback): @NonNull ViewDragHelper

@NonNull

open fun create(@NonNull forParent: @NonNull ViewGroup, sensitivity: Float, @NonNull cb: @NonNull ViewDragHelper.Callback): @NonNull ViewDragHelper

Factory method to create a new ViewDragHelper.

findTopChildUnder

@Nullable

open fun findTopChildUnder(x: Int, y: Int): @Nullable View

Find the topmost child under the given point within the parent view's coordinate system.

flingCapturedView

open fun flingCapturedView(minLeft: Int, minTop: Int, maxLeft: Int, maxTop: Int)

Settle the captured view based on standard free-moving fling behavior.

getActivePointerId

open fun getActivePointerId(): Int

getCapturedView

@Nullable

open fun getCapturedView(): @Nullable View

getDefaultEdgeSize

@Px

open fun getDefaultEdgeSize(): Int

Return the default size used for edge tracking.

getEdgeSize

@Px

open fun getEdgeSize(): Int

Return the size of an edge.

getMinVelocity

open fun getMinVelocity(): Float

Return the currently configured minimum velocity.

getTouchSlop

@Px

open fun getTouchSlop(): Int

getViewDragState

open fun getViewDragState(): Int

Retrieve the current drag state of this helper.

isCapturedViewUnder

open fun isCapturedViewUnder(x: Int, y: Int): Boolean

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

isEdgeTouched

open fun isEdgeTouched(edges: Int): Boolean

Check if any of the edges specified were initially touched in the currently active gesture.

open fun isEdgeTouched(edges: Int, pointerId: Int): Boolean

Check if any of the edges specified were initially touched by the pointer with the specified ID.

isPointerDown

open fun isPointerDown(pointerId: Int): Boolean

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

isViewUnder

open fun isViewUnder(@Nullable view: @Nullable View, x: Int, y: Int): Boolean

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

processTouchEvent

open fun processTouchEvent(@NonNull ev: @NonNull MotionEvent)

Process a touch event received by the parent view.

seslCreate

@NonNull

open fun seslCreate(@NonNull forParent: @NonNull ViewGroup, sensitivity: Float, @NonNull cb: @NonNull ViewDragHelper.Callback): @NonNull ViewDragHelper

Factory method to create a new ViewDragHelper.

seslSetUpdateOffsetLR

open fun seslSetUpdateOffsetLR(update: Boolean)

Sets whether to update the left and right offsets of the captured view during dragging and settling.

setEdgeSize

open fun setEdgeSize(@Px @IntRange(from = 0) size: Int)

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

setEdgeTrackingEnabled

open fun setEdgeTrackingEnabled(edgeFlags: Int)

Enable edge tracking for the selected edges of the parent view.

setMinVelocity

open fun setMinVelocity(minVel: Float)

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

settleCapturedViewAt

open fun settleCapturedViewAt(finalLeft: Int, finalTop: Int): Boolean

Settle the captured view at the given (left, top) position.

setTouchSlop

@RestrictTo(value = LIBRARY_GROUP_PREFIX)

open fun setTouchSlop(touchSlop: Int)

shouldInterceptTouchEvent

open fun shouldInterceptTouchEvent(@NonNull ev: @NonNull MotionEvent): Boolean

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

smoothSlideViewTo

open fun smoothSlideViewTo(@NonNull child: @NonNull View, finalLeft: Int, finalTop: Int): Boolean

open fun smoothSlideViewTo(@NonNull child: @NonNull View, finalLeft: Int, finalTop: Int, duration: Int, @Nullable interpolator: @Nullable Interpolator): Boolean

Animate the view child to the given (left, top) position.