public static final int EDGE_TYPE_INSIDE = 0

Edge type that specifies an activation area starting at the view bounds and extending inward. Moving outside the view bounds will stop scrolling.

public static final int EDGE_TYPE_INSIDE_EXTEND = 1

Edge type that specifies an activation area starting at the view bounds and extending inward. After activation begins, moving outside the view bounds will continue scrolling.

public static final int EDGE_TYPE_OUTSIDE = 2

Edge type that specifies an activation area starting at the view bounds and extending outward. Moving inside the view bounds will stop scrolling.

public static final float NO_MAX = 3.4028235E38f

Constant passed to setMaximumEdges, setMaximumVelocity, or setMinimumVelocity. Using this value ensures that the computed relative value is always used without constraining to a particular minimum or maximum value.

public static final float NO_MIN = 0.0f

Constant passed to setMaximumEdges, or setMaximumVelocity, or setMinimumVelocity. Using this value ensures that the computed relative value is always used without constraining to a particular minimum or maximum value.

public static final float RELATIVE_UNSPECIFIED = 0.0f

Constant passed to setRelativeEdges or setRelativeVelocity. Using this value ensures that the computed relative value is ignored and the absolute maximum value is always used.

public AutoScrollHelper(@NonNull View target)

Creates a new helper for scrolling the specified target view.

The resulting helper may be configured by chaining setter calls and should be set as a touch listener on the target view.

By default, the helper is disabled and will not respond to touch events until it is enabled using setEnabled.

public abstract boolean canTargetScrollHorizontally(int direction)

Override this method to return whether the target view can be scrolled horizontally in a certain direction.

public abstract boolean canTargetScrollVertically(int direction)

Override this method to return whether the target view can be scrolled vertically in a certain direction.

public boolean isExclusive()

Indicates whether the scroll helper handles touch events exclusively during scrolling.

public boolean onTouch(View v, MotionEvent event)

Handles touch events by activating automatic scrolling, adjusting scroll velocity, or stopping.

If isExclusive is false, always returns false so that the host view may handle touch events. Otherwise, returns true when automatic scrolling is active and false otherwise.

public abstract void scrollTargetBy(int deltaX, int deltaY)

Override this method to scroll the target view by the specified number of pixels.

public @NonNull AutoScrollHelper setActivationDelay(int delayMillis)

Sets the delay after entering an activation edge before activation of auto-scrolling. By default, the activation delay is set to getTapTimeout.

Specifying a delay of zero will start auto-scrolling immediately after the touch position enters an activation edge.

public @NonNull AutoScrollHelper setEdgeType(int type)

Sets the activation edge type, one of:

• EDGE_TYPE_INSIDE for edges that respond to touches inside the bounds of the host view. If touch moves outside the bounds, scrolling will stop.
• EDGE_TYPE_INSIDE_EXTEND for inside edges that continued to scroll when touch moves outside the bounds of the host view.
• EDGE_TYPE_OUTSIDE for edges that only respond to touches that move outside the bounds of the host view.

public AutoScrollHelper setEnabled(boolean enabled)

Sets whether the scroll helper is enabled and should respond to touch events.

public AutoScrollHelper setExclusive(boolean exclusive)

Enables or disables exclusive handling of touch events during scrolling. By default, exclusive handling is disabled and the target view receives all touch events.

When enabled, onTouch will return true if the helper is currently scrolling and false otherwise.

public @NonNull AutoScrollHelper setMaximumEdges(float horizontalMax, float verticalMax)

Sets the absolute maximum edge size.

If relative edge size is not specified, activation edges will always be the maximum edge size. If both relative and maximum edges are specified, the maximum edge will be used to constrain the calculated relative edge size.

public @NonNull AutoScrollHelper setMaximumVelocity(float horizontalMax, float verticalMax)

Sets the absolute maximum scrolling velocity.

If relative velocity is not specified, scrolling will always reach the same maximum velocity. If both relative and maximum velocities are specified, the maximum velocity will be used to clamp the calculated relative velocity.

public @NonNull AutoScrollHelper setMinimumVelocity(float horizontalMin, float verticalMin)

Sets the absolute minimum scrolling velocity.

If both relative and minimum velocities are specified, the minimum velocity will be used to clamp the calculated relative velocity.

public @NonNull AutoScrollHelper setRampDownDuration(int durationMillis)

Sets the amount of time after de-activation of auto-scrolling that is takes to slow to a stop.

Specifying a duration greater than zero prevents sudden jumps in velocity.

public @NonNull AutoScrollHelper setRampUpDuration(int durationMillis)

Sets the amount of time after activation of auto-scrolling that is takes to reach target velocity for the current touch position.

Specifying a duration greater than zero prevents sudden jumps in velocity.

public @NonNull AutoScrollHelper setRelativeEdges(float horizontal, float vertical)

Sets the activation edge size relative to the host view's dimensions.

If both relative and maximum edges are specified, the maximum edge will be used to constrain the calculated relative edge size.

public @NonNull AutoScrollHelper setRelativeVelocity(float horizontal, float vertical)

Sets the target scrolling velocity relative to the host view's dimensions.

If both relative and maximum velocities are specified, the maximum velocity will be used to clamp the calculated relative velocity.