EDGE_TYPE_INSIDE

int EDGE_TYPE_INSIDE

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

Constant Value: 0 (0x00000000)

EDGE_TYPE_INSIDE_EXTEND

int EDGE_TYPE_INSIDE_EXTEND

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.

Constant Value: 1 (0x00000001)

EDGE_TYPE_OUTSIDE

int EDGE_TYPE_OUTSIDE

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

Constant Value: 2 (0x00000002)

NO_MAX

float NO_MAX

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

Constant Value: 3.4028235E38

NO_MIN

float NO_MIN

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

Constant Value: 0.0

RELATIVE_UNSPECIFIED

float RELATIVE_UNSPECIFIED

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

Constant Value: 0.0

AutoScrollHelper

AutoScrollHelper (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(boolean).

canTargetScrollHorizontally

boolean canTargetScrollHorizontally (int direction)

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

canTargetScrollVertically

boolean canTargetScrollVertically (int direction)

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

isEnabled

boolean isEnabled ()

isExclusive

boolean isExclusive ()

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

onTouch

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.

scrollTargetBy

void scrollTargetBy (int deltaX, 
                int deltaY)

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

setActivationDelay

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.

setEdgeType

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.

setEnabled

AutoScrollHelper setEnabled (boolean enabled)

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

setExclusive

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(View, MotionEvent) will return true if the helper is currently scrolling and false otherwise.

setMaximumEdges

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.

setMaximumVelocity

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.

setMinimumVelocity

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.

setRampDownDuration

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.

setRampUpDuration

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.

setRelativeEdges

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.

setRelativeVelocity

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.