Package com.google.gwt.touch.client

Class TouchScroller

java.lang.Object
com.google.gwt.touch.client.TouchScroller
public class TouchScroller extends Object
Adds touch based scrolling to a scroll panel.

Touch based scrolling is only supported on devices that support touch events and do not implement native touch based scrolling.

  • Constructor Details

  • Method Details

    • createIfSupported

      public static TouchScroller createIfSupported()
      Return a new TouchScroller.
      Returns:
      a new TouchScroller if supported, and null otherwise

    • createIfSupported

      public static TouchScroller createIfSupported(HasScrolling widget)
      Return a new TouchScroller that augments the specified scrollable widget if supported, and null otherwise.
      Parameters:
      widget - the scrollable widget
      Returns:
      a new TouchScroller if supported, and null otherwise

    • isSupported

      public static boolean isSupported()
      Runtime check for whether touch scrolling is supported in this browser. Returns true if touch events are supported but touch based scrolling is not natively supported.
      Returns:
      true if touch scrolling is supported, false if not

    • getMomentum

      public Momentum getMomentum()
      Get the Momentum that controls scrolling after the user completes a gesture.
      Returns:
      the scrolling Momentum, or null if disabled

    • getTargetWidget

      public HasScrolling getTargetWidget()
      Get the target HasScrolling widget that this scroller affects.
      Returns:
      the target widget

    • setMomentum

      public void setMomentum(Momentum momentum)
      Set the Momentum that controls scrolling after the user completes a gesture.
      Parameters:
      momentum - the scrolling Momentum, or null to disable

    • setTargetWidget

      public void setTargetWidget(HasScrolling widget)
      Set the target HasScrolling widget that this scroller affects.
      Parameters:
      widget - the target widget, or null to disbale

    • getTouchFromEvent

      protected Touch getTouchFromEvent(TouchEvent<?> event)
      Get touch from event.
      Parameters:
      event - the event
      Returns:
      the touch object

    • onDragEnd

      protected void onDragEnd(TouchEvent<?> event)
      Called when the object's drag sequence is complete.
      Parameters:
      event - the touch event

    • onDragMove

      protected void onDragMove(TouchEvent<?> event)
      Called when the object has been dragged to a new position.
      Parameters:
      event - the touch event

    • onDragStart

      protected void onDragStart(TouchEvent<?> event)
      Called when the object has started dragging.
      Parameters:
      event - the touch event

    • onTouchCancel

      protected void onTouchCancel(TouchEvent<?> event)
      Called when the user cancels a touch. This can happen if the user touches the screen with too many fingers.
      Parameters:
      event - the touch event

    • onTouchEnd

      protected void onTouchEnd(TouchEvent<?> event)
      Called when the user releases a touch.
      Parameters:
      event - the touch event

    • onTouchMove

      protected void onTouchMove(TouchEvent<?> event)
      Called when the user moves a touch.
      Parameters:
      event - the touch event

    • onTouchStart

      protected void onTouchStart(TouchEvent<?> event)
      Called when the user starts a touch.
      Parameters:
      event - the touch event

    • calculateEndVelocity

      Point calculateEndVelocity(TouchScroller.TemporalPoint from, TouchScroller.TemporalPoint to)
      Calculate the end velocity. Visible for testing.
      Parameters:
      from - the starting point
      to - the ending point
      Returns:
      the end velocity, or null if it cannot be calculated

    • getLastTouchPosition

      TouchScroller.TemporalPoint getLastTouchPosition()
      Visible for testing.

    • getRecentTouchPosition

      TouchScroller.TemporalPoint getRecentTouchPosition()
      Visible for testing.

    • isDragging

      boolean isDragging()
      Visible for testing.

    • isMomentumActive

      boolean isMomentumActive()
      Check if momentum is currently active. Visible for testing.
      Returns:
      true if active, false if not

    • isTouching

      boolean isTouching()
      Visible for testing.

    • removeAttachHandler

      void removeAttachHandler()
      Removes the attach handler. Visible for testing.

    • removeBustClickHandler

      void removeBustClickHandler()
      Removes the bust click handler. Visible for testing.

    • setupBustClickHandler

      void setupBustClickHandler()
      Sets up the bust click handler. Visible for testing.