Android APIs
Added in API level 8
public static interface

ScaleGestureDetector.OnScaleGestureListener

android.view.ScaleGestureDetector.OnScaleGestureListener
Known Indirect Subclasses

Class Overview

The listener for receiving notifications when gestures occur. If you want to listen for all the different gestures then implement this interface. If you only want to listen for a subset it might be easier to extend ScaleGestureDetector.SimpleOnScaleGestureListener. An application will receive events in the following order:

Summary

Public Methods
abstract boolean onScale(ScaleGestureDetector detector)
Responds to scaling events for a gesture in progress.
abstract boolean onScaleBegin(ScaleGestureDetector detector)
Responds to the beginning of a scaling gesture.
abstract void onScaleEnd(ScaleGestureDetector detector)
Responds to the end of a scale gesture.

Public Methods

public abstract boolean onScale (ScaleGestureDetector detector)

Added in API level 8

Responds to scaling events for a gesture in progress. Reported by pointer motion.

Parameters
detector ScaleGestureDetector: The detector reporting the event - use this to retrieve extended info about event state.
Returns
boolean Whether or not the detector should consider this event as handled. If an event was not handled, the detector will continue to accumulate movement until an event is handled. This can be useful if an application, for example, only wants to update scaling factors if the change is greater than 0.01.

public abstract boolean onScaleBegin (ScaleGestureDetector detector)

Added in API level 8

Responds to the beginning of a scaling gesture. Reported by new pointers going down.

Parameters
detector ScaleGestureDetector: The detector reporting the event - use this to retrieve extended info about event state.
Returns
boolean Whether or not the detector should continue recognizing this gesture. For example, if a gesture is beginning with a focal point outside of a region where it makes sense, onScaleBegin() may return false to ignore the rest of the gesture.

public abstract void onScaleEnd (ScaleGestureDetector detector)

Added in API level 8

Responds to the end of a scale gesture. Reported by existing pointers going up. Once a scale has ended, getFocusX() and getFocusY() will return focal point of the pointers remaining on the screen.

Parameters
detector ScaleGestureDetector: The detector reporting the event - use this to retrieve extended info about event state.