```
public class ScaleGestureDetector

                    
```
Detects scaling transformation gestures using the supplied MotionEvents. The OnScaleGestureListener callback will notify users when a particular gesture event has occurred. This class should only be used with MotionEvents reported via touch. To use this class:
- Create an instance of the {@code ScaleGestureDetector} for your View
- In the onTouchEvent method ensure you call onTouchEvent. The methods defined in your callback will be executed when the events occur.

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`public interface`	`ScaleGestureDetector.OnScaleGestureListener`	The listener for receiving notifications when gestures occur.If you want to listen for all the different gestures then implementthis interface. If you only want to listen for a subset it mightbe easier to extend SimpleOnScaleGestureListener.An application will receive events in the following order: One onScaleBegin Zero or more onScale One onScaleEnd
`public class`	`ScaleGestureDetector.SimpleOnScaleGestureListener`	A convenience class to extend when you only want to listen for a subsetof scaling-related events. This implements all methods in OnScaleGestureListener but does nothing. onScale returns `{@code false}` so that a subclass can retrieve the accumulated scalefactor in an overridden onScaleEnd. onScaleBegin returns `{@code true}`.

Constructor Summary

Constructors
Constructor	Description
`ScaleGestureDetector(Context context, ScaleGestureDetector.OnScaleGestureListener listener)`	Creates a ScaleGestureDetector with the supplied listener.
`ScaleGestureDetector(Context context, ScaleGestureDetector.OnScaleGestureListener listener, Handler handler)`	Creates a ScaleGestureDetector with the supplied listener.

Method Summary

Modifier and Type	Method	Description
`boolean`	`onTouchEvent(MotionEvent event)`	Accepts MotionEvents and dispatches events to a OnScaleGestureListener when appropriate.
`void`	`setQuickScaleEnabled(boolean scales)`	Set whether the associated OnScaleGestureListener should receive onScale callbackswhen the user performs a doubleTap followed by a swipe.
`boolean`	`isQuickScaleEnabled()`	Return whether the quick scale gesture, in which the user performs a double tap followed by aswipe, should perform scaling.
`void`	`setStylusScaleEnabled(boolean scales)`	Sets whether the associates OnScaleGestureListener should receiveonScale callbacks when the user uses a stylus and presses the button.Note that this is enabled by default if the app targets API 23 and newer.
`boolean`	`isStylusScaleEnabled()`	Return whether the stylus scale gesture, in which the user uses a stylus and presses thebutton, should perform scaling.
`boolean`	`isInProgress()`	Returns `{@code true}` if a scale gesture is in progress.
`float`	`getFocusX()`	Get the X coordinate of the current gesture's focal point.If a gesture is in progress, the focal point is betweeneach of the pointers forming the gesture.
`float`	`getFocusY()`	Get the Y coordinate of the current gesture's focal point.If a gesture is in progress, the focal point is betweeneach of the pointers forming the gesture.
`float`	`getCurrentSpan()`	Return the average distance between each of the pointers forming thegesture in progress through the focal point.
`float`	`getCurrentSpanX()`	Return the average X distance between each of the pointers forming thegesture in progress through the focal point.
`float`	`getCurrentSpanY()`	Return the average Y distance between each of the pointers forming thegesture in progress through the focal point.
`float`	`getPreviousSpan()`	Return the previous average distance between each of the pointers forming thegesture in progress through the focal point.
`float`	`getPreviousSpanX()`	Return the previous average X distance between each of the pointers forming thegesture in progress through the focal point.
`float`	`getPreviousSpanY()`	Return the previous average Y distance between each of the pointers forming thegesture in progress through the focal point.
`float`	`getScaleFactor()`	Return the scaling factor from the previous scale event to the currentevent.
`long`	`getTimeDelta()`	Return the time difference in milliseconds between the previousaccepted scaling event and the current scaling event.
`long`	`getEventTime()`	Return the event time of the current event being processed.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - ScaleGestureDetector
```
ScaleGestureDetector(Context context, ScaleGestureDetector.OnScaleGestureListener listener)
```
    Creates a ScaleGestureDetector with the supplied listener.
    
    Parameters:
    
    context - the application's context
    
    listener - the listener invoked for all the callbacks, this mustnot be null.
  - ScaleGestureDetector
```
ScaleGestureDetector(Context context, ScaleGestureDetector.OnScaleGestureListener listener, Handler handler)
```
    Creates a ScaleGestureDetector with the supplied listener.
    
    Parameters:
    
    context - the application's context
    
    listener - the listener invoked for all the callbacks, this mustnot be null.
    
    handler - the handler to use for running deferred listener events.
- Method Detail
  - onTouchEvent
```
 boolean onTouchEvent(MotionEvent event)
```
    Accepts MotionEvents and dispatches events to a OnScaleGestureListener when appropriate.
    Applications should pass a complete and consistent event stream to this method.A complete and consistent event stream involves all MotionEvents from the initialACTION_DOWN to the final ACTION_UP or ACTION_CANCEL.
    
    Parameters:
    
    event - The event to process
  - setQuickScaleEnabled
```
 void setQuickScaleEnabled(boolean scales)
```
    Set whether the associated OnScaleGestureListener should receive onScale callbackswhen the user performs a doubleTap followed by a swipe. Note that this is enabled by defaultif the app targets API 19 and newer.
    
    Parameters:
    
    scales - true to enable quick scaling, false to disable
  - isQuickScaleEnabled
```
 boolean isQuickScaleEnabled()
```
    Return whether the quick scale gesture, in which the user performs a double tap followed by aswipe, should perform scaling. {@see #setQuickScaleEnabled(boolean)}.
  - setStylusScaleEnabled
```
 void setStylusScaleEnabled(boolean scales)
```
    Sets whether the associates OnScaleGestureListener should receiveonScale callbacks when the user uses a stylus and presses the button.Note that this is enabled by default if the app targets API 23 and newer.
    
    Parameters:
    
    scales - true to enable stylus scaling, false to disable.
  - isStylusScaleEnabled
```
 boolean isStylusScaleEnabled()
```
    Return whether the stylus scale gesture, in which the user uses a stylus and presses thebutton, should perform scaling. {@see #setStylusScaleEnabled(boolean)}
  - isInProgress
```
 boolean isInProgress()
```
    Returns {@code true} if a scale gesture is in progress.
  - getFocusX
```
 float getFocusX()
```
    Get the X coordinate of the current gesture's focal point.If a gesture is in progress, the focal point is betweeneach of the pointers forming the gesture.If isInProgress would return false, the result of thisfunction is undefined.
  - getFocusY
```
 float getFocusY()
```
    Get the Y coordinate of the current gesture's focal point.If a gesture is in progress, the focal point is betweeneach of the pointers forming the gesture.If isInProgress would return false, the result of thisfunction is undefined.
  - getCurrentSpan
```
 float getCurrentSpan()
```
    Return the average distance between each of the pointers forming thegesture in progress through the focal point.
  - getCurrentSpanX
```
 float getCurrentSpanX()
```
    Return the average X distance between each of the pointers forming thegesture in progress through the focal point.
  - getCurrentSpanY
```
 float getCurrentSpanY()
```
    Return the average Y distance between each of the pointers forming thegesture in progress through the focal point.
  - getPreviousSpan
```
 float getPreviousSpan()
```
    Return the previous average distance between each of the pointers forming thegesture in progress through the focal point.
  - getPreviousSpanX
```
 float getPreviousSpanX()
```
    Return the previous average X distance between each of the pointers forming thegesture in progress through the focal point.
  - getPreviousSpanY
```
 float getPreviousSpanY()
```
    Return the previous average Y distance between each of the pointers forming thegesture in progress through the focal point.
  - getScaleFactor
```
 float getScaleFactor()
```
    Return the scaling factor from the previous scale event to the currentevent. This value is defined as(getCurrentSpan / getPreviousSpan).
  - getTimeDelta
```
 long getTimeDelta()
```
    Return the time difference in milliseconds between the previousaccepted scaling event and the current scaling event.
  - getEventTime
```
 long getEventTime()
```
    Return the event time of the current event being processed.

Class ScaleGestureDetector

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

ScaleGestureDetector

ScaleGestureDetector

Method Detail

onTouchEvent

setQuickScaleEnabled

isQuickScaleEnabled

setStylusScaleEnabled

isStylusScaleEnabled

isInProgress

getFocusX

getFocusY

getCurrentSpan

getCurrentSpanX

getCurrentSpanY

getPreviousSpan

getPreviousSpanX

getPreviousSpanY

getScaleFactor

getTimeDelta

getEventTime