com.bogdwellers.pinchtozoom

Class MultiTouchListener

java.lang.Object

com.bogdwellers.pinchtozoom.MultiTouchListener

All Implemented Interfaces:

android.view.View.OnTouchListener

Direct Known Subclasses:

ImageMatrixTouchHandler

public class MultiTouchListener
extends java.lang.Object
implements android.view.View.OnTouchListener

This class enables easy interpretation of multitouch gestures such as pinching, rotating etc.

TODO Implement convex hull algorithm (static method) TODO Implement touch grouping by evaluating touch proximity TODO Implement get touch numbers ordered by x- or y-axis alignment

Constructor Summary

Constructors

Constructor and Description
MultiTouchListener()

Method Summary

Modifier and Type	Method and Description
static float	angle(android.view.MotionEvent event, int pointerA, int pointerB, boolean isPointerAPivot) Calculates the angle between two points.
int	getId(int touchNo) Returns the pointer id for the given index of subsequent touch points.
java.lang.Integer[]	getIdArray(java.lang.Integer[] ids) Returns an array containing all pointer ids.
android.graphics.PointF	getStartPoint(int touchNo) Returns the start point for the given touch number (where the user initially pressed down).
int	getTouchCount() Returns the current amount of touch points.
boolean	isTouching() Indicates if one or more touches are currently in progress.
static void	midPoint(android.graphics.PointF point, android.view.MotionEvent event, int pointerA, int pointerB) Calculates the mid point between two pointers.
static void	midPoint(android.graphics.Point point, android.view.MotionEvent event, int pointerA, int pointerB) Calculates the mid point between two pointers.
boolean	onTouch(android.view.View view, android.view.MotionEvent event)
static float	pinchVelocity(android.view.MotionEvent event, int pointerA, int pointerB, long timeWindow) Calculates the pinch velocity for the last timeWindow milliseconds.
static void	point(android.graphics.Point point, android.view.MotionEvent event, int id)
static float	spacing(android.view.MotionEvent event, int pointerA, int pointerB) Calculates the space between two pointers.
static boolean	startedLower(android.graphics.PointF pointA, android.graphics.PointF pointB) Convenience method to determine whether starting point A has a lower y-axis value than starting point B.
void	updateStartPoints(android.view.MotionEvent event) Updates the start points with the current coordinate configuration.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MultiTouchListener

public MultiTouchListener()

Method Detail

onTouch

public boolean onTouch(android.view.View view,
                       android.view.MotionEvent event)

Specified by:

onTouch in interface android.view.View.OnTouchListener

getTouchCount

public int getTouchCount()

Returns the current amount of touch points.

Returns:

isTouching

public boolean isTouching()

Indicates if one or more touches are currently in progress.

Returns:

getId

public int getId(int touchNo)

Returns the pointer id for the given index of subsequent touch points.

Parameters:

touchNo -

Returns:

getStartPoint

public android.graphics.PointF getStartPoint(int touchNo)

Returns the start point for the given touch number (where the user initially pressed down).

Parameters:

touchNo -

Returns:

updateStartPoints

public void updateStartPoints(android.view.MotionEvent event)

Updates the start points with the current coordinate configuration.

Parameters:

event -

getIdArray

public java.lang.Integer[] getIdArray(java.lang.Integer[] ids)

Returns an array containing all pointer ids.

Parameters:

ids -

Returns:

point

public static final void point(android.graphics.Point point,
                               android.view.MotionEvent event,
                               int id)

Parameters:

point -

event -

id -

spacing

public static final float spacing(android.view.MotionEvent event,
                                  int pointerA,
                                  int pointerB)

Calculates the space between two pointers.

Parameters:

event -

pointerA - id of pointer A

pointerB - id of pointer B

Returns:

spacing between both pointers

pinchVelocity

public static final float pinchVelocity(android.view.MotionEvent event,
                                        int pointerA,
                                        int pointerB,
                                        long timeWindow)

Calculates the pinch velocity for the last timeWindow milliseconds.

Parameters:

event -

pointerA - id of pointer A

pointerB - id of pointer B

timeWindow -

Returns:

spacing between both pointers

midPoint

public static final void midPoint(android.graphics.Point point,
                                  android.view.MotionEvent event,
                                  int pointerA,
                                  int pointerB)

Calculates the mid point between two pointers.

Parameters:

point -

event -

pointerA - id of pointer A

pointerB - id of pointer B

midPoint

public static final void midPoint(android.graphics.PointF point,
                                  android.view.MotionEvent event,
                                  int pointerA,
                                  int pointerB)

Calculates the mid point between two pointers.

Parameters:

point -

event -

pointerA - id of pointer A

pointerB - id of pointer B

angle

public static final float angle(android.view.MotionEvent event,
                                int pointerA,
                                int pointerB,
                                boolean isPointerAPivot)

Calculates the angle between two points.

Parameters:

event -

pointerA - id of pointer A

pointerB - id of pointer B

isPointerAPivot - indicates if pointer A is considered to be the pivot, else pointer B is. Use startedLower(PointF, PointF)

Returns:

angle in degrees

startedLower

public static final boolean startedLower(android.graphics.PointF pointA,
                                         android.graphics.PointF pointB)

Convenience method to determine whether starting point A has a lower y-axis value than starting point B. Useful in conjunction with angle(MotionEvent, int, int, boolean).

Parameters:

pointA -

pointB -

Returns: