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package com.almeros.android.multitouch.gesturedetectors;
import android.content.Context;
import android.view.MotionEvent;
/**
* @author Almer Thie (code.almeros.com) Copyright (c) 2013, Almer Thie
* (code.almeros.com)
* <p>
* All rights reserved.
* <p>
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* <p>
* Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* <p>
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
* WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
public class RotateGestureDetector extends TwoFingerGestureDetector {
/**
* Listener which must be implemented which is used by RotateGestureDetector
* to perform callbacks to any implementing class which is registered to a
* RotateGestureDetector via the constructor.
*
* @see RotateGestureDetector.SimpleOnRotateGestureListener
*/
public interface OnRotateGestureListener {
public boolean onRotate(RotateGestureDetector detector);
public boolean onRotateBegin(RotateGestureDetector detector);
public void onRotateEnd(RotateGestureDetector detector);
}
/**
* Helper class which may be extended and where the methods may be
* implemented. This way it is not necessary to implement all methods of
* OnRotateGestureListener.
*/
public static class SimpleOnRotateGestureListener implements
OnRotateGestureListener {
public boolean onRotate(RotateGestureDetector detector) {
return false;
}
public boolean onRotateBegin(RotateGestureDetector detector) {
return true;
}
public void onRotateEnd(RotateGestureDetector detector) {
// Do nothing, overridden implementation may be used
}
}
private final OnRotateGestureListener listener;
private boolean sloppyGesture;
public RotateGestureDetector(Context context,
OnRotateGestureListener listener) {
super(context);
this.listener = listener;
}
@Override
protected void handleStartProgressEvent(int actionCode, MotionEvent event) {
switch (actionCode) {
case MotionEvent.ACTION_POINTER_DOWN:
// At least the second finger is on screen now
resetState(); // In case we missed an UP/CANCEL event
prevEvent = MotionEvent.obtain(event);
timeDelta = 0;
updateStateByEvent(event);
// See if we have a sloppy gesture
sloppyGesture = isSloppyGesture(event);
if (!sloppyGesture) {
// No, start gesture now
gestureInProgress = listener.onRotateBegin(this);
}
break;
case MotionEvent.ACTION_MOVE:
if (!sloppyGesture) {
break;
}
// See if we still have a sloppy gesture
sloppyGesture = isSloppyGesture(event);
if (!sloppyGesture) {
// No, start normal gesture now
gestureInProgress = listener.onRotateBegin(this);
}
break;
case MotionEvent.ACTION_POINTER_UP:
if (!sloppyGesture) {
break;
}
break;
}
}
@Override
protected void handleInProgressEvent(int actionCode, MotionEvent event) {
switch (actionCode) {
case MotionEvent.ACTION_POINTER_UP:
// Gesture ended but
updateStateByEvent(event);
if (!sloppyGesture) {
listener.onRotateEnd(this);
}
resetState();
break;
case MotionEvent.ACTION_CANCEL:
if (!sloppyGesture) {
listener.onRotateEnd(this);
}
resetState();
break;
case MotionEvent.ACTION_MOVE:
updateStateByEvent(event);
// Only accept the event if our relative pressure is within
// a certain limit. This can help filter shaky data as a
// finger is lifted.
if (currPressure / prevPressure > PRESSURE_THRESHOLD) {
final boolean updatePrevious = listener.onRotate(this);
if (updatePrevious) {
prevEvent.recycle();
prevEvent = MotionEvent.obtain(event);
}
}
break;
}
}
@Override
protected void resetState() {
super.resetState();
sloppyGesture = false;
}
/**
* Return the rotation difference from the previous rotate event to the
* current event.
*
* @return The current rotation //difference in degrees.
*/
public float getRotationDegreesDelta() {
double diffRadians = Math.atan2(prevFingerDiffY, prevFingerDiffX)
- Math.atan2(currFingerDiffY, currFingerDiffX);
return (float) (diffRadians * 180.0 / Math.PI);
}
}
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