Android 不同手势的识别：滑动、放大缩小

Demo地址：http://download.csdn.net/detail/baopengjian/9670309一、需求：识别：单指 上滑、下滑、左移、右移、长按多指 放大、缩小、长按
二、实现：自定义View 通过onTouchEvent识别事件通过GestureListener识别长按
三、View：public class TouchModeView extends View {
public final static int NONE = 0;/**按下*/public final static int PRESS = 1;/**左移*/public final static int LEFT = 2;/**右移*/public final static int RIGHT = 3;/**上移*/public final static int UP = 4;/**下移*/public final static int DOWN = 5;/**长按*/public final static int LONG_PRESS = 6;/**放大*/public final static int AMPLIFICATION = 7;/**缩小*/public final static int NARROW = 8;
private static final float MIN_MOVE_DISTANCE = 15;
private int mTouchMode;private float mStartX,mStartY;private long mStartTime;private float mFingerSpace;
private GestureDetector mGestureDetector;
public TouchModeView(Context context) {super(context);init();}
public TouchModeView(Context context, AttributeSet attrs) {super(context, attrs);init();}
public TouchModeView(Context context, AttributeSet attrs, int defStyleAttr) {super(context, attrs, defStyleAttr);init();}
private void init() {mGestureDetector = new GestureDetector(getContext(), new MyGestureListener());}
interface Listener{public void getMode(int mode);}Listener mListener;public void setListener(Listener listener){mListener = listener;}
@Overridepublic boolean onTouchEvent(MotionEvent event) {switch (event.getAction() & MotionEvent.ACTION_MASK) {case MotionEvent.ACTION_DOWN:mGestureDetector.onTouchEvent(event);mTouchMode = PRESS;mStartX = event.getRawX();mStartY = event.getRawY();mStartTime = System.currentTimeMillis();mFingerSpace = 0;if(mListener !=null){mListener.getMode(mTouchMode);}break;case MotionEvent.ACTION_MOVE:getGestures(event);if(mListener !=null){mListener.getMode(mTouchMode);}break;case MotionEvent.ACTION_UP:case MotionEvent.ACTION_POINTER_UP:mTouchMode = NONE;if(mListener !=null){mListener.getMode(mTouchMode);}break;
case MotionEvent.ACTION_CANCEL:mTouchMode = NONE;if(mListener !=null){mListener.getMode(mTouchMode);}break;}return true;}

private void getGestures(MotionEvent event) {// 2个手指以上if (event.getPointerCount() >= 2){//先判断是否是缩放float x1 = event.getX(0) - event.getX(1);float y1 = event.getY(0) - event.getY(1);//第一个手指和第二个手指的间距float value = (float) Math.sqrt(x1 * x1 + y1 * y1);if(mFingerSpace == 0){mFingerSpace = value;}else{//一段时间内，如果两值间的变化不大，则认为是移动，否则是；加时间限制是为了防止反应过快if(System.currentTimeMillis() -mStartTime>50 ){//移动后两指的间距的变化值float fingerDistanceChange = value - mFingerSpace;//同时手指间的间距变化大于最小距离时就认为是缩放if(Math.abs(fingerDistanceChange)>MIN_MOVE_DISTANCE){float scale = value / mFingerSpace;if(scale>1){mTouchMode = AMPLIFICATION;}else{mTouchMode = NARROW;}mStartTime = System.currentTimeMillis();mStartX = event.getX();mStartY = event.getY();mFingerSpace = value;//当第一个手指200毫秒内移动MIN_MOVE_DISTANCE倍距离，同时手指间的间距变化小于4倍距离时为移动}}return;}}//判断是否长按,x方向移动小于最小距离同时y方向小于最小距离，float offsetX = Math.abs(event.getX() - mStartX);float offsetY = Math.abs(event.getY() - event.getY());long time = System.currentTimeMillis() - mStartTime;if(time>1500&& Math.abs(offsetX)<MIN_MOVE_DISTANCE&&Math.abs(offsetY)<MIN_MOVE_DISTANCE){mTouchMode = LONG_PRESS;return;}//移动时区分上下还是左右if(System.currentTimeMillis() -mStartTime>50){float xDistance = event.getX() - mStartX;float yDistance = event.getY()- mStartY;if(Math.abs(xDistance)>Math.abs(yDistance)){if(xDistance>0){mTouchMode = RIGHT;}else{mTouchMode = LEFT;}}else{if(yDistance>0){mTouchMode = DOWN;}else{mTouchMode = UP;}}mStartTime = System.currentTimeMillis();mStartX = event.getX();mStartY = event.getY();}}
class MyGestureListener extends SimpleOnGestureListener{@Overridepublic void onLongPress(MotionEvent e) {super.onLongPress(e);if(mTouchMode==AMPLIFICATION||mTouchMode==NARROW ){return;}mTouchMode = LONG_PRESS;if(mListener !=null){mListener.getMode(mTouchMode);}}}
}