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;
}
@Override
public 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)
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{
@Override
public void onLongPress(MotionEvent e) {
super.onLongPress(e);
if(mTouchMode==AMPLIFICATION||mTouchMode==NARROW ){
return;
}
mTouchMode = LONG_PRESS;
if(mListener !=null){
mListener.getMode(mTouchMode);
}
}
}
}