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)<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{

@Override

public void onLongPress(MotionEvent e) {

super.onLongPress(e);

if(mTouchMode==AMPLIFICATION||mTouchMode==NARROW ){

return;

}

mTouchMode = LONG_PRESS;

if(mListener !=null){

mListener.getMode(mTouchMode);

}

}

}

}