[Android实例] android多点触摸demo .

 

MultiTouchActivity

 package com.zhaokai.multitouch;
 import android.app.Activity;
 import android.os.Bundle;
 import android.view.Window;
 import android.view.WindowManager;

 public class MultiTouchActivity extends Activity {
     /** Called when the activity is first created. */
      /** Called when the activity is first created. */
     @Override
     public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       //隐藏标题栏
       requestWindowFeature(Window.FEATURE_NO_TITLE);
       //设置成全屏
       getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
       //设置为上面的MTView
       setContentView(new MySurfaceView(this));
     }
 }

SurfaceView类： 

 package com.zhaokai.multitouch;

 import android.content.Context;
 import android.graphics.Canvas;
 import android.graphics.Color;
 import android.graphics.Paint;
 import android.view.MotionEvent;
 import android.view.SurfaceHolder;
 import android.view.SurfaceHolder.Callback;
 import android.view.SurfaceView;
 public class MySurfaceView extends SurfaceView implements Callback{
 private static final int MAX_TOUCHPOINTS = 10;
 private static final String START_TEXT = "请随便触摸屏幕进行测试";
 private Paint textPaint = new Paint();
 private Paint touchPaints[] = new Paint[MAX_TOUCHPOINTS];
 private int colors[] = new int[MAX_TOUCHPOINTS];
 private int width, height;
 private float scale = 1.0f;

 public MySurfaceView(Context context) {
   super(context);
   SurfaceHolder holder = getHolder();
   holder.addCallback(this);
   setFocusable(true); // 确保我们的View能获得输入焦点
   setFocusableInTouchMode(true); // 确保能接收到触屏事件
   init();
 }
 public void init(){
   // 初始化10个不同颜色的画笔
   textPaint.setColor(Color.WHITE);
   colors[0] = Color.BLUE;
   colors[1] = Color.RED;
   colors[2] = Color.GREEN;
   colors[3] = Color.YELLOW;
   colors[4] = Color.CYAN;
   colors[5] = Color.MAGENTA;
   colors[6] = Color.DKGRAY;
   colors[7] = Color.WHITE;
   colors[8] = Color.LTGRAY;
   colors[9] = Color.GRAY;
   for(int i=0;i<MAX_TOUCHPOINTS;i++){
    touchPaints[i]=new Paint();
    touchPaints[i].setColor(colors[i]);
   }
 }

 @Override
 public boolean onTouchEvent(MotionEvent event) {
   int pointerCount=event.getPointerCount();
   if(pointerCount>MAX_TOUCHPOINTS){
    pointerCount=MAX_TOUCHPOINTS;
   }
   Canvas c=getHolder().lockCanvas();
   if(c!=null){
    c.drawColor(Color.BLACK);
    if(event.getAction()==MotionEvent.ACTION_UP){
     // 当手离开屏幕时，清屏
     c.drawColor(Color.BLACK);
    }else{
      // 先在屏幕上画一个十字，然后画一个圆
     for(int i=0;i<pointerCount;i++){
      //获取一个触点的坐标，然后开始绘制
      int id=event.getPointerId(i);
      int x=(int)event.getX(i);
      int y=(int)event.getY(i);
      drawCrosshairsAndText(x, y, touchPaints[id], i, id, c);
     }
     for(int i=0;i<pointerCount;i++){
      int id=event.getPointerId(i);
      int x=(int)event.getX(i);
      int y=(int)event.getY(i);
      drawCircle(x, y, touchPaints[id],c);
     }
    }
    getHolder().unlockCanvasAndPost(c);
   }
   return true;
 }

 private void drawCrosshairsAndText(int x, int y, Paint paint, int ptr,int id, Canvas c) {
   c.drawLine(0, y, width, y, paint);
   c.drawLine(x, 0, x, height, paint);
   int textY = (int) ((15 + 20 * ptr) * scale);
   c.drawText("x" + ptr + "=" + x, 10 * scale, textY, textPaint);
   c.drawText("y" + ptr + "=" + y, 70 * scale, textY, textPaint);
   c.drawText("id" + ptr + "=" + id, width - 55 * scale, textY, textPaint);
 }

 private void drawCircle(int x, int y, Paint paint, Canvas c) {
   c.drawCircle(x, y, 40 * scale, paint);
 }

 @Override
 public void surfaceChanged(SurfaceHolder holder, int format, int width,
    int height) {
    this.width = width;
    this.height = height;
    if (width > height){
     this.scale = width / 480f;
    } else {
    this.scale = height / 480f;
    }
    textPaint.setTextSize(14 * scale);
    Canvas c = getHolder().lockCanvas();
    if (c != null) {              // 背景黑色
     c.drawColor(Color.BLACK);
     float tWidth = textPaint.measureText(START_TEXT);
     c.drawText(START_TEXT, width / 2 - tWidth / 2, height / 2,textPaint);
     getHolder().unlockCanvasAndPost(c);
   }
 }
 @Override
 public void surfaceCreated(SurfaceHolder holder) {
   // TODO Auto-generated method stub

 }
 @Override
 public void surfaceDestroyed(SurfaceHolder holder) {
   // TODO Auto-generated method stub

 }

 }