Android轻松画出触摸轨迹

package com.android.gameview5;import android.app.Activity;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Path;import android.os.Bundle;import android.view.MotionEvent;import android.view.SurfaceHolder;import android.view.SurfaceHolder.Callback;import android.view.SurfaceView;import android.view.Window;import android.view.WindowManager;public class SurfaceViewActivity3 extends Activity {  public void onCreate(Bundle s){  super.onCreate(s);  //全屏显示  requestWindowFeature(Window.FEATURE_NO_TITLE);  getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,  WindowManager.LayoutParams.FLAG_FULLSCREEN);  setContentView(new MyView(this));  }  public class MyView extends SurfaceView implements Callback,Runnable{    public static final int TIME_IN_FRAME =50;    Paint mPaint = null;  Paint mTextPaint = null;  SurfaceHolder mSurfaceHolder = null;      boolean mRunning = false;      Canvas mCanvas = null;      private Path mPath;    private float mPosX,mPosY;  public MyView(Context context){super(context);this.setFocusable(true);this.setFocusableInTouchMode(true);  mSurfaceHolder = this.getHolder();  mSurfaceHolder.addCallback(this);  mCanvas = new Canvas();        mPaint = new Paint();  mPaint.setColor(Color.BLACK);      mPaint.setAntiAlias(true);    mPaint.setStyle(Paint.Style.STROKE);      mPaint.setStrokeCap(Paint.Cap.ROUND);      mPaint.setStrokeWidth(6);    mPath = new Path();      mTextPaint = new Paint();    mTextPaint.setColor(Color.BLACK);    mTextPaint.setTextSize(15);  }public boolean onTouchEvent(MotionEvent event){  int action = event.getAction();  float x = event.getX();  float y = event.getY();  switch(action){  case MotionEvent.ACTION_DOWN:  mPath.moveTo(x, y);  break;  case MotionEvent.ACTION_MOVE:  mPath.quadTo(mPosX, mPosY, x, y);  break;  case MotionEvent.ACTION_UP:  //mPath.reset();  break;  }  //记录当前触摸点得当前得坐标  mPosX = x;  mPosY = y;return true;}private void onDraw(){mCanvas.drawColor(Color.WHITE);//绘制曲线mCanvas.drawPath(mPath, mPaint);mCanvas.drawText("当前触笔X："+mPosX,0,20,mTextPaint);mCanvas.drawText("当前触笔Y:"+mPosY,0,40,mTextPaint);}public void run() {// TODO Auto-generated method stubwhile(mRunning){long startTime = System.currentTimeMillis();synchronized(mSurfaceHolder){mCanvas = mSurfaceHolder.lockCanvas();onDraw();mSurfaceHolder.unlockCanvasAndPost(mCanvas);}long endTime = System.currentTimeMillis();int diffTime = (int) (endTime - startTime);while(diffTime<=TIME_IN_FRAME){diffTime =(int)(System.currentTimeMillis()-startTime);Thread.yield();}}}@Overridepublic void surfaceChanged(SurfaceHolder holder, int format, int width,int height) {// TODO Auto-generated method stub}@Overridepublic void surfaceCreated(SurfaceHolder holder) {mRunning = true;new Thread(this).start();}@Overridepublic void surfaceDestroyed(SurfaceHolder holder) {// TODO Auto-generated method stubmRunning = false;}    }}