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 stub while(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(); } } } @Override public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) { // TODO Auto-generated method stub } @Override public void surfaceCreated(SurfaceHolder holder) { mRunning = true; new Thread(this).start(); } @Override public void surfaceDestroyed(SurfaceHolder holder) { // TODO Auto-generated method stub mRunning = false; } } }