首页 / 移动开发 / Android / Android轻松画出触摸轨迹

实现代码：

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;}}}