本文实例讲述了Android中SurfaceView用法。分享给大家供大家参考,具体如下:
这里贴上一个小程序代码,主要运用SurfaceView来实现在屏幕上画一个圆,你可以通过按方向键和触摸屏幕来改变圆的位置
代码:
Activity:
package com.view; import android.app.Activity; import android.os.Bundle; import android.view.Window; import android.view.WindowManager; public class MainActivity extends Activity {/** Called when the activity is first created. */@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);// 隐藏状态栏this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);// 把Activity的标题去掉requestWindowFeature(Window.FEATURE_NO_TITLE);// 设置布局this.setContentView(new MySurfaceView(this));} }
SurfaceView:
package com.view; import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.view.KeyEvent; import android.view.MotionEvent; import android.view.SurfaceHolder; import android.view.SurfaceHolder.Callback; import android.view.SurfaceView; public class MySurfaceView extends SurfaceView implements Runnable, Callback { private SurfaceHolder mHolder; // 用于控制SurfaceViewprivate Thread t; // 声明一条线程private boolean flag; // 线程运行的标识,用于控制线程private Canvas mCanvas; // 声明一张画布private Paint p; // 声明一支画笔private int x = 50, y = 50, r = 10; // 圆的坐标和半径public MySurfaceView(Context context) {super(context);mHolder = getHolder(); // 获得SurfaceHolder对象mHolder.addCallback(this); // 为SurfaceView添加状态监听p = new Paint(); // 创建一个画笔对象p.setColor(Color.WHITE); // 设置画笔的颜色为白色setFocusable(true); // 设置焦点}/*** 自定义一个方法,在画布上画一个圆*/public void Draw() {mCanvas = mHolder.lockCanvas(); // 获得画布对象,开始对画布画画mCanvas.drawRGB(0, 0, 0); // 把画布填充为黑色mCanvas.drawCircle(x, y, r, p); // 画一个圆mHolder.unlockCanvasAndPost(mCanvas); // 完成画画,把画布显示在屏幕上}/*** 当SurfaceView创建的时候,调用此函数*/@Overridepublic void surfaceCreated(SurfaceHolder holder) {t = new Thread(this); // 创建一个线程对象flag = true; // 把线程运行的标识设置成truet.start(); // 启动线程}/*** 当SurfaceView的视图发生改变的时候,调用此函数*/@Overridepublic void surfaceChanged(SurfaceHolder holder, int format, int width,int height) {}/*** 当SurfaceView销毁的时候,调用此函数*/@Overridepublic void surfaceDestroyed(SurfaceHolder holder) {flag = false; // 把线程运行的标识设置成false}/*** 当屏幕被触摸时调用*/@Overridepublic boolean onTouchEvent(MotionEvent event) {x = (int) event.getX(); // 获得屏幕被触摸时对应的X轴坐标y = (int) event.getY(); // 获得屏幕被触摸时对应的Y轴坐标return true;}/*** 当用户按键时调用*/@Overridepublic boolean onKeyDown(int keyCode, KeyEvent event) {if(keyCode == KeyEvent.KEYCODE_DPAD_UP){//当用户点击↑键时y--;//设置Y轴坐标减1}return super.onKeyDown(keyCode, event);}@Overridepublic void run() {while (flag) {Draw(); // 调用自定义画画方法try {Thread.sleep(50); // 让线程休息50毫秒} catch (InterruptedException e) {e.printStackTrace();}}} }
MySurfaceView首先继承SurfaceView,然后实现Runnable和Callback接口
重写了Runnable的run方法和Callback的surfaceCreated(SurfaceHolder holder),surfaceChanged(SurfaceHolder holder, int format, int width,int height),surfaceDestroyed(SurfaceHolder holder)方法,
还实现了onTouchEvent(MotionEvent event),onKeyDown(int keyCode, KeyEvent event)方法来,详细的在代码里已注释。
希望本文所述对大家Android程序设计有所帮助。