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Android游戏开发使用View还是SurfaceView

在android中开发游戏,一般来说,或想写一个复杂一点的游戏,是必须用到SurfaceView来开发的。 经过这一阵子对android的学习,我找到了自已在android中游戏...


  在android中开发游戏,一般来说,或想写一个复杂一点的游戏,是必须用到SurfaceView来开发的。
经过这一阵子对android的学习,我找到了自已在android中游戏开发的误区,不要老想着用Layout和view去实现,不要将某个游戏中的对象做成一个组件来处理。应该尽量想着在Canvas(画布)中画出游戏戏中的背景、人物、动画等...
SurfaceView提供直接访问一个可画图的界面,可以控制在界面顶部的子视图层。SurfaceView是提供给需要直接画像素而不是使用窗体部件的应用使用的。Android图形系统中一个重要的概念和线索是surface。View及其子类(如TextView, Button)要画在surface上。每个surface创建一个Canvas对象(但属性时常改变),用来管理view在surface上的绘图操作,如画点画线。
还要注意的是,使用它的时候,一般都是出现在最顶层的:The view hierarchy will take care of correctly compositing with the Surface any siblings of the SurfaceView that would normally appear on top of it.

使用的SurfaceView的时候,一般情况下还要对其进行创建,销毁,改变时的情况进行监视,这就要用到SurfaceHolder.Callback.class BBatt extends SurfaceView implements SurfaceHolder.Callback {
public void surfaceChanged(SurfaceHolder holder,int format,int width,int height){}
//看其名知其义,在surface的大小发生改变时激发
public void surfaceCreated(SurfaceHolder holder){}
//同上,在创建时激发,一般在这里调用画图的线程。
public void surfaceDestroyed(SurfaceHolder holder) {}
//同上,销毁时激发,一般在这里将画图的线程停止、释放。
}


例子:

public class BBatt extends SurfaceView implements SurfaceHolder.Callback, OnKeyListener {
  private BFairy bFairy;
  private DrawThread drawThread;
  public BBatt(Context context) {
  super(context);
  this.setLayoutParams(new ViewGroup.LayoutParams(Global.battlefieldWidth,Global.battlefieldHeight));
  this.getHolder().addCallback( this );
  this.setFocusable( true );
  this.setOnKeyListener( this );
  bFairy = new BFairy(this.getContext());
  }
  public void surfaceChanged(SurfaceHolder holder, int format,int width,int height) {
  drawThread = new DrawThread(holder);
  drawThread.start();
  }
  public void surfaceDestroyed(SurfaceHolder holder) {
  if( drawThread != null ) {
  drawThread.doStop();
  while (true) try {
  drawThread.join();
  break ;
  } catch(Exception ex) {}
  }
  }
  public boolean onKey(View view, int keyCode, KeyEvent event) {}
}

实例2:用线程画一个蓝色的长方形。

package com.g3.test;
/*
* SurfaceView的示例程序
* 演示其流程
*/
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class Test extends Activity {
  public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(new MyView(this));
  }
   
  //内部类
  class MyView extends SurfaceView implements SurfaceHolder.Callback{

  SurfaceHolder holder;
public MyView(Context context) {
  super(context);
  holder = this.getHolder();//获取holder
  holder.addCallback(this);
  //setFocusable(true);
   
}

@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
   
}

@Override
public void surfaceCreated(SurfaceHolder holder) {
  new Thread(new MyThread()).start();
}

@Override
public void surfaceDestroyed(SurfaceHolder holder) {
   
}

//内部类的内部类
class MyThread implements Runnable{

  @Override
  public void run() {
  Canvas canvas = holder.lockCanvas(null);//获取画布
  Paint mPaint = new Paint();
  mPaint.setColor(Color.BLUE);
   
  canvas.drawRect(new RectF(40,60,80,80), mPaint);
  holder.unlockCanvasAndPost(canvas);//解锁画布,提交画好的图像
   
  }
   
}
   
  }
}

访问SurfaceView的底层图形是通过SurfaceHolder接口来实现的,通过getHolder()方法可以得到这个SurfaceHolder对象。你应该实现surfaceCreated(SurfaceHolder)和surfaceDestroyed(SurfaceHolder)方法来知道在这个Surface在窗口的显示和隐藏过程中是什么时候创建和销毁的。
SurfaceView可以在多线程中被访问。
注意:一个SurfaceView只在SurfaceHolder.Callback.surfaceCreated() 和 SurfaceHolder.Callback.surfaceDestroyed()调用之间是可用的,其他时间是得不到它的Canvas对象的(null)。

我的访问过程:
创建一个SurfaceView的子类,实现SurfaceHolder.Callback接口。
得到这个SurfaceView的SurfaceHolder对象holder。
holder.addCallback(callback),也就是实现SurfaceHolder.Callback接口的类对象。
在SurfaceHolder.Callback.surfaceCreated()调用过后holder.lockCanvas()对象就可以得到SurfaceView对象对应的Canvas对象canvas了。
用canvas对象画图。
画图结束后调用holder.unlockCanvasAndPost()就把图画在窗口中了。
SurfaceView可以多线程访问,在多线程中画图。


import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class MySurfaceView extends SurfaceView implements SurfaceHolder.Callback {


private Context mContext;
private SurfaceHolder mHolder;

public TouchScreenAdjusterSurfaceView(Context context,) {
super(context);

mContext = context;

mHolder = TouchScreenAdjusterSurfaceView.this.getHolder();
mHolder.addCallback(TouchScreenAdjusterSurfaceView.this);

this.setFocusableInTouchMode(true); // to make sure that we can get
// touch events and key events,and
// "setFocusable()" to make sure we
// can get key events
}

@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
// TODO Auto-generated method stub

}

@Override
public void surfaceCreated(SurfaceHolder holder) {
//now you can get the Canvas and draw something here
}

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

}


public void drawMyShape(PointPostion ps) {

mCanvas = mHolder.lockCanvas();

// draw anything you like

mHolder.unlockCanvasAndPost(mCanvas);
}

}

作者“恶人谷”