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程序员文章站 2022-03-02 09:40:42

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转自：http://blog.csdn.net/andyhuabing/article/details/7657069 调试Media播放时，不时用到SurfaceView与SurfaceHolder对象，写case测试及实际运行效果，
基本上搞清楚这两个对象的用法及区别

1、SurfaceView
public class SurfaceView extends View
SurfaceView是视图(View)的继承类，这个视图里内嵌了一个专门用于绘制的Surface。你可以控制这个Surface的格式和尺寸。Surfaceview控制这个Surface的绘制位置。

surface是纵深排序(Z-ordered)的，这表明它总在自己所在窗口的后面。surfaceview提供了一个可见区域，只有在这个可见区域内的surface部分内容才可见，可见区域外的部分不可见。surface的排版显示受到视图层级关系的影响，它的兄弟视图结点会在顶端显示。这意味者 surface的内容会被它的兄弟视图遮挡，这一特性可以用来放置遮盖物(overlays)(例如，文本和按钮等控件)。注意，如果surface上面有透明控件，那么它的每次变化都会引起框架重新计算它和顶层控件的透明效果，这会影响性能。你可以通过SurfaceHolder接口访问这个Surface.用getHolder()方法可以得到这个接口。
surfaceview变得可见时，surface被创建；surfaceview隐藏前，surface被销毁。这样能节省资源。
如果你要查看 surface被创建和销毁的时机，可以重载surfaceCreated(SurfaceHolder)和 surfaceDestroyed(SurfaceHolder)。

surfaceview的核心在于提供了两个线程：UI线程和渲染线程。

这里应注意：

1> 所有SurfaceView和SurfaceHolder.Callback的方法都应该在UI线程里调用，一般来说就是应用程序主线程。
渲染线程所要访问的各种变量应该作同步处理。
2> 由于surface可能被销毁，它只在SurfaceHolder.Callback.surfaceCreated()和 SurfaceHolder.Callback.surfaceDestroyed()之间有效，所以要确保渲染线程访问的是合法有效的surface。

可以在主线程之外的线程中向屏幕绘图，这样可以避免画图任务繁重的时候造成主线程阻塞，从而提高了程序的反应速度。
在游戏开发中多用到SurfaceView，游戏中的背景、人物、动画等等尽量在画布canvas中画出。

2、SurfaceHolder
public interface SurfaceHolder

显示一个surface的抽象接口，使你可以控制surface的大小和格式，以及在surface上编辑像素，和监视surace的改变。

这个接口通常通过SurfaceView类实现。

surface的控制器，用来操纵surface，处理它的Canvas上画的效果和动画，控制表面，大小，像素等。
几个需要注意的方法：
(1)、abstract void addCallback(SurfaceHolder.Callback callback);
   // 给SurfaceView当前的持有者一个回调对象。
(2)、abstract Canvas lockCanvas();
   // 锁定画布，一般在锁定后就可以通过其返回的画布对象Canvas，在其上面画图等操作了。
(3)、abstract Canvas lockCanvas(Rect dirty);
   // 锁定画布的某个区域进行画图等..因为画完图后，会调用下面的unlockCanvasAndPost来改变显示内容。
   // 相对部分内存要求比较高的游戏来说，可以不用重画dirty外的其它区域的像素，可以提高速度。
(4)、abstract void unlockCanvasAndPost(Canvas canvas);
   // 结束锁定画图，并提交改变。

3、SurfaceHolder.Callback
用户可以实现此接口接收surface变化的消息。当用在一个SurfaceView 中时，它只在SurfaceHolder.Callback.surfaceCreated()和SurfaceHolder.Callback.surfaceDestroyed()之间有效。设置Callback的方法是SurfaceHolder.addCallback.
实现上一般继承SurfaceView并实现SurfaceHolder.Callback接口

下面我们举个例子说明一下这几个对象的用法：

[java] view plain copy print?

<span style=“font-size:16px;”>package com.test.surfaceview;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class TestsurfaceviewActivity extends Activity {
private final static String TAG = “TestsurfaceviewActivity”;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.main);
setContentView(new MySurfaceView(this)); // 这里以MySurfaceView作为显示View
}
class MySurfaceView extends SurfaceView implements SurfaceHolder.Callback{
private SurfaceHolder holder;
private MyThread mThread ;
public MySurfaceView(Context context){
super(context);
holder = this.getHolder(); //获取holder对象
holder.addCallback(this); // 添加surface回调函数
mThread = new MyThread(holder); //创建一个绘图线程
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO Auto-generated method stub
Log.i(TAG,”surfaceChanged is called”);
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
// TODO Auto-generated method stub
Log.i(TAG,”surfaceCreated is called”);
mThread.isRun = true;
mThread.start();
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
Log.i(TAG,”surfaceDestroyed is called”);
mThread.isRun = false;
mThread.stop();
}
}
class MyThread extends Thread{
private SurfaceHolder holder ;
public boolean isRun = false;
public MyThread(SurfaceHolder holder){
this.holder = holder;
isRun = true;
Log.i(TAG,”MyThread set surface holder”);
}
@Override
public void run(){
Canvas canvas = null;
int count = 0;
while (isRun) {
try {
synchronized (holder) {
canvas = holder.lockCanvas();// 锁定画布，一般在锁定后就可以通过其返回的画布对象Canvas，在其上面画图等操作了。
canvas.drawColor(Color.BLACK);// 设置画布背景颜色
Paint p = new Paint(); // 创建画笔
p.setColor(Color.RED);
Rect r = new Rect(500, 200, 300, 250);
canvas.drawRect(r, p);
canvas.drawText(”这是第” + (count++) + “秒”, 300, 310, p);
Thread.sleep(1000);// 睡眠时间为1秒
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (canvas != null) {
holder.unlockCanvasAndPost(canvas);// 结束锁定画图，并提交改变。
}
}
}
}
}
}</span>

package com.test.surfaceview;

import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class TestsurfaceviewActivity extends Activity {
    private final static String TAG = "TestsurfaceviewActivity";

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.main);
        setContentView(new MySurfaceView(this)); // 这里以MySurfaceView作为显示View
    }

    class MySurfaceView extends SurfaceView implements SurfaceHolder.Callback{
        private SurfaceHolder holder;
        private MyThread mThread ;

        public MySurfaceView(Context context){
            super(context);
            holder = this.getHolder(); //获取holder对象
            holder.addCallback(this); // 添加surface回调函数
            mThread = new MyThread(holder); //创建一个绘图线程
        }

        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int width,
                int height) {
            // TODO Auto-generated method stub
            Log.i(TAG,"surfaceChanged is called");
        }

        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            // TODO Auto-generated method stub
            Log.i(TAG,"surfaceCreated is called");

            mThread.isRun = true;
            mThread.start();
        }

        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            // TODO Auto-generated method stub
            Log.i(TAG,"surfaceDestroyed is called");

            mThread.isRun = false;
            mThread.stop();
        }
    }

    class MyThread extends Thread{
        private SurfaceHolder holder ;
        public  boolean isRun = false;

        public MyThread(SurfaceHolder holder){
            this.holder = holder;
            isRun = true;
            Log.i(TAG,"MyThread set surface holder");
        }

        @Override
        public void run(){
            Canvas canvas = null;
            int count = 0;
            while (isRun) {
                try {
                    synchronized (holder) {
                        canvas = holder.lockCanvas();// 锁定画布，一般在锁定后就可以通过其返回的画布对象Canvas，在其上面画图等操作了。
                        canvas.drawColor(Color.BLACK);// 设置画布背景颜色
                        Paint p = new Paint(); // 创建画笔
                        p.setColor(Color.RED);
                        Rect r = new Rect(500, 200, 300, 250);
                        canvas.drawRect(r, p);
                        canvas.drawText("这是第" + (count++) + "秒", 300, 310, p);
                        Thread.sleep(1000);// 睡眠时间为1秒
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    if (canvas != null) {
                        holder.unlockCanvasAndPost(canvas);// 结束锁定画图，并提交改变。
                    }
                }
            }
        }
    }
}

在Media 播放过程中会需要用到两个SurfaceView,一个用于绘制显示界面，另外一个用于播放视频的显示

首先在main.xml中定义两个SurfaceView:

然后使用的片断代码如下：

[java] view plain copy print?

private SurfaceView mUIView;
private SurfaceView mPlayView;
private MyMediaplayerManager mPlayManager;
mUIView = (SurfaceView)findViewById(R.id.mainSurface);
mSurfaceHolder.addCallback(new SurfaceHolder.Callback() {
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
@Override
public void surfaceCreated(final SurfaceHolder holder) {
// TODO Auto-generated method stub
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format,
int width, int height) {
// TODO Auto-generated method stub
}
});
mPlayView = (SurfaceView)findViewById(R.id.playSurface);
holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
holder.addCallback(new SurfaceHolder.Callback() {
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
mPlayManager.setDisplay(holder); // 这里设置video视频的显示Holder
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO Auto-generated method stub
}
});
// 设定SurfaceView的显示zorder序
mUIView.setZOrderMediaOverlay(true);
mPlayView.setZOrderMediaOverlay(false);

    private SurfaceView   mUIView;
    private SurfaceView   mPlayView;

    private MyMediaplayerManager mPlayManager;

    mUIView = (SurfaceView)findViewById(R.id.mainSurface);
    mSurfaceHolder.addCallback(new SurfaceHolder.Callback() {       
        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            // TODO Auto-generated method stub              
        }

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

    mPlayView = (SurfaceView)findViewById(R.id.playSurface);
    holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    holder.addCallback(new SurfaceHolder.Callback() {
        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            // TODO Auto-generated method stub
        }
        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            mPlayManager.setDisplay(holder); // 这里设置video视频的显示Holder
        }

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

    // 设定SurfaceView的显示zorder序
    mUIView.setZOrderMediaOverlay(true);
    mPlayView.setZOrderMediaOverlay(false);

view 可看作就是一个图层，以上使用两个图层，一个是图形层，另一个是视频层，需要播放视频时只需要将图形层透明掉即可。

surfaceview的核心在于提供了两个线程：UI线程和渲染线程。

这里应注意：

显示一个surface的抽象接口，使你可以控制surface的大小和格式，以及在surface上编辑像素，和监视surace的改变。

这个接口通常通过SurfaceView类实现。

下面我们举个例子说明一下这几个对象的用法：

[java] view plain copy print?

<span style=“font-size:16px;”>package com.test.surfaceview;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class TestsurfaceviewActivity extends Activity {
private final static String TAG = “TestsurfaceviewActivity”;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.main);
setContentView(new MySurfaceView(this)); // 这里以MySurfaceView作为显示View
}
class MySurfaceView extends SurfaceView implements SurfaceHolder.Callback{
private SurfaceHolder holder;
private MyThread mThread ;
public MySurfaceView(Context context){
super(context);
holder = this.getHolder(); //获取holder对象
holder.addCallback(this); // 添加surface回调函数
mThread = new MyThread(holder); //创建一个绘图线程
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO Auto-generated method stub
Log.i(TAG,”surfaceChanged is called”);
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
// TODO Auto-generated method stub
Log.i(TAG,”surfaceCreated is called”);
mThread.isRun = true;
mThread.start();
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
Log.i(TAG,”surfaceDestroyed is called”);
mThread.isRun = false;
mThread.stop();
}
}
class MyThread extends Thread{
private SurfaceHolder holder ;
public boolean isRun = false;
public MyThread(SurfaceHolder holder){
this.holder = holder;
isRun = true;
Log.i(TAG,”MyThread set surface holder”);
}
@Override
public void run(){
Canvas canvas = null;
int count = 0;
while (isRun) {
try {
synchronized (holder) {
canvas = holder.lockCanvas();// 锁定画布，一般在锁定后就可以通过其返回的画布对象Canvas，在其上面画图等操作了。
canvas.drawColor(Color.BLACK);// 设置画布背景颜色
Paint p = new Paint(); // 创建画笔
p.setColor(Color.RED);
Rect r = new Rect(500, 200, 300, 250);
canvas.drawRect(r, p);
canvas.drawText(”这是第” + (count++) + “秒”, 300, 310, p);
Thread.sleep(1000);// 睡眠时间为1秒
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (canvas != null) {
holder.unlockCanvasAndPost(canvas);// 结束锁定画图，并提交改变。
}
}
}
}
}
}</span>

package com.test.surfaceview;

import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class TestsurfaceviewActivity extends Activity {
    private final static String TAG = "TestsurfaceviewActivity";

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.main);
        setContentView(new MySurfaceView(this)); // 这里以MySurfaceView作为显示View
    }

    class MySurfaceView extends SurfaceView implements SurfaceHolder.Callback{
        private SurfaceHolder holder;
        private MyThread mThread ;

        public MySurfaceView(Context context){
            super(context);
            holder = this.getHolder(); //获取holder对象
            holder.addCallback(this); // 添加surface回调函数
            mThread = new MyThread(holder); //创建一个绘图线程
        }

        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int width,
                int height) {
            // TODO Auto-generated method stub
            Log.i(TAG,"surfaceChanged is called");
        }

        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            // TODO Auto-generated method stub
            Log.i(TAG,"surfaceCreated is called");

            mThread.isRun = true;
            mThread.start();
        }

        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            // TODO Auto-generated method stub
            Log.i(TAG,"surfaceDestroyed is called");

            mThread.isRun = false;
            mThread.stop();
        }
    }

    class MyThread extends Thread{
        private SurfaceHolder holder ;
        public  boolean isRun = false;

        public MyThread(SurfaceHolder holder){
            this.holder = holder;
            isRun = true;
            Log.i(TAG,"MyThread set surface holder");
        }

        @Override
        public void run(){
            Canvas canvas = null;
            int count = 0;
            while (isRun) {
                try {
                    synchronized (holder) {
                        canvas = holder.lockCanvas();// 锁定画布，一般在锁定后就可以通过其返回的画布对象Canvas，在其上面画图等操作了。
                        canvas.drawColor(Color.BLACK);// 设置画布背景颜色
                        Paint p = new Paint(); // 创建画笔
                        p.setColor(Color.RED);
                        Rect r = new Rect(500, 200, 300, 250);
                        canvas.drawRect(r, p);
                        canvas.drawText("这是第" + (count++) + "秒", 300, 310, p);
                        Thread.sleep(1000);// 睡眠时间为1秒
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    if (canvas != null) {
                        holder.unlockCanvasAndPost(canvas);// 结束锁定画图，并提交改变。
                    }
                }
            }
        }
    }
}

在Media 播放过程中会需要用到两个SurfaceView,一个用于绘制显示界面，另外一个用于播放视频的显示

首先在main.xml中定义两个SurfaceView:

然后使用的片断代码如下：

[java] view plain copy print?

private SurfaceView mUIView;
private SurfaceView mPlayView;
private MyMediaplayerManager mPlayManager;
mUIView = (SurfaceView)findViewById(R.id.mainSurface);
mSurfaceHolder.addCallback(new SurfaceHolder.Callback() {
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
@Override
public void surfaceCreated(final SurfaceHolder holder) {
// TODO Auto-generated method stub
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format,
int width, int height) {
// TODO Auto-generated method stub
}
});
mPlayView = (SurfaceView)findViewById(R.id.playSurface);
holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
holder.addCallback(new SurfaceHolder.Callback() {
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
mPlayManager.setDisplay(holder); // 这里设置video视频的显示Holder
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO Auto-generated method stub
}
});
// 设定SurfaceView的显示zorder序
mUIView.setZOrderMediaOverlay(true);
mPlayView.setZOrderMediaOverlay(false);

    private SurfaceView   mUIView;
    private SurfaceView   mPlayView;

    private MyMediaplayerManager mPlayManager;

    mUIView = (SurfaceView)findViewById(R.id.mainSurface);
    mSurfaceHolder.addCallback(new SurfaceHolder.Callback() {       
        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            // TODO Auto-generated method stub              
        }

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

    mPlayView = (SurfaceView)findViewById(R.id.playSurface);
    holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    holder.addCallback(new SurfaceHolder.Callback() {
        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            // TODO Auto-generated method stub
        }
        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            mPlayManager.setDisplay(holder); // 这里设置video视频的显示Holder
        }

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

    // 设定SurfaceView的显示zorder序
    mUIView.setZOrderMediaOverlay(true);
    mPlayView.setZOrderMediaOverlay(false);

view 可看作就是一个图层，以上使用两个图层，一个是图形层，另一个是视频层，需要播放视频时只需要将图形层透明掉即可。

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