Java Android MJPEG演示修改

我试图理解我找到的Android演示代码。此代码将IP摄像头视频流传输到android应用程序。在最初的应用程序中，Mjpeg视图占据了整个屏幕，在布局目录中没有使用activity.xml（这是我习惯看到的）。这是作为主活动加载的MjpegSample.java的部分代码。我想我知道setContentView（mv）和WindowManager.LayoutParams.FLAG_全屏显示是所有内容占据屏幕的原因。有没有一种方法可以在处理这种类型的活动时仍然添加其他对象，如按钮或背景

public class MjpegSample extends Activity {
private MjpegView mv;

public void onCreate(Bundle myBundle) {          
    super.onCreate(myBundle);

    String URL = "http://someURL/mjpg/video.mjpg"; 

    requestWindowFeature(Window.FEATURE_NO_TITLE);          
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, 
                         WindowManager.LayoutParams.FLAG_FULLSCREEN);

    mv = new MjpegView(this);
    setContentView(mv);  

    mv.setSource(MjpegInputStream.read(URL));
    mv.setDisplayMode(MjpegView.SIZE_BEST_FIT);     
}

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}下面是一个详细的示例，说明如何实现这一点。在这里，我们使用LinearLayout对象作为主视图内容，然后将视图对象添加到其中（我还包括嵌套在主视图中的LinearLayout示例，以展示如何将视图容器嵌入其他视图容器中）：

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这很有效。因此，看起来您可以通过编程方式添加对象并对视图进行分层。此方法根本不涉及“接口生成器”xml。谢谢你的解释。非常有用。

public class MjpegSample extends Activity {
    private MjpegView mv;

    private LinearLayout ll1;
    private LinearLayout nestedL;
    private Button btn1;
    private TextView txt1;

    public void onCreate(Bundle myBundle) {          
        super.onCreate(myBundle);

        //allow legacy-style network queries on UI thread (in case you compile for Android 3.0+, which do not allow
        //network transactions in main UI thread by default)
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy); 

        final String URL = "http://someURL/mjpg/video.mjpg"; 

        requestWindowFeature(Window.FEATURE_NO_TITLE);          
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, 
                             WindowManager.LayoutParams.FLAG_FULLSCREEN);

        //Create new button programmatically
        btn1 = new Button(this);
        btn1.setText("Test button 1");
        //set so that content is wrapped in its parent container (which will be the nestedL object below)
        btn1.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));

        //Create new TextView programmatically
        txt1 = new TextView(this);
        txt1.setText("Test text 1");
        //set so that content is wrapped in its parent container (which will be the nestedL object below)
        txt1.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));

        //Create new MjpegView programmatically
        mv = new MjpegView(this);
        //set so that content is wrapped in its parent container (which will be the ll1 object below)
        mv.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));

        nestedL = new LinearLayout(this);
        nestedL.setOrientation(LinearLayout.HORIZONTAL);
        //set so that content is wrapped in its parent container (which will be the ll1 object below)
        nestedL.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));

        //we add btn1 and txt1 in nestedL LinearLayout (they will be ordered horizontally, according to nestedL orientation
        //as configured above, and all those widgets will not be stretched either)
        nestedL.addView(btn1);
        nestedL.addView(txt1);

        //create the main LinearLayout widget which will be set as the view content using setContentView(...)
        ll1 = new LinearLayout(this);
        ll1.setOrientation(LinearLayout.VERTICAL);
        //we add the other LinearLayout (horizontal one) on top
        ll1.addView(nestedL);
        //then we add the video player thing
        ll1.addView(mv);

        //ll1 is set as the main view for your activity
        setContentView(ll1);  


        mv.setDisplayMode(MjpegView.SIZE_BEST_FIT);
        mv.setSource(MjpegInputStream.read(URL));


    }
}