Android MjpegDemo修改

Question

I am trying to understand Android MjpegDemo code that I found. This code streams IP camera video to android app. In the original app Mjpeg view takes up an entire screen and doesn't use an activity.xml in the layout dir (which is what I am used to seeing). This is partial code for the MjpegSample.java which loads as main activity. I think I understand that setContentView(mv) and WindowManager.LayoutParams.FLAG_FULLSCREEN is the reason everything fills the screen. Is there a way to work with this type of an Activity and still add other objects, like buttons or backgrounds?

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);     
}

}

Answer 1

Here is a detailed example on how to achieve this. Here, we use a LinearLayout object as the main view content, then we add our View objects to this (I also included an example LinearLayout that is nested inside the main one, to show how you can embed View containers within other View containers):

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));


    }
}