Question


I am quite new to Android and OpenGL ES. I have to create a GUI in OpenGL and I would like to use it as a Fragment in the main activity. In order to learn how to do this, I tried 2 tutorials - this Fragment tutorial and the Android developer tutorial on OpenGL ES.

But still I don't understand how exactly do I include an OpenGL view in a Fragment. OpenGL doesn't use XML layout files so this process is quite confusing for me. I would like to do something like this: inside the main activity from the Fragment tutorial I want to include a third Fragment with OpenGL. Go easy on me I am a beginner :)



up vote2down voteaccepted

If the developer tutorial is anything to go by, then the following setup would work:

Activity:

public class MainActivity extends FragmentActivity
{
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        getSupportFragmentManager().addOnBackStackChangedListener(new OnBackStackChangedListener()
        {
            public void onBackStackChanged()
            {
                int backCount = getSupportFragmentManager().getBackStackEntryCount();
                if (backCount == 0)
                {
                    finish();
                }
            }
        });

        if (savedInstanceState == null)
        {
            getSupportFragmentManager().beginTransaction().add(R.id.main_container, new OpenGLFragment()).addToBackStack(null).commit();
        }
    }
}

Activity XML (activity_main.xml):

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main_container"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

Fragment:

public class OpenGLFragment extends Fragment
{ 
    private GLSurfaceView mGLView;

    public OpenGLFragment()
    {
        super();
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
    {
        mGLView = new MyGLSurfaceView(this.getActivity()); //I believe you may also use getActivity().getApplicationContext();
        return mGLView;
    }
}

And I guess you need to make your own GLSurfaceView as the tutorial says:

class MyGLSurfaceView extends GLSurfaceView {

    public MyGLSurfaceView(Context context){
        super(context);
        setEGLContextClientVersion(2);    
        // Set the Renderer for drawing on the GLSurfaceView
        setRenderer(new MyRenderer());

    }
}

And as the tutorial says, make your renderer:

public class MyGLRenderer implements GLSurfaceView.Renderer {

    public void onSurfaceCreated(GL10 unused, EGLConfig config) {
        // Set the background frame color
        GLES20.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    }

    public void onDrawFrame(GL10 unused) {
        // Redraw background color
        GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
    }

    public void onSurfaceChanged(GL10 unused, int width, int height) {
        GLES20.glViewport(0, 0, width, height);
    }
}