Android ViewGroup Rotation in 3d

Question

I want to rotate my own FrameLayout in 3d in android. Do i have to use GlSurfaceView class. I am new in computer graphics but know the theory behind the rotations and translations. In order to make 3d opengl rotations we do the followings generally.

In activity class we create a GLSurfaceView object and set its renderer. Renderer object is created from a class which implements GlSurfaceView.Renderer interface.

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    GLSurfaceView view = new GLSurfaceView(this);
    view.setRenderer(new OpenGLRenderer());
    setContentView(view);
}

In our Renderer class we make the drawings, rotations and translations with following methods

// Called when the surface is created or recreated.
public void onSurfaceCreated(GL10 gl, EGLConfig config) 

// Called to draw the current frame.
public void onDrawFrame(GL10 gl)

// Called when the surface changed size.
public void onSurfaceChanged(GL10 gl, int width, int height)

However i have a custom framelayout which is declared as

public class RotatedMapView extends FrameLayout

I want to make this :

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    RotatedMapView  view = new RotatedMapView (this);
    view.setRenderer(new OpenGLRenderer());
    setContentView(view);
}

But i can't, because setRenderer is special for GlSurfaceView. I am now browsing the GlSurfaceView.java source code in order to adapt it to my design. The link i found for GlSurfaceVİew.java is http://code.google.com/p/apps-for-android/source/browse/trunk/SpriteMethodTest/src/com/android/spritemethodtest/GLSurfaceView.java?r=150 The source is too long. In fact I am not lazy to read it but i want to be sure whether or not i am in correct way.

Answer 1

Framelayouts (and anything extending View) are designed to be drawn on a Canvas element in 2D. It is not possible to draw these using openGL. If you want to draw a GUI in 3D/GL then you will have to code that up from scratch or find a library which has already done this. I'm sure there are a few out there but I haven't had the need for one yet.

You can get some fake looking 3D effects on views by using scale animations, though these will only work if the animation is done fast so the user doesn't notice. This probably isn't what you are after.

<set xmlns:android="http://schemas.android.com/apk/res/android">
<scale
    android:fromXScale="1.0" android:toXScale="0.0"
    android:fromYScale="1.0" android:toYScale="1.0"
    android:pivotX="50%" android:pivotY="0%"
    android:duration="@android:integer/config_shortAnimTime"
/>

Answer 2

Now i am looking at animations which i have never used. In api demos there is a rotation example over y axis. I want to make rotation over x. It is succesful for negative angles but in positive direction it disappears the view. The function is below.

@Override
protected void applyTransformation(float interpolatedTime, Transformation t) {
    final float fromDegrees = mFromDegrees;
    float degrees = fromDegrees + ((mToDegrees - fromDegrees) * interpolatedTime);

    final float centerX = mCenterX;
    final float centerY = mCenterY;
    final Camera camera = mCamera;

    final Matrix matrix = t.getMatrix();

    camera.save();
    if (mReverse) {
        camera.translate(0.0f, 0.0f, mDepthZ * interpolatedTime);
    } else {
        camera.translate(0.0f, 0.0f, mDepthZ * (1.0f - interpolatedTime));
    }
    camera.rotateY(degrees);
    `camera.rotateX(degrees);  //i want to do this it works for negative but not` //positive angles 

camera.getMatrix(matrix);
camera.restore();

matrix.preTranslate(-centerX, -centerY);
matrix.postTranslate(centerX, centerY);

}