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See more: Mobile OpenGL Android
Hi there,

I'm now trying to mastering OpenGL for mobile gaming, so I'll need to ask a boxes of question about it. Here's my current problem now.

Specification :
- android SDK API 6 (android 2.1)
- using command line to create new project, build, and install
- using emulator (AVD) to run program
- Windows 7 Pro SP 1 32x

I'm trying to rotate triangle in my android on touch (onTouchEvent).
Here's my code snippet :

package .....;
import android.content.Context;
import android.opengl.GLSurfaceView;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;
public class segitiga extends Activity{
class HelloOpenGLES10SurfaceView extends GLSurfaceView {
public HelloOpenGLES10SurfaceView(Context context){
    public boolean onTouchEvent(MotionEvent e) {
        float x = e.getX();
        float y = e.getY();
        switch (e.getAction()) {
            case MotionEvent.ACTION_MOVE:
                float dx = x - mPreviousX;
                float dy = y - mPreviousY;
                // reverse direction of rotation above the mid-line
                if (y > getHeight() / 2) {
                  dx = dx * -1 ;
                // reverse direction of rotation to left of the mid-line
                if (x < getWidth() / 2) {
                  dy = dy * -1 ;
                mRenderer.mAngle += (dx + dy) * TOUCH_SCALE_FACTOR;
        mPreviousX = x;
        mPreviousY = y;
        return true;

The porblem is when I tried to compile (install debug / adb installd ) to my emulator it's throw me error like this on the line of :
public boolean onTouchEvent(MotionEvent e)

It need ";" after onTouchEvent and after "e". So it should be this like according to the compiler :
public boolean onTouchEvent;(MotionEvent e;)

And that's wrong things.
How should I fixe it?

Thanks in advances
Posted 25-Apr-12 18:08pm

1 solution

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Solution 1

It looks like you are nesting the functions. onTouchEvent() is placed within the function HelloOpenGLES10SurfaceView(). It needs to be placed in a class directly, either the main class, or a nested class.
satrio_budidharmawan 26-Apr-12 5:05am
But it's should be there I thought.
Because its GLSurfaceView's member, if I moved it out, it wont even know requestRender() and some things.
Niklas Lindquist 26-Apr-12 5:11am
In that case, place it outside of HelloOpenGLES10SurfaceView's constructor.
satrio_budidharmawan 26-Apr-12 5:14am
So its classless?
satrio_budidharmawan 26-Apr-12 5:16am
But somehow I tried to separate it onto 3 different files : main, view, and renderer.
And it works like charms, but I still wanted to know what's wrong with my previous version
Niklas Lindquist 26-Apr-12 5:34am
It's not "classless". It should look like:
class HelloOpenGLES10SurfaceView extends GLSurfaceView {
public HelloOpenGLES10SurfaceView(Context context){
} // end construtor
public boolean onTouchEvent(MotionEvent e) {
} // End class
satrio_budidharmawan 26-Apr-12 5:39am
mRenderer = new HelloOpenGLES10Renderer();
underneath public HelloOpenGLES10SurfaceView(Context context){...}
would be unknown I thought,

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