Question

Here is a pseudo code :

class MoWeFi extends Activity


    static TouchSurfaceView TSV;
    static DrawRenderer mRenderer;
    static UserInterface mUI;
    DownloadData mDD = new DownloadData();
    static float zoom = 1.f;

    mDD.execute();
    mUI = new UserInterface();
    setContentView(mUI);

class UserInterface extends LinearLayout

    MoWeFi.TSV = new TouchSurfaceView(context);

    MoWeFi.mRenderer = new DrawRenderer(context);

    MoWeFi.TSV.setRenderer(MoWeFi.mRenderer);

    MoWeFi.TSV.setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY);

    this.addView(MoWeFi.TSV);
    TextView tv = new TextView(context);
    this.addView(tv);

    TextView tv2 = new TextView(context);
    this.addView(tv2);

class DownloadData extends AsyncTask

    protected Void doInBackground(){

        do{

        this.publishProgress();

        try{Thread.sleep(1000);catch (InterruptedException e){}

        }while(running)

    }

    @Override

    protected void onProgressUpdate(){

    //...

    MoWeFi.TSV.requestRender();

    MoWeFi.mUI.tv.setText("zoom="+MoWeFi.zoom); // IT DOES NOT WORK !!! ALWAYS GET 1.f.

    }
class TouchSurfaceView extends GLSurfaceView

    gl.glTranslatef(0, 0, -1.f / MoWeFi.zoom); // IT WORKS !!!
class DrawRenderer implements GLSurfaceView.Renderer

    //Pinch-zoom

    ...

    MoWeFi.zoom *= detector.getScaleFactor();

        MoWeFi.zoom = Math.max(0.5f, Math.min(MoWeFi.zoom, 5.0f));
MoWeFi.mUI.tv2.setText("zoom="+MoWeFi.zoom); // IT WORKS !!!


So no error whatsoever. Just not able to access my zoom variable everywhere.

I am new to Java, I am surely missing important concept.
EDIT add float in the first lines
EDIT 2 add publishProgress in the asyncTask
EDIT 3 logcat shows nothing
												

Answer 1

Are you sure your AsyncTask accesses the property after the value was changed? If yes, AsyncTask runs code on a separate thread so probably you’re facing a race condition where the value updated in one thread is not yet available in another. Try to make the zoom property volatile:

 public static volatile float zoom = 1.f;

or use synchronized get/set methods to mutate and access the property.