Update View at runtime in Android

Posted by seretur on Stack Overflow See other posts from Stack Overflow or by seretur
Published on 2010-12-21T20:12:36Z Indexed on 2010/12/22 20:53 UTC
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The example is pretty straightforward: i want to let the user know about what the app is doing by just showing a text (canvas.drawText()). Then, my first message appears, but not the other ones. I mean, i have a "setText" method but it doesn't updates.

onCreate(Bundle bundle) {
    super.onCreate(bundle);
    setContentView(splash); // splash is the view class
    loadResources();
    splash.setText("this");
    boundWebService();
    splash.setText("that"):
    etc();
    splash.setText("so on");
}

The view's text drawing works by doing just a drawText in onDraw();, so setText changes the text but doesn't show it.

Someone recommended me replacing the view with a SurfaceView, but it would be alot of trouble for just a couple of updates, SO... how the heck can i update the view dinamically at runtime?

It should be quite simple, just showing a text for say 2 seconds and then the main thread doing his stuff and then updating the text...

Thanks!

Update:

I tried implementing handler.onPost(), but is the same story all over again. Let me put you the code:

package coda.tvt;

import android.app.Activity; import android.graphics.Canvas; import android.graphics.Paint; import android.os.Bundle; import android.view.View; import android.widget.TextView; import android.widget.Toast;

public class ThreadViewTestActivity extends Activity {

Thread t;
Splash splash;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    splash = new Splash(this);
    t = new Thread(splash);
    t.start();

    splash.setTextow("OA");
    try { Thread.sleep(4000); } catch (InterruptedException e) { }
    splash.setTextow("LALA");
}       
}

And:

public class Splash implements Runnable {

Activity activity;
final Handler myHandler = new Handler();

public Splash(Activity activity) {
    this.activity=activity;
}   

@Override
public void run() {
    // TODO Auto-generated method stub

}

public synchronized void setTextow(final String textow) {
    // Wrap DownloadTask into another Runnable to track the statistics
    myHandler.post(new Runnable() {
        @Override
        public void run() {
            TextView t = (TextView)activity.findViewById(R.id.testo);
            t.setText(textow);
            t.invalidate(); 
        }                   
    });
}
}

Although splash is in other thread, i put a sleep on the main thread, i use the handler to manage UI and everything, it doesn't changes a thing, it only shows the last update.

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