Android - ViewRootImpl$CalledFromWrongThreadException

Solution 1:

I got the same problem trying to change UI view from c++ using JNI. The solution was use

runOnUiThread(new Runnable() {
    public void run(){   
    }
});

runOnUiThread is an Activity method so I have to make my activity instance public static to be able to call on my public static method who later call from JNI.

Hope this help others :)

PS: from here I learn how to use JNI http://www.cocos2d-x.org/projects/cocos2d-x/wiki/How_to_use_jni for my android game previously made with cocos2dx

Solution 2:

Put this in onCreate()

ImageView imageView;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.order);
        imageView = (ImageView)findViewById(R.id.imgView);
        new DownloadFilesTask().execute();       
    } 

And your AsyncTask class should be like this,

        private class DownloadFilesTask extends AsyncTask<Void, Void, Void> {
             Drawable drawable;

             @Override
             protected Void doInBackground(Void... params) {
             drawable = createDrawableFromURL(
                                   "http://savagelook.com/misc/sl_drop2.png");
              return null;
             }
             protected void onPostExecute(Void result) {
                    imageView.setImageDrawable(drawable);
            }          
        } 

Solution 3:

I think this line is causing the error..

  imageView.setImageDrawable(createDrawableFromURL("http://savagelook.com/misc/sl_drop2.png"));

and the error explains why it is so..

     Only the original thread that created a view hierarchy can touch its views.

this error is caused because you are trying to change the User Interface on mainthread from some other thread.. here doInBackground in your case...