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January 30, 2013

 

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Android : Method onPictureTaken never called, even with AsyncTask

 

I want to
With the activity “GameActivity”
Take a picture
Save the picture on SD card
Use the picture with another activity

The problem is, when I just save the picture and do nothing with it, the picture is saved. When I start the activity (method startActivity) just after camera.takePicture, the method onPictureTaken is never called.

I’ve read it was because the method takePicture is long to execute so I’ve followed the advice on this site (http://www.workreloaded.com/2011/06/how-to-use-the-android-camera/) and created a class that extends AsyncTask

public class PhotoTask extends AsyncTask<Boolean, Void, Void> {
public PhotoTask(Camera camera, SurfaceView surfaceCamera,boolean isPreview, SurfaceHolder holder, GameActivity gameactivity) {
constructor
}

    @Override
protected Void doInBackground(Boolean... params) {
     camera.takePicture(null,null, myPictureCallback_JPG);
        Log.w("GAMEACTIVITY","TAKEPICTURE");
        return null;
}

    @Override
protected void onPostExecute(Void result) {
    Log.w("GAMEACTIVITY","INTENT");
     Intent intent = new Intent(gameactivity.getApplicationContext(),ShareActivity.class);
     // Sending the picture taken to ShareActivity
     intent.putExtra("PICTURE_TAKEN", output);
     gameactivity.startActivity(intent);
}

PictureCallback myPictureCallback_JPG = new PictureCallback(){

    @Override
    public void onPictureTaken(byte[] data, Camera camera) {
        Log.w("GAMEACTIVITY","FIRST");
            File imagesFolder = new File(Environment.getExternalStorageDirectory(), "/KersplattFolder");
            imagesFolder.mkdirs();
            SimpleDateFormat dateFormat = new SimpleDateFormat("yyyymmddhhmmss");
            String date = dateFormat.format(new Date());
            String fileName = "Kersplatt_" + date + ".jpg";
            output = new File(imagesFolder, fileName);
            try {
                FileOutputStream fos = new FileOutputStream(output);
                fos.write(data);
                fos.close();
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }
            catch (IOException e) {
                e.printStackTrace();
            }
            camera.startPreview();
            }
};

}

While in GameActivity I have

PhotoTask photoTask = new PhotoTask(camera,surfaceCamera,isPreview,holder,GameActivity.this);
photoTask.execute(null);

when the screen is touched (to take a photo)

Why does my method onPictureTaken is not called there? (yet called when I delete onPostExecute method)

 

Answer

i would recommend taking

 Intent intent = new Intent(gameactivity.getApplicationContext(),ShareActivity.class);
 // Sending the picture taken to ShareActivity
 intent.putExtra("PICTURE_TAKEN", output);
 gameactivity.startActivity(intent);

to PictureCallback instead of onPostExecute

when you are done with storing image then move to next activity