Question

I am new to Android programming and Threads. I want to get a picture from a remote Server and display it. (that works so far ^^)
But the picture is from a camera and so I need a new one as soon as I show the one I downloaded before. That means ,that the Thread should never stop grabbing the picture. (As long the Activity exists.)
Also I just want to establish 1 connection to the server and then just do HTTP-gets. So I have to have an parameter “connection” that the Thread can use.

To get an idea – it should work something like this (but obviously it does not):

private class DownloadImageTask extends AsyncTask<URLConnection, Void, Bitmap> {
    /** The system calls this to perform work in a worker thread and
      * delivers it the parameters given to AsyncTask.execute() */
   private URLConnection connection = null;
    protected Bitmap doInBackground(URLConnection...connection ) {
        this.connection = connection[0];
        return getImageFromServer(connection[0]);
    }
    protected void onPostExecute(Bitmap result) {
        pic.setImageBitmap(result);
        this.doInBackground(connection);
    }
}

Answer 1

Might be better to use a Thread here since AsyncTask is for when the Task ends at some point. Something like below could work for you. Apart from that you could be better off using a local Service

protected volatile boolean keepRunning = true;
private Runnable r = new Runnable() {
    public void run() {
        // methods are a bit bogus but it should you give an idea.
        UrlConnection c = createNewUrlConnection();
        while (keepRunning) {
            Bitmap result = getImageFromServer(c);
            // that probably needs to be wrapped in runOnUiThread()
            pic.setImageBitmap(result);
        }
        c.close();
    }
};
private Thread t = null;

onResume() {
    keepRunning = true;
    t = new Thread(r);
    t.start();
}

onPause() {
    keepRunning = false;
    t = null;
}