Unable to update a view from within a new Thread

[ryank]

I create a new thread to update an ImageSwitcher but I get this message. "Only the original thread that created a view hierarchy can touch its view."

Do I need to send a message to the parent thread to update the imageswitcher? If so, do you have any code samles on how to do that?

Here is a piece of my code.

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Using java Syntax Highlighting

1.  
2. new Thread(r).start();
3.  
4. .....
5.  
6. ......
7.  
8. .....          
9.  
10. Runnable r = new Runnable() {
11.  
12. public void run() {
13.  
14.                         while (!done) {
15.  
16.                                 updateImage();
17.  
18.                         }
19.  
20.                 }
21.  
22.         };
23.  
24.        
25.  
26.         public void updateImage()
27.  
28.         {
29.  
30.                 try {
31.  
32.                         URL url = new URL(mImageURLIds[num]);
33.  
34.                         URLConnection conn = url.openConnection();
35.  
36.                         conn.setAllowUserInteraction(false);
37.  
38.                         conn.setConnectTimeout(1000);
39.  
40.                         conn.setReadTimeout(1000);
41.  
42.                         conn.connect();
43.  
44.                         InputStream is = conn.getInputStream();
45.  
46.                         BufferedInputStream bis = new BufferedInputStream(is);
47.  
48.                         Bitmap bm = BitmapFactory.decodeStream(bis);
49.  
50.                         bis.close();
51.  
52.                         is.close();
53.  
54.                         BitmapDrawable bmd = new BitmapDrawable(bm);
55.  
56.                         mSwitcher.setImageDrawable(bmd);
57.  
58.                 } catch (IOException e) {
59.  
60.                         Log.e("UpdateImage:::", e.getMessage(), e);
61.  
62.                 }              
63.  
64.         }

Parsed in 0.034 seconds, using GeSHi 1.0.8.4

Thanks for your help!

[plusminus]

Hello ryank,

Solution: Taken from the :src: PizzaTimer-Tutorial: (Important is that you get the idea behind ):

:idea: The "problem" is, that for security reasons, only the Thread that created the View is allowed to do sth. with it, like redrawing it with an invalidate();-call. So we need an Object 'in' the GUI-Thread that receives messages that mean like: "Hey 'Main-Thread' update your gui!". We will use a so called Handler for that.

• There will be a Thread, that sends a message that means "UPDATEYOURGUI" to the Handler.
• In the GUI-Thread, when the Handler receives the Message("UPDATEYOURGUI") it causes an invalidate(); to all participating Views.

If this is still not clear, feel free to ask your question