Problem with ProgressDialog

nico · by **nico** » Sun Jan 13, 2008 1:36 pm

Actually it's not the problem with ProgressDialog, but it's my problem for not being able to use it :lol:

Here's my code:

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package com.nico.ProgressDialogTest;
 
import java.util.ArrayList;
 
import java.util.List;
 
import android.app.ListActivity;
 
import android.app.ProgressDialog;
 
import android.os.Bundle;
 
import android.view.View;
 
import android.widget.ArrayAdapter;
 
import android.widget.ListView;
 
public class ProgressDialogTest extends ListActivity {
 
        ProgressDialog myProgressDialog = null;
 
        private List<String> directoryEntries = new ArrayList<String>();
 
        private ProgressDialog p;
 
        @Override
 
        public void onCreate(Bundle icicle) {
 
                super.onCreate(icicle);
 
                directoryEntries.add("Click me");
 
                directoryEntries.add("Click me too");
 
                ArrayAdapter<String> directoryList = new ArrayAdapter<String>(
 
                                ProgressDialogTest.this, R.layout.file_row,
 
                                directoryEntries);
 
                setListAdapter(directoryList);
 
        }
 
        private void createList() {
 
                // TODO Auto-generated method stub
 
                p = ProgressDialog.show(ProgressDialogTest.this, "Please wait..", "Loading list..", true);
 
                new Thread(){
 
                        public void run(){
 
                                //do some extreme work before creating list
 
                                try {
 
                                        sleep(5000);
 
                                } catch (InterruptedException e) {
 
                                        // TODO Auto-generated catch block
 
                                        e.printStackTrace();
 
                                }
 
                                directoryEntries.clear();
 
                                directoryEntries.add("Android");
 
                                directoryEntries.add("Developer");
 
                                directoryEntries.add("Challenge");
 
                                p.dismiss();
 
                        }
 
                }.start();
 
                ArrayAdapter<String> directoryList = new ArrayAdapter<String>(
 
                                ProgressDialogTest.this, R.layout.file_row,
 
                                directoryEntries);
 
                setListAdapter(directoryList);
 
        }
 
        protected void onListItemClick(ListView l, View v, int position, long id) {
 
                createList();
 
        }
 
}
Parsed in 0.038 seconds,  using GeSHi 1.0.8.4

what i want to do is to do something heavy before updating the list, thus i use the ProgressDialog while the work is in progress. But using above code, the list is not updated. I believe the problem is because the method setListAdapter(directoryList) is called before the content of the list updated. The problem is i don't know how to solve this problem :oops:

Please help, everyone :wink:

plusminus · by **plusminus** » Sun Jan 13, 2008 2:00 pm

Hello nico,

yes, you are 100% right. Your program splits to another thread and things get indeterministic (by chance it could work as you posted it

)
Moving the following lines to the end of the run()-method of the new Thread should do what you want to.

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          ArrayAdapter<String> directoryList = new ArrayAdapter<String>(
                    ProgressDialogTest.this, R.layout.file_row,
                    directoryEntries);
          setListAdapter(directoryList); 
Parsed in 0.033 seconds,  using GeSHi 1.0.8.4

Perhaps you have to place a "ProgressDialogTest.this." before setListAdapter(...);

Tell us if it solve your problem

.

Regards,
plusminus

nico · by **nico** » Sun Jan 13, 2008 2:33 pm

hi plusminus,

i did that before but it returned error.

i was thinking of using thread synchronizing, but didn't work, i never good with that synchronized stuff

any idea?

plusminus · by **plusminus** » Sun Jan 13, 2008 3:08 pm

Hello nico,

aaawww of course

forgot that point.

:idea:

Solution: Taken from the :src: PizzaTimer-Tutorial: (will be really doable to adopt for your problem. 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 :!:

kaobiore · by **kaobiore** » Sun Jan 13, 2008 3:13 pm

Hi!

I had exactly the same problem but I guess I've found a solution for it here :wink:

So, just send a "message" out of the created thead (process-dialog) to the (let's call it) main-thread (through a handler).

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    protected static final int GUIUPDATEIDENTIFIER = 0x101; 
 
    Handler myViewUpdateHandler = new Handler(){
        // @Override
        public void handleMessage(Message msg) {
             switch (msg.what) {
                  case MainClass.GUIUPDATEIDENTIFIER:
                       // Do some GUI Stuff here
                       break;
             }
             super.handleMessage(msg);
        }
   };    
 
    private void somethingToWaitFor() {
       this.myProgressDialog = ProgressDialog.show(MainClass.this,
                "Please wait", "...", true);
       
       new Thread() {
            public void run() {
                try {
                                        Thread.sleep(1500);
                                } catch (InterruptedException e) {
                                        // nothing
                                }
                                // Close Progress-Dialog
                MainClass.this.myProgressDialog.dismiss();
                
                // Send message to main-thread - update gui
                Message m = new Message();
                m.what = MainClass.GUIUPDATEIDENTIFIER;
                MainClass.this.myViewUpdateHandler.sendMessage(m); 
            }
       }.start();
    }
 
Parsed in 0.039 seconds,  using GeSHi 1.0.8.4

I don't know if there might be a better solution but it works fine for me

Cheers
-kao-

plusminus · by **plusminus** » Sun Jan 13, 2008 3:20 pm

two answers at the same time, I was a bit faster

But thanks for your response @kaobiore.

Regards,
plusminus

nico · by **nico** » Sun Jan 13, 2008 5:35 pm

plusminus wrote::lol: two answers at the same time, I was a bit faster

But thanks for your response @kaobiore.

Regards,
plusminus

i should be the one who thanks you both, it works! and i understand now, thankyou very much :wink:

i really love this forum

Problem with ProgressDialog

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