Simple GoogleMaps with Threads

[bsodmike]

Hi plusminus,

I've just been googling various examples for implementing threading on some apps and I've come across a few approaches.

1. http://codinghard.wordpress.com/2009/05 ... messaging/

Purely uses handlers and messaging; whilst debugging I can see that a child thread is created and it persists - it is also a singular thread similar to (3).

2. I tried to put together an example of threading as runnable, http://pastie.org/pastes/1400971

You will see some notes of the issues I ran into. In this example, I noticed that the thread would quit on completion. On each click of the button it'd load a new parallel thread - a pipeline thread isn't maintained.

3. http://mindtherobot.com/blog/159/androi ... -handlers/

This works as advertised, once I ported all the code into a SDK 2.2 project. However, I'm looking for something more elegant such as your solution here (am still testing this, or to be more specific, getting my head around it!).

Questions:

A. is there a particularly best practice type approach here?

B. messaging vs. runnable - thoughts?

C. http://pastie.org/pastes/1400971 << any thoughts on this?

D. I took your approach, yanked out the Geo stuff just to see how the threading works and it's similar in operation to *my* messy approach that I took with runnable in (C) above.

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Using java Syntax Highlighting

1.         public void onClick(View v) {
2.                              
3.                 Thread pipelineThread = new Thread() {
4.                         public void run(){
5.                                 final String TAG = "pipelineThread";
6.                                 try {
7.                                         Log.i(TAG, "before sleep");
8.                                         Thread.sleep(1500); //just to show you that it works
9.                                         Log.i(TAG, "after sleep");
10.                                 } catch (Exception e) {
11.                                         // @todo: Show error message
12.                                 }
13.                                 showResults.sendEmptyMessage(0);                                        
14.                         }
15.                 };
16.                 pipelineThread.start();
17.         }

Parsed in 0.032 seconds, using GeSHi 1.0.8.4

Thanks,
Mike

mike@bsodmike.com / @bsodmike on Twitter

[bsodmike]

Here's the source of my first attempt with your Geo approach, and the same implementing the activity as Runnable.

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Using java Syntax Highlighting

1. package com.threading;
2.  
3. import android.app.Activity;
4. import android.os.Bundle;
5. import android.os.Handler;
6. import android.os.Message;
7. import android.util.Log;
8. import android.view.View;
9. import android.view.View.OnClickListener;
10. import android.widget.Button;
11. import android.widget.ProgressBar;
12. import android.widget.TextView;
13.  
14. public class ThreadingActivity extends Activity implements OnClickListener, Runnable {
15.         Thread pipelineThread;
16.     /** Called when the activity is first created. */
17.     @Override
18.     public void onCreate(Bundle savedInstanceState) {
19.                 super.onCreate(savedInstanceState);
20.                 setContentView(R.layout.main);
21.                
22.                 TextView textOutput = (TextView)findViewById(R.id.textOutput);
23.                 Button buttonPush = (Button)findViewById(R.id.buttonPush); // Get button from xml
24.         ProgressBar progressBar = (ProgressBar) findViewById(R.id.progressBar);        
25.                
26.                 buttonPush.setOnClickListener(this);
27.         }
28.  
29.  
30.     public void onClick(View v) {
31.                          
32.         pipelineThread = new Thread(this) {
33.                 /*
34.                  * 1. uncomment this and "Runnable" from above
35.                  * 2. comment lines 68-80
36.                  */
37. //              public void run(){
38. //                      final String TAG = "pipelineThread";
39. //                      try {
40. //                              Log.i(TAG, "before sleep (" + this.getName() + ")");
41. //                              Thread.sleep(1500); //just to show you that it works
42. //                              Log.i(TAG, "after sleep (" + this.getName() + ")");
43. //                      } catch (Exception e) {
44. //                              // @todo: Show error message
45. //                      }
46. //                      showResults.sendEmptyMessage(0);                                        
47. //              }
48.             };
49.             pipelineThread.start();
50.     }
51.  
52.  
53.     private Handler showResults = new Handler() {
54.         public static final String TAG = "handler_showResults";
55.        
56.         @Override
57.         public void handleMessage(Message msg) {
58.                 Log.i(TAG, "received message: "+ (Object)msg.obj +  " (" + this.getLooper().getThread().getName() + ")");
59.        
60.                 super.handleMessage(msg);
61.         }
62.     };
63.  
64.  
65.     /*
66.      * ThreadingActivity implements Runnable
67.      */
68.     @Override
69.         public void run() {
70.                 // TODO Auto-generated method stub
71.         final String TAG = "pipelineThread";
72.         try {
73.                 Log.i(TAG, "before sleep (" + pipelineThread.getName() + ")");
74.                 Thread.sleep(1500); //just to show you that it works
75.                 Log.i(TAG, "after sleep (" + pipelineThread.getName() + ")");
76.         } catch (Exception e) {
77.             // @todo: Show error message
78.         }
79.     showResults.sendEmptyMessage(0);                   
80.         }
81.                
82. }
83.  
84.  

Parsed in 0.041 seconds, using GeSHi 1.0.8.4

The output of running this as Runnable is different; if I trigger a mass of clicks - only the last thread handles all the responding.

Code: Select all

I/ActivityManager(   66): Displayed activity com.threading/.ThreadingActivity: 5014 ms (total 5014 ms)
I/pipelineThread( 1308): before sleep (Thread-8)
I/pipelineThread( 1308): before sleep (Thread-9)
I/pipelineThread( 1308): before sleep (Thread-10)
I/pipelineThread( 1308): after sleep (Thread-10)
I/handler_showResults( 1308): received message: null (main)
I/pipelineThread( 1308): after sleep (Thread-10)
I/handler_showResults( 1308): received message: null (main)
I/pipelineThread( 1308): after sleep (Thread-10)
I/handler_showResults( 1308): received message: null (main)


Running as per plusminus's preferred way,

Code: Select all

I/ActivityManager(   66): Displayed activity com.threading/.ThreadingActivity: 1680 ms (total 1680 ms)
I/pipelineThread( 1339): before sleep (Thread-8)
I/pipelineThread( 1339): before sleep (Thread-9)
I/pipelineThread( 1339): before sleep (Thread-10)
I/pipelineThread( 1339): after sleep (Thread-8)
I/handler_showResults( 1339): received message: null (main)
I/pipelineThread( 1339): after sleep (Thread-9)
I/handler_showResults( 1339): received message: null (main)
I/pipelineThread( 1339): after sleep (Thread-10)
I/handler_showResults( 1339): received message: null (main)