Decoupling UI and Network threads

We pass the communication through a BlockingQueue now.

Author: ddalex

android/SnFChat/src/ro/ddalex/snfchat/MainActivity.java

@@ -1,6 +1,8 @@
 package ro.ddalex.snfchat;
 
 import java.util.ArrayList;
+import java.util.Timer;
+import java.util.TimerTask;
 
 import android.os.Bundle;
 import android.app.Activity;
@@ -19,14 +21,40 @@ public class MainActivity extends Activity {
 
 	private NetTalkerService service;
 
+	//private  MainActivity getMAThis() { return this; }
+	
 	@Override
 	protected void onCreate(Bundle savedInstanceState) {
 		super.onCreate(savedInstanceState);
 		setContentView(R.layout.activity_main);
 
 		Intent i = new Intent(this, NetTalkerService.class);
 		startService(i);
+	
+		// get a timer to get the service and then pull updates
+		final Timer t = new Timer();
+		t.schedule(
+		new TimerTask() {
+			@Override
+			public void run() {
+				while ((service = NetTalkerService.getInstance()) == null)
+				{
+					try {
+						Thread.sleep(10);
+					} catch (InterruptedException e) {
+					}
+				}
 
+				while (! service.getMessageQueue().isEmpty() )
+				{
+					String s = service.getMessageQueue().poll();
+					if (s != null)
+						displayNetMessage(s);
+				}
+			}
+		}, 10, 10);
+		
+		
 		ListView listView =  (ListView)findViewById(R.id.list);
 	    adapter=new ArrayAdapter<String>(this,
 	               android.R.layout.simple_list_item_1,
@@ -37,6 +65,7 @@ protected void onCreate(Bundle savedInstanceState) {
 	@Override
 	protected void onPause()
 	{
+		super.onPause();		
 		Intent i = new Intent(this, NetTalkerService.class);
 		stopService(i);		
 	}
@@ -55,17 +84,9 @@ public void displayNetMessage(String message)
 	}
 
 	public void sendNetMessage(View view)
-	{
-		
-		// busy wait here
-		while ((service = NetTalkerService.getInstance()) == null)
-		{
-			try {
-				Thread.sleep(10);
-			} catch (InterruptedException e) {
-			}
-		}
-		service.setActivity(this);
+	{		
+		if (service == null)
+			return;
 
 		EditText mEdit = (EditText) findViewById(R.id.editText1);
 		String text = mEdit.getText().toString();

android/SnFChat/src/ro/ddalex/snfchat/NetTalkerService.java

@@ -1,5 +1,9 @@
 package ro.ddalex.snfchat;
 
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.LinkedBlockingQueue;
+
 import android.app.Service;
 import android.content.Intent;
 import android.os.IBinder;
@@ -10,22 +14,45 @@ public class NetTalkerService extends Service {
 	private static NetTalkerService sInstance = null;
 	private String TAG = getClass().getSimpleName();
 
+	private BlockingQueue<String> incomingMessageQueue = new LinkedBlockingQueue<String>();
+	
+	public BlockingQueue<String> getMessageQueue() { return incomingMessageQueue;} 
+	
 	private class NetListener extends Thread {
 
+		private int c = 0;
+		
+		@Override
+		public void run()
+		{
+			while(true) {
+				incomingMessageQueue.offer("tata " + c);
+				try {
+					sleep(1000);
+				} catch (InterruptedException e) {
+					// TODO Auto-generated catch block
+					e.printStackTrace();
+				}
+				c++;
+			}
+		}
 	}
 
 	static public NetTalkerService getInstance(){
 		return sInstance;
 	}
 
-	private NetListener nl;
+	private NetListener nl = null;
 
     @Override
     public void onCreate() {
     	super.onCreate();
     	sInstance = this;
-    	
-    	nl.start();
+    	if (nl == null)
+    	{
+    		nl = new NetListener();
+    		nl.start();
+    	}
     	Log.i(TAG, "Service created");
     }
 
@@ -35,19 +62,10 @@ public IBinder onBind(Intent arg0) {
 		return null;
 	}
 
-	// Specific code here
-	private MainActivity mA = null;
-	public void setActivity(MainActivity a)
-	{
-		mA = a;
-	}
-	
 	public void postMessage(String s)
 	{
-		if (mA == null)
-			Log.e(TAG, "mA not available");
 		Log.i(TAG, "Posting " + s);
-		mA.displayNetMessage(s);
+		incomingMessageQueue.offer(s);
 	}
 
 	class NetReceiver{