Prevent crashing if the user exits the AddComputerManually activity before the job completes

src/com/limelight/AddComputerManually.java

@@ -2,6 +2,7 @@ package com.limelight;
 
 import java.net.InetAddress;
 import java.net.UnknownHostException;
+import java.util.concurrent.LinkedBlockingQueue;
 
 import com.limelight.computers.ComputerManagerService;
 import com.limelight.utils.Dialog;
@@ -22,51 +23,86 @@ import android.widget.Toast;
 public class AddComputerManually extends Activity {
 	private Button addPcButton;
 	private TextView hostText;
+	private ComputerManagerService.ComputerManagerBinder managerBinder;
+	private LinkedBlockingQueue<String> computersToAdd = new LinkedBlockingQueue<String>();
+	private Thread addThread;
 	private ServiceConnection serviceConnection = new ServiceConnection() {
 		public void onServiceConnected(ComponentName className, final IBinder binder) {
-			new Thread() {
+			managerBinder = ((ComputerManagerService.ComputerManagerBinder)binder);
-				@Override
+			startAddThread();
-				public void run() {
-					String msg;
-					boolean finish = false;
-					try {
-						InetAddress addr = InetAddress.getByName(hostText.getText().toString());
-						
-						if (!((ComputerManagerService.ComputerManagerBinder)binder).addComputerBlocking(addr)){
-							msg = "Unable to connect to the specified computer. Make sure the required ports are allowed through the firewall.";
-						}
-						else {
-							msg = "Successfully added computer";
-							finish = true;
-						}
-					} catch (UnknownHostException e) {
-						msg = "Unable to resolve PC address. Make sure you didn't make a typo in the address.";
-					}
-					
-					final boolean toastFinish = finish;
-					final String toastMsg = msg;
-					AddComputerManually.this.runOnUiThread(new Runnable() {
-						@Override
-						public void run() {
-							// Unbind from this service
-							unbindService(AddComputerManually.this.serviceConnection);
-							
-							Toast.makeText(AddComputerManually.this, toastMsg, Toast.LENGTH_LONG).show();
-							
-							if (toastFinish) {
-								// Close the activity
-								AddComputerManually.this.finish();
-							}
-						}
-					});
-				}
-			}.start();
 		}
 
 		public void onServiceDisconnected(ComponentName className) {
+			joinAddThread();
+			managerBinder = null;
 		}
 	};
 	
+	private void doAddPc(String host) {
+		String msg;
+		boolean finish = false;
+		try {
+			InetAddress addr = InetAddress.getByName(host);
+			
+			if (!managerBinder.addComputerBlocking(addr)){
+				msg = "Unable to connect to the specified computer. Make sure the required ports are allowed through the firewall.";
+			}
+			else {
+				msg = "Successfully added computer";
+				finish = true;
+			}
+		} catch (UnknownHostException e) {
+			msg = "Unable to resolve PC address. Make sure you didn't make a typo in the address.";
+		}
+		
+		final boolean toastFinish = finish;
+		final String toastMsg = msg;
+		AddComputerManually.this.runOnUiThread(new Runnable() {
+			@Override
+			public void run() {
+				Toast.makeText(AddComputerManually.this, toastMsg, Toast.LENGTH_LONG).show();
+				
+				if (toastFinish && !isFinishing()) {
+					// Close the activity
+					AddComputerManually.this.finish();
+				}
+			}
+		});
+	}
+	
+	private void startAddThread() {
+		addThread = new Thread() {
+			@Override
+			public void run() {
+				while (!isInterrupted()) {
+					String computer;
+					
+					try {
+						computer = computersToAdd.take();
+					} catch (InterruptedException e) {
+						return;
+					}
+					
+					doAddPc(computer);
+				}
+			}
+		};
+		addThread.setName("UI - AddComputerManually");
+		addThread.start();
+	}
+	
+	private void joinAddThread() {
+		if (addThread != null) {
+			addThread.interrupt();
+			
+			try {
+				addThread.join();
+			} catch (InterruptedException e) {}
+			
+			addThread = null;
+		}
+	}
+
 	@Override
 	protected void onStop() {
 		super.onStop();
@@ -74,6 +110,16 @@ public class AddComputerManually extends Activity {
 		Dialog.closeDialogs();
 	}
 	
+	@Override
+	protected void onDestroy() {
+		super.onDestroy();
+		
+		if (managerBinder != null) {
+			joinAddThread();
+			unbindService(serviceConnection);
+		}
+	}
+	
 	@Override
 	protected void onCreate(Bundle savedInstanceState) {
 		super.onCreate(savedInstanceState);
@@ -82,6 +128,10 @@ public class AddComputerManually extends Activity {
 		
 		this.addPcButton = (Button) findViewById(R.id.addPc);
 		this.hostText = (TextView) findViewById(R.id.hostTextView);
+		
+		// Bind to the ComputerManager service
+		bindService(new Intent(AddComputerManually.this,
+				ComputerManagerService.class), serviceConnection, Service.BIND_AUTO_CREATE);
 	
 		addPcButton.setOnClickListener(new OnClickListener() {
 			@Override
@@ -92,9 +142,7 @@ public class AddComputerManually extends Activity {
 				}
 				
 				Toast.makeText(AddComputerManually.this, "Adding PC...", Toast.LENGTH_SHORT).show();
-				
+				computersToAdd.add(hostText.getText().toString());
-				// Bind to the service which will try to add the PC
-				bindService(new Intent(AddComputerManually.this, ComputerManagerService.class), serviceConnection, Service.BIND_AUTO_CREATE);
 			}
 		});
 	}