Myujth

I'm practicing multi-client networking using a Java Server and Android clients. I have done this with Java clients before so I adapted my solution mostly around what I know in Java using multithreading. Which is extending a thread for each client connection created. I usually have a separate ClientConnection class in Java but here I used a protected inner class.

This solution works but someone mentioned to me that I might want to do this with AsyncTask rather. What benefits would using AsyncTask offer rather than extending a thread the way I have done here?

Please note I am not asking for any code or how I would go about doing it. Just what benefits it would offer over this method.

Client Layout

<RelativeLayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:paddingLeft="@dimen/activity_horizontal_margin"
 android:paddingRight="@dimen/activity_horizontal_margin"
 android:paddingTop="@dimen/activity_vertical_margin"
 android:paddingBottom="@dimen/activity_vertical_margin"
 tools:context="za.ac.nmu.wrap302.jan2015.MainActivity">

<LinearLayout
 android:orientation="vertical"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:id="@+id/loginPanel"
 android:layout_alignParentBottom="true">
 <EditText
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:id="@+id/etHandle"
 android:layout_alignParentTop="true"
 android:layout_alignParentLeft="true"
 android:layout_alignParentStart="true"
 android:layout_alignParentRight="true"
 android:layout_alignParentEnd="true"/>
 <Button
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:text="Connect"
 android:id="@+id/btnConnect"
 android:layout_below="@+id/etHandle"
 android:layout_alignParentLeft="true"
 android:layout_alignParentStart="true"
 android:layout_alignRight="@+id/etHandle"
 android:layout_alignEnd="@+id/etHandle"/>
</LinearLayout>
<LinearLayout
 android:orientation="vertical"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:id="@+id/chatPanel"
 android:visibility="gone">
 <ListView
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:id="@+id/lvMessages"
 android:layout_below="@+id/btnConnect"
 android:layout_alignParentLeft="true"
 android:layout_alignParentStart="true"
 android:layout_above="@+id/txtMessage"/>
 <Button
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:text="Change Room"
 android:id="@+id/btnRoom"/>
 <EditText
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:id="@+id/txtMessage"
 android:layout_above="@+id/btnDisconnect"
 android:layout_alignParentLeft="true"
 android:layout_alignParentStart="true"
 android:layout_alignRight="@+id/btnDisconnect"
 android:layout_alignEnd="@+id/btnDisconnect"/>
</LinearLayout>
<LinearLayout
 android:background="?android:colorBackground"
 android:orientation="vertical"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:id="@+id/roomPanel"
 android:visibility="gone">
 <Button
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:text="Disconnect"
 android:id="@+id/btnDisconnect"
 android:layout_alignParentBottom="true"
 android:layout_alignParentLeft="true"
 android:layout_alignParentStart="true"
 android:layout_alignRight="@+id/lvMessages"
 android:layout_alignEnd="@+id/lvMessages"/>
 <ListView
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:id="@+id/lvRooms"/>
</LinearLayout>

Client Code

public class MainActivity extends AppCompatActivity 
EditText etHandle;
ConnectionThread connectionThread;
private ArrayList<String> messages;
private ArrayAdapter<String> adapter;

private ArrayList<String> rooms;
private ArrayAdapter<String> roomsAdapter;

private static final String SET_HANDLE = "#SetHandle";
private static final String SEND_MESSAGE = "#SendMessage";
private static final String DISCONNECT = "#Disconnect";
private static final String JOIN_ROOM = "#JoinRoom";
private static final String LIST_ROOMS = "#ListRooms";

ListView lvMessages;
ListView lvRooms;

EditText textMessage;
Button btnConnect;
Button btnDisconnect;
Button btnRoom;
LinearLayout chatPanel, roomPanel, loginPanel;

@Override
protected void onCreate(Bundle savedInstanceState) 
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);

 etHandle = (EditText) findViewById(R.id.etHandle);
 lvMessages = (ListView) findViewById(R.id.lvMessages);
 textMessage = (EditText) findViewById(R.id.txtMessage);
 btnConnect = (Button) findViewById(R.id.btnConnect);
 btnDisconnect = (Button) findViewById(R.id.btnDisconnect);
 chatPanel = (LinearLayout) findViewById(R.id.chatPanel);
 roomPanel = (LinearLayout) findViewById(R.id.roomPanel);
 loginPanel = (LinearLayout) findViewById(R.id.loginPanel);
 lvRooms = (ListView) findViewById(R.id.lvRooms);
 btnRoom = (Button) findViewById(R.id.btnRoom);

 messages = new ArrayList<String>();
 adapter = new ArrayAdapter<String>(this,
 android.R.layout.simple_selectable_list_item, messages);
 lvMessages.setAdapter(adapter);

 rooms = new ArrayList<String>();
 roomsAdapter = new ArrayAdapter<String>(this,
 android.R.layout.simple_selectable_list_item, rooms);
 lvRooms.setAdapter(roomsAdapter);

 btnConnect.setOnClickListener(new View.OnClickListener() 
 @Override
 public void onClick(View view) 
 connectionThread = new ConnectionThread(etHandle.getText().toString());
 connectionThread.start();
 
 );

 btnDisconnect.setOnClickListener(new View.OnClickListener() 
 @Override
 public void onClick(View view) 
 Thread out = new Thread(new Runnable() 
 @Override
 public void run() 
 try 
 connectionThread.out.writeUTF(DISCONNECT);
 catch (IOException e) 
 e.printStackTrace();
 
 
 );
 out.start();
 hideRoomScreen();
 showLoginScreen();
 
 );

 btnRoom.setOnClickListener(new View.OnClickListener() 
 @Override
 public void onClick(View view) 
 showRoomScreen();
 Thread out = new Thread(new Runnable() 
 @Override
 public void run() 
 try 
 connectionThread.out.writeUTF(LIST_ROOMS);
 catch (IOException e) 
 e.printStackTrace();
 
 
 );
 out.start();
 
 );

 textMessage.setOnKeyListener(new View.OnKeyListener() 
 @Override
 public boolean onKey(View v, int keyCode, KeyEvent event) 
 if ((keyCode == KeyEvent.KEYCODE_ENTER) && (event.getAction() == KeyEvent.ACTION_DOWN)) 
 final String text = textMessage.getText().toString();
 Thread out = new Thread(new Runnable() 
 @Override
 public void run() 
 try 
 connectionThread.out.writeUTF(SEND_MESSAGE);
 connectionThread.out.writeUTF(text);
 catch (IOException e) 
 e.printStackTrace();
 
 
 );
 out.start();
 textMessage.getText().clear();
 return true;
 
 return false;
 
 );

 lvRooms.setOnItemClickListener(new AdapterView.OnItemClickListener() 
 @Override
 public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) 
 final String roomName = roomsAdapter.getItem(i);
 Thread out = new Thread(new Runnable() 
 @Override
 public void run() 
 try 
 connectionThread.out.writeUTF(JOIN_ROOM);
 connectionThread.out.writeUTF(roomName);
 catch (IOException e) 
 e.printStackTrace();
 
 
 );
 out.start();
 hideRoomScreen();
 showChatScreen();
 
 );


public void addMessage(String message) 
 adapter.add(message);
 lvMessages.setSelection(adapter.getCount() - 1);


public void addRoom(final String roomName)
 runOnUiThread(new Runnable() 
 @Override
 public void run() 
 roomsAdapter.add(roomName);
 
 );


protected class ConnectionThread extends Thread 
 Socket connection;
 DataInputStream in;
 DataOutputStream out;
 String handle;
 boolean connected;

 public ConnectionThread(String name) 
 handle = name;
 

 @Override
 public void run() 
 try 
 connection = new Socket("10.0.0.10", 1234);
 connected = true;

 in = new DataInputStream(connection.getInputStream());
 out = new DataOutputStream(connection.getOutputStream());

 out.writeUTF(handle);

 hideLoginScreen();
 btnRoom.callOnClick();

 String command = "";
 while (connected) 
 command = in.readUTF();
 switch (command) 
 case SEND_MESSAGE:
 final String user = in.readUTF();
 final String message = in.readUTF();
 runOnUiThread(new Runnable() 
 @Override
 public void run() 
 addMessage(user + ": " + message);
 
 );
 break;
 case DISCONNECT:
 showLoginScreen();
 connected = false;
 break;
 case LIST_ROOMS:
 int count = in.readInt();
 runOnUiThread(new Runnable() 
 @Override
 public void run() 
 roomsAdapter.clear();
 
 );
 for(int i = 0; i < count; i++)
 String roomName = in.readUTF();
 addRoom(roomName);
 
 break;
 
 

 catch (IOException e) 
 e.printStackTrace();
 

 


private void showLoginScreen() 
 runOnUiThread(new Runnable() 
 @Override
 public void run() 
 loginPanel.setVisibility(View.VISIBLE);
 
 );


private void hideLoginScreen() 
 runOnUiThread(new Runnable() 
 @Override
 public void run() 
 loginPanel.setVisibility(View.GONE);
 
 );


private void showChatScreen() 
 runOnUiThread(new Runnable() 
 @Override
 public void run() 
 chatPanel.setVisibility(View.VISIBLE);
 
 );


private void hideChatScreen() 
 runOnUiThread(new Runnable() 
 @Override
 public void run() 
 chatPanel.setVisibility(View.GONE);
 
 );


private void showRoomScreen() 
 runOnUiThread(new Runnable() 
 @Override
 public void run() 
 roomPanel.setVisibility(View.VISIBLE);
 
 );


private void hideRoomScreen() 
 runOnUiThread(new Runnable() 
 @Override
 public void run() 
 roomPanel.setVisibility(View.GONE);
 
 );

AsyncTask was not designed to remain active and to receive commands, so I'm not agree with who suggest to use it.
You need a Thread that remains active for an undetermined amount of time and that receive commands. It's physically possible to use AsyncTask in that similar way but this case is similar to one that uses a Component for a complete different thing, like when using a TextView to display images (by substitute common ImageView and manually draw on TextView): it's possible but....the question is: "WHY?"

There isn't any advantage by using it.