Error: The content of the adapter has changed but ListView did not receive a notification

Hi All I have the following code:

enter code here

public class XMPPClient extends Activity {

private ArrayList<String> messages = new ArrayList<String>();
private Handler mHandler = new Handler();
private EditText mRecipient;
private EditText mSendText;
private ListView mList;
private XMPPConnection connection;
// private Chat chat;
private MultiUserChat muc;
private String to;

/**
 * Called with the activity is first created.
 */
@Override
public void onCreate(Bundle icicle) {
    super.onCreate(icicle);
    Log.i("XMPPClient", "onCreate called");
    setContentView(R.layout.chatroom);

    mSendText = (EditText) this.findViewById(R.id.sendText);
    Log.i("XMPPClient", "mSendText = " + mSendText);
    mList = (ListView) this.findViewById(R.id.listMessages);
    Log.i("XMPPClient", "mList = " + mList);
    setListAdapter();

    setConnection();


    // Set a listener to send a chat text message
    Button send = (Button) this.findViewById(R.id.send);
    send.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view) {
            // to = mRecipient.getText().toString();
            to = "nus@nus.rohit-pc";
            final String text = mSendText.getText().toString();

            Log.i("XMPPClient", "Sending text [" + text + "] to [" + to
                    + "]");
            Message msg = new Message(to, Message.Type.groupchat);
            msg.setBody(OptionsActivity.uname + ":" + text);

            try {
                muc.sendMessage(msg);
                // chat.sendMessage(text);
            } catch (XMPPException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            setListAdapter();

        }
    });
    OptionsActivity.pd.dismiss();
}

 public boolean onKeyDown(int keyCode, KeyEvent event)  {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            this.connection.disconnect();
            finish();
        }
        return false;

        }
/**
 * Called by Settings dialog when a connection is establised with the XMPP
 * server
 * 
 * @param connection
 */
public void setConnection() {
    this.connection = ChatApis.setupConnection();
    if (connection != null) {
        connection.getChatManager();
        muc = new MultiUserChat(connection, "nus@nus.rohit-pc");
        try {
            muc.join(connection.getUser());
        } catch (XMPPException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        muc.addMessageListener(new PacketListener() {

            @Override
            public void processPacket(Packet arg0) {
                // TODO Auto-generated method s开发者_如何学Pythontub
                // messages.add(fromName + ":");
                Message msg1 = (Message) arg0;
                messages.add(msg1.getBody());
                // Add the incoming message to the list view
                mHandler.post(new Runnable() {
                    public void run() {
                        // if(flag){
                        setListAdapter();
                        // }

                    }
                });


                Toast.makeText(XMPPClient.this, arg0.toString(),
                        Toast.LENGTH_SHORT).show();
                Log.i("XMPPClient", "text aaya [" + arg0.toString()
                        + "] to [" + arg0.toString() + "]");
            }
        });

    }
}

private void setListAdapter() {

    ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
            R.layout.multi_line_list_item, messages);
    adapter.notifyDataSetChanged();
    mList.setAdapter(adapter);
}

}

enter code here

can anyone point out the error? The content of the adapter has changed but ListView did not receive a notification. Make sure the content of your adapter is not modified from a background thread, but only from the UI thread.

I am really confused.

Thank rohit bhatnagar for the solution. I've resolved similarly case. After setAdapter() for listview, we should invoke notifyDataSetChanged() of adapter.

solved by changing following statement :

  ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
        R.layout.multi_line_list_item, messages);

to

  ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
        R.layout.multi_line_list_item);
        adapter.add(message);