Java – Chat application in android so that the sender and receiver messages should be on different sides

 protected void onPostExecute( ArrayList<HashMap<String,String>> myArrayList)//    for arraylist(ArrayList<String> result)
   {                            

for (HashMap<String, String> data : myArrayList)
      {
           String sender_no = data.get(TAG_SENDER_NO);
           String msg1=data.get(TAG_SEN_MSG);
           String receiver_no=data.get(TAG_RECEIVER_NO);

if(sender_no.equals(senderno))
           {

ListAdapter adapter = new SimpleAdapter(SinglechatActivity.this, myArrayList,R.layout.list_row_layout_even, 
           new String[] { TAG_SEN_MSG },new int[] { R.id.message_me });

  CustomList adapter= new CustomList(SinglechatActivity.this,myArrayList);//sender_no,  msg1,   receiver_no);

ListView  lv = (ListView) findViewById(R.id.listview);
           lv.setAdapter( adapter);

}

else

{
               ListAdapter adapter = new SimpleAdapter(SinglechatActivity.this, myArrayList,R.layout.list_row_layout_odd, 
                       new String[] { TAG_SEN_MSG },new int[] { R.id.message_frnd });

  CustomList adapter= new CustomList(SinglechatActivity.this,  sender_no,  msg1,   receiver_no);

ListView  lv = (ListView) findViewById(R.id.listview);
                   lv.setAdapter( adapter);

}

Here, I want to send messages on the right and left sides depending on the sender and receiver.

Use custom adapters for separate layouts for sender and receiver messages. It is called a heterogeneous ListView.

Like this

public class MyAdapter extends BaseAdapter {

ArrayList<HashMap<String,String>> messages;
    int SENDER_MESSAGE = 0;
    int RECEIVER_MESSAGE = 1;
    Context context;

@Override
    public int getCount() {
        return messages.size();
    }

@Override
    public Object getItem(int position) {
        return messages.get(position);
    }

@Override
    public long getItemId(int position) {
        return position;
    }

@Override
    public int getViewTypeCount() {
        return 2;
    }

@Override
    public int getItemViewType(int position) {

This is dummy logic
        Write your own logic to differentiate between sender and receiver message
        if (position % 2 == 0) {
            return SENDER_MESSAGE;
        }

else {
            return RECEIVER_MESSAGE;
        }
    }

@Override
    public View getView(int position, View convertView, ViewGroup parent) {

if (convertView == null) {
            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);

if (getItemViewType(position) == SENDER_MESSAGE) {
                convertView = inflater.inflate(R.layout.sender_message_layout, null);
            } 

else {
                Received message
                convertView = inflater.inflate(R.layout.received_message_layout, null);
            }
        }

//... set text to message layout here

}

}

For more information about custom adapters, you can refer to this

http://www.vogella.com/articles/AndroidListView/article.html#adapterown_example

The Heterogeneous ListView (Different row layouts in ListView) tutorial can refer to this

http://chrislee.kr/wp/tag/getitemviewtype-tutorial/