Android : how to select inbox msg display on another activity of textview

I am new android developer.I selected msg from inbox display on textview of another activity. Three java file mainactivity.java-select msg display on TextView 7

    Intent intent = getIntent();
        String msg = intent.getStringExtra("Msg_Detail");
        //String msg = intent.getExtras().getString("Msg_Detail");
        TextView7 = (TextView) findViewById(R.id.TextView7);
        TextView7.setText(msg);
**MessageBox.java**
lvMsg = (ListView) findViewById(R.id.lvMsg);
        Uri inboxURI = Uri.parse("content://sms/inbox");

        // List required columns
        String[] reqCols = new String[] { "_id", "address", "body" };

        // Get Content Resolver object, which will deal with Content
        // Provider
        ContentResolver cr = getContentResolver();

        // Fetch Inbox SMS Message from Built-in Content Provider
        Cursor c = cr.query(inboxURI, reqCols, null, null, null);

        // Attached Cursor with adapter and display in listview
        adapter = new SimpleCursorAdapter(this, R.layout.row, c,
                new String[] { "body", "address" }, new int[] {
                        R.id.lblMsg, R.id.lblNumber });
        lvMsg.setAdapter(adapter);
        lvMsg.setOnItemClickListener(new OnItemClickListener() {

                    private Intent intent;

                    @Override
                    public void onItemClick(AdapterView<?> parent, View view,
                       int position, long id) {
                   String msg=(String) lvMsg.getSelectedItem();
                        //String msg =(String)(lvMsg.getItemAtPosition(position));
                 //   String msg=((TextView)view.findViewById(R.id.lvMsg)).getText().toString();
                        //list item = (list) adapter.getItem(position);

                        Intent in = new Intent(getApplicationContext(),MainActivity.class);

                                        //String msg = null;
                                        in.putExtra("Msg_Detail", msg); 
                                        startActivity(in);

                 }
             }); 

list.java-(contain two textview(lblno,lblMsg)Inbox message display thar format ) setContentView(R.layout.row);

    txt = (TextView) findViewById(R.id.lblMsg);
    txt2= (TextView) findViewById(R.id.lblNumber);

I try comment coding also but when I select inbox msg the page go to Messagebox.java to mainactivity but not display msg. please check my Messagebox coding