Alert messagebox toast Android example code

public class MainActivity extends Activity implements OnClickListener {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        LinearLayout layout = (LinearLayout) findViewById(R.id.layout);
            RadioGroup radioGroup = new RadioGroup(this);
            
            LinearLayout.LayoutParams p = new LinearLayout.LayoutParams(
                    LinearLayout.LayoutParams.FILL_PARENT,
                    LinearLayout.LayoutParams.WRAP_CONTENT
            );
            layout.addView(radioGroup, p);

            RadioButton radioButtonView = new RadioButton(this);
            radioButtonView.setText("RadioButton");
            radioButtonView.setOnClickListener(this);
            radioGroup.addView(radioButtonView, p);
            
            RadioButton radioButtonView2 = new RadioButton(this);
            radioButtonView2.setText("RadioButton2");
            radioButtonView2.setOnClickListener(mThisButtonListener);
            radioGroup.addView(radioButtonView2, p);
        
    }
    
    public void onClick(View view) {
    	 try {
    	  String s = ((RadioButton) view).getText().toString();
    	  Toast.makeText(MainActivity.this, "This is: " + s,
    			  Toast.LENGTH_LONG).show();
    	 }
    	 catch (Exception e1) {
    	   e1.printStackTrace();
    	 }
    	}
    
    private OnClickListener mThisButtonListener = new OnClickListener() {
        public void onClick(View v) {
        	String s = ((RadioButton) v).getText().toString();
        	Toast.makeText(MainActivity.this, "Hello from 2!" + s,
        			Toast.LENGTH_LONG).show();
        }
    };

}

   <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:focusable="true" 
        android:focusableInTouchMode="true"
        android:orientation="vertical" >
</LinearLayout>