How to get the text from radio button in a radio group when radio button checked state is changed

xml file

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >

<RadioGroup
    android:id="@+id/radioSex"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" >

    <RadioButton
        android:id="@+id/radioMale"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/radio_male" 
        android:checked="true" />

    <RadioButton
        android:id="@+id/radioFemale"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/radio_female" />

</RadioGroup>

<Button
    android:id="@+id/btnDisplay"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/btn_display" />

</LinearLayout>

java code

package com.mkyong.android;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;

public class MyAndroidAppActivity extends Activity {
    private RadioGroup radioSexGroup;
    private RadioButton radioSexButton;
    private Button btnDisplay;

    @Override
    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    addListenerOnButton();

    }

    public void addListenerOnButton() {

        radioSexGroup = (RadioGroup) findViewById(R.id.radioSex);
        btnDisplay = (Button) findViewById(R.id.btnDisplay);

        btnDisplay.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {

                    // get selected radio button from radioGroup
                int selectedId = radioSexGroup.getCheckedRadioButtonId();

                // find the radiobutton by returned id
                    radioSexButton = (RadioButton) findViewById(selectedId);

                Toast.makeText(MyAndroidAppActivity.this,
                    radioSexButton.getText(), Toast.LENGTH_SHORT).show();

            }

        });

    }
}

try following code

radiogroup.setOnCheckedChangeListener(new OnCheckedChangeListener() {

        @Override
        public void onCheckedChanged(RadioGroup group, int checkedId) {
            int id=group.getCheckedRadioButtonId();
            RadioButton rb=(RadioButton) findViewById(id);
                                     OR
            RadioButton rb=(RadioButton) findViewById(checkedId);

            String radioText=rb.getText().toString();

        }
    });

try this...

    radioGroup.setOnCheckedChangeListener(new OnCheckedChangeListener() {

        @Override
        public void onCheckedChanged(RadioGroup group, int checkedId) {
            RadioButton radioButton = (RadioButton) group.findViewById(checkedId);
            String text = radioButton.getText().toString();
            updated_list.add(text);
        }
    });