SharedPreferences.Editor for RadioButton in RadioGroup

Last post demonstrate how to "Read index of the checked RadioButton in RadioGroup" and explain why you cannot save in SharedPreferences.Editor base on IDs. This exercise demonstrate how to save the checked index of RadioButton in RadioGroup using SharedPreferences.Editor.

package com.example.androidradiogroup;

import android.os.Bundle;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.RadioGroup.OnCheckedChangeListener;
import android.widget.TextView;
import android.app.Activity;
import android.content.SharedPreferences;

public class MainActivity extends Activity {
 
 RadioGroup radioGroup;
 TextView textCheckedID, textCheckedIndex;
 
 final String KEY_SAVED_RADIO_BUTTON_INDEX = "SAVED_RADIO_BUTTON_INDEX";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        radioGroup = (RadioGroup)findViewById(R.id.radiogroup);
        radioGroup.setOnCheckedChangeListener(radioGroupOnCheckedChangeListener);
        
        textCheckedID = (TextView)findViewById(R.id.checkedid);
        textCheckedIndex = (TextView)findViewById(R.id.checkedindex);
        
        LoadPreferences();
    }
    
    OnCheckedChangeListener radioGroupOnCheckedChangeListener =
      new OnCheckedChangeListener(){

    @Override
    public void onCheckedChanged(RadioGroup group, int checkedId) {

     RadioButton checkedRadioButton = (RadioButton)radioGroup.findViewById(checkedId);
     int checkedIndex = radioGroup.indexOfChild(checkedRadioButton);
     
     textCheckedID.setText("checkedID = " + checkedId);
     textCheckedIndex.setText("checkedIndex = " + checkedIndex);
     SavePreferences(KEY_SAVED_RADIO_BUTTON_INDEX, checkedIndex);
    }};

 private void SavePreferences(String key, int value){
  SharedPreferences sharedPreferences = getSharedPreferences("MY_SHARED_PREF", MODE_PRIVATE);
  SharedPreferences.Editor editor = sharedPreferences.edit();
  editor.putInt(key, value);
  editor.commit(); 
 }
 
 private void LoadPreferences(){
  SharedPreferences sharedPreferences = getSharedPreferences("MY_SHARED_PREF", MODE_PRIVATE);
  int savedRadioIndex = sharedPreferences.getInt(KEY_SAVED_RADIO_BUTTON_INDEX, 0);
  RadioButton savedCheckedRadioButton = (RadioButton)radioGroup.getChildAt(savedRadioIndex);
  savedCheckedRadioButton.setChecked(true);
 }
}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <RadioGroup
        android:id="@+id/radiogroup"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">
        <RadioButton
            android:id="@+id/option1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Option 1" />
        <RadioButton
            android:id="@+id/option2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Option 2" />
        <RadioButton
            android:id="@+id/option3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Option 3" />
    </RadioGroup>
    
    <TextView
        android:id="@+id/checkedid"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
    <TextView
        android:id="@+id/checkedindex"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>

Related:
- Example of using SharedPreferences.Editor; getPreferences() for a single activity.
- Use getSharedPreferences() to retrieve a preferences object shared across multiple activity.