For Beginner

<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"
    android:gravity="center"
    tools:context=".MainActivity" >
    
    <TextView android:id="@+id/text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        />

    <RatingBar
        android:id="@+id/rating"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>
    
</LinearLayout>

public class MainActivity extends Activity implements OnRatingBarChangeListener{

private RatingBar ratingBar;
private TextView textView;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

ratingBar = (RatingBar)findViewById(R.id.rating);
textView = (TextView)findViewById(R.id.text);

ratingBar.setNumStars(5);
ratingBar.setStepSize(1);
ratingBar.setRating(3);

textView.setText("Rating: " + ratingBar.getProgress());
ratingBar.setOnRatingBarChangeListener(this);
}

@Override
public void onRatingChanged(RatingBar rb, float rating, boolean fromUser){
textView.setText("Rating: " + ratingBar.getProgress());
}

package com.kircode.codeforfood_test;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.widget.RatingBar;
import android.widget.RatingBar.OnRatingBarChangeListener;
import android.widget.TextView;

public class MainActivity extends Activity implements OnRatingBarChangeListener{

private RatingBar ratingBar;
private TextView textView;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

ratingBar = (RatingBar)findViewById(R.id.rating);
textView = (TextView)findViewById(R.id.text);

ratingBar.setNumStars(5);
ratingBar.setStepSize(1);
ratingBar.setRating(3);

textView.setText("Rating: " + ratingBar.getProgress());
ratingBar.setOnRatingBarChangeListener(this);
}

@Override
public void onRatingChanged(RatingBar rb, float rating, boolean fromUser){
textView.setText("Rating: " + ratingBar.getProgress());
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}

}

    <RingtonePreference
        android:key="pref_tone"
        android:title="@string/pref_tone"
        android:summary="@string/pref_tone_summ"
        android:showDefault="true"
        android:showSilent="true"/>

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
    <CheckBoxPreference
        android:key="pref_mute"
        android:title="@string/pref_mute"
        android:summary="@string/pref_mute_summ"
        android:defaultValue="false" />
    <EditTextPreference
        android:key="pref_textsize"
        android:title="@string/pref_textsize"
        android:dialogTitle="@string/pref_textsize_descr"
        android:summary="@string/pref_textsize_summ"
        android:defaultValue="14" />
    <ListPreference
        android:key="pref_theme"
        android:title="@string/pref_theme"
        android:dialogTitle="@string/pref_theme_descr"
        android:summary="@string/pref_theme_summ"
        android:entries="@array/theme_colors"
        android:entryValues="@array/theme_colors"
        android:defaultValue="Blue" />
    <RingtonePreference
        android:key="pref_tone"
        android:title="@string/pref_tone"
        android:summary="@string/pref_tone_summ"
        android:showDefault="true"
        android:showSilent="true"/>
</PreferenceScreen>

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="app_name">CodeForFood Test Two</string>
    <string name="pref_mute">Mute</string>
    <string name="pref_mute_summ">Disable all the sound in the application</string>
    <string name="pref_textsize">Text size</string>
    <string name="pref_textsize_descr">Enter text size</string>
    <string name="pref_textsize_summ">Set text size of the interface</string>
    <string name="pref_theme">Theme</string>
    <string name="pref_theme_descr">Pick a color</string>
    <string name="pref_theme_summ">Set the applications color theme</string>
    <string name="pref_tone">Ringtone</string>
    <string name="pref_tone_summ">Set ringtone</string>
    <string name="menu_settings">Settings</string>
    <string name="clear_settings">Reset settings</string>

</resources>

Toast.makeText(this, "Ringtone: " + prefs.getString("pref_tone", "none"), Toast.LENGTH_SHORT).show();

package com.example.codeforfoodtest_two;

import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends Activity{

static final int IDM_SETTINGS = 101;
public SharedPreferences prefs;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

Button btn_clear = (Button)findViewById(R.id.clearButton);
btn_clear.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View arg0) {
Editor editor = prefs.edit();
editor.clear();
editor.commit();
onResume();
}
});
}

@Override
public void onResume(){
prefs = PreferenceManager.getDefaultSharedPreferences(this);
if(prefs.getBoolean("pref_mute", false)){
Toast.makeText(this, "Muted!", Toast.LENGTH_SHORT).show();
}else{
Toast.makeText(this, "Not muted!", Toast.LENGTH_SHORT).show();
}
Toast.makeText(this, "Text size: " + prefs.getString("pref_textsize", "14"), Toast.LENGTH_SHORT).show();
Toast.makeText(this, "Theme color: " + prefs.getString("pref_theme", "Blue"), Toast.LENGTH_SHORT).show();
Toast.makeText(this, "Ringtone: " + prefs.getString("pref_tone", "none"), Toast.LENGTH_SHORT).show();

super.onResume();
}

@Override
public boolean onCreateOptionsMenu(Menu menu){
menu.add(Menu.NONE, IDM_SETTINGS, Menu.NONE, R.string.menu_settings);
return(super.onCreateOptionsMenu(menu));
}

@Override
public boolean onOptionsItemSelected(MenuItem item){
if(item.getItemId()==IDM_SETTINGS){
Intent intent = new Intent();
intent.setClass(this, TestPreferences.class);
startActivity(intent);
}
return true;
}
}

        <receiver android:name="TestReceiver" android:exported="true" android:enabled="true">
            <intent-filter>
                <action android:name="android.provider.Telephony.SMS_RECEIVED" />
            </intent-filter>
        </receiver>

    <uses-permission android:name="android.permission.RECEIVE_SMS" />
    <uses-permission android:name="android.permission.READ_SMS" />

package com.example.codeforfoodtest_two;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.telephony.SmsMessage;
import android.widget.Toast;

public class TestReceiver extends BroadcastReceiver {

@Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equals("android.provider.Telephony.SMS_RECEIVED")){
Bundle extras = intent.getExtras();
StringBuilder sb = new StringBuilder();

if(extras!=null){
Object[] pdus = (Object[])extras.get("pdus");
for(int i=0; i<pdus.length; i++){
SmsMessage smsMessage = SmsMessage.createFromPdu((byte[]) pdus[i]);
sb.append("
From: " + smsMessage.getOriginatingAddress());
sb.append("
From: " + smsMessage.getMessageBody());
}
}

Toast.makeText(context, "New SMS message" + sb.toString(), Toast.LENGTH_LONG).show();
}
}

}