Create spinner with strings taken from resource folder (res >> value folder). On changing spinner value, change background of screen.

Activity_Main.xml:

<RelativeLayout 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"

    tools:context=".MainActivity" >

    <Spinner

        android:id="@+id/spinner1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentTop="true"

        android:layout_centerHorizontal="true"

        android:entries="@array/S"

        />

    <ImageView

        android:id="@+id/imageView1"

        android:layout_width="fill_parent"

        android:layout_height="fill_parent"

        android:layout_alignTop="@+id/imageView1"

        android:layout_marginTop="32dp"

        android:layout_toRightOf="@+id/imageView1" />

</RelativeLayout>

MainActivity.java

package com.example.prac12;

import android.os.Bundle;

import android.app.Activity;

import android.view.Menu;

import android.view.View;

import android.widget.AdapterView;

import android.widget.AdapterView.OnItemSelectedListener;

import android.widget.ImageView;

import android.widget.Spinner;

import android.widget.Toast;

public class MainActivity extends Activity implements OnItemSelectedListener {

            Integer[] aIDS={

                                    R.drawable.one,

                                    R.drawable.two,

                                    R.drawable.three,

                                    R.drawable.four};

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

       

        Spinner sp = (Spinner) findViewById(R.id.spinner1);

        sp.setOnItemSelectedListener(this);

    }

    @Override

    public boolean onCreateOptionsMenu(Menu menu) {

        getMenuInflater().inflate(R.menu.activity_main, menu);

        return true;

    }

            @Override

            public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,long arg3) {

                        Toast.makeText(this,"SELECTED ITEM IS : "+arg0.getSelectedItem().toString(),Toast.LENGTH_SHORT).show();

                        ImageView ie = (ImageView) findViewById(R.id.imageView1);

                        ie.setImageResource(aIDS[arg2]);

            }

}