In this tutorial, we will work on the spinner.Spinner is used to select the data from a drop down menu.In this, we use dummy data to spinner for drop down menu

So, Let’s start:-

1.Open Eclipse or Android Studio -> New Project->Android Application Project-> Name of Application-> Follow all instructions and complete by clicking on Finish.

2.Create a layout for MainActivity.java that will be our main screen.

activity_main.xml

<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:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" 
    tools:context=".MainActivity"
    android:orientation="vertical">

    <TextView
        android:text="Countries"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" />
    
    <Spinner
        android:id="@+id/selectcountry"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"></Spinner>

</LinearLayout>

3. Now define MainActivity.java as follows

MainActivity.java

package com.coderzpassion.myspinnersample;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.Toast;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {
    //spinner
    Spinner countryspinner;
    //list to be set to spinner
    ArrayList<String> countries=new ArrayList<>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        countryspinner=(Spinner)findViewById(R.id.selectcountry);
        //prepare dummy data for spinner
        prepareDummyData();
        //adapter for spinner
        ArrayAdapter<String> adapter=new ArrayAdapter<String>(MainActivity.this,android.R.layout.simple_spinner_dropdown_item,android.R.id.text1,countries);
        //attach adapter to spinner
        countryspinner.setAdapter(adapter);

        //handle click of spinner item
        countryspinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {

                // clicked item will be shown as spinner
                Toast.makeText(getApplicationContext(),""+parent.getItemAtPosition(position).toString(),Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {

            }
    });

    }

    public void prepareDummyData()
    {
        countries.add("India");
        countries.add("Russia");
        countries.add("USA");
        countries.add("UK");
        countries.add("Australia");
    }

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

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.coderzpassion.myspinnersample" >

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

Output