spinner allows us to have 1 available picker like this:

To be able to set the values ​​for spinner I have 2 how to perform the preset value in the file res / values ​​/ strings.xml or placed directly in your * .java.

First we do 1 the simple interface.
file *.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <LinearLayout 
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
	    <TextView 
	        android:layout_width="match_parent"
	        android:layout_height="wrap_content"
	        android:gravity="center_horizontal"
	        android:text="My Spinner 1"/>
    </LinearLayout>
    
    <LinearLayout 
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
	    <Spinner 
	        android:id="@+id/spin"
	        android:layout_width="wrap_content"
	        android:layout_height="wrap_content"
	        android:gravity="center_horizontal"/>
    </LinearLayout>
    
</LinearLayout>

Then we can look in the Graphics tab cal following form (bad breath but after run will look like the image above)

Next we install the value in the spinner:

How to 1: Install Now in Java.

package android.spinner;

import android.os.Bundle;
import android.app.Activity;
import android.widget.ArrayAdapter;
import android.widget.Spinner;

public class MainActivity extends Activity {
	Spinner sp;
	ArrayAdapter<String> adapter; //tạo vector adapter để truyền vào spinner
	String numbers[] = { "ONE", "TWO", "THREE", "FOUR", "FIVE", "SIX", "SEVEN", "EIGHT", "NINE", "TEN" };
	// number[] là các giá trị của spinner khi hiện ra
	public void onCreate(Bundle savedInstanceState){
		super.onCreate(savedInstanceState);
	   	setContentView(R.layout.activity_main);
	   	
	   	sp = (Spinner) findViewById(R.id.spin);
	   	//set các giá trị của number vào adapter
	   	adapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, numbers);
	   	//set adapter vào sp (spinner)
	 	sp.setAdapter(adapter);
	 }
}

The results of our:

How to 2: Install the values ​​from the file res / values ​​/ strings.xml

As well as interface installed on. We add the following code strings.xml file:

<string-array name = "day"> <!--Tên của mảng-->
	    <item>Monday</item>
	    <item>Tuesday</item>
	    <item>Wednesday</item>
	    <item>Thursday</item>
	    <item>Firday</item>
	    <item>Saturday</item>
	    <item>Sunday</item>
	</string-array>

Next, we work with the * .java

package android.spinner1;

import android.os.Bundle;
import android.app.Activity;
import android.widget.ArrayAdapter;
import android.widget.Spinner;

public class MainActivity extends Activity {
	ArrayAdapter<CharSequence> adapter;
	Spinner sp;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		sp = (Spinner) findViewById(R.id.spin);
		//Lấy giá trị của mảng "day" trong file string.xml bằng lệnh sau ("R.array.day" là tên mảng giá trị trong file string)
		adapter = ArrayAdapter.createFromResource(this, R.array.day, android.R.layout.simple_spinner_item); 
		//set các giá trị vào spinner
		sp.setAdapter(adapter);
	}
}

And our results: