Android Spinners(Dropdownlist) tutorial with example

Android spinners are not nothing but the dropdownlist seen in other programming languages. It provides a easy way to select  value from  list. Clicking spinner will display a dropdownlist with the available values.
            Lets see this concept with an example, which is quite simple with very few lines of code.

Step 1
        -- Add a spinner object to your layout as shown below.

<Spinner
        android:id="@+id/spinnerstate"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp" />

       --  Add a text view control that displays the selected value from spinner.

Step 2
        --  Declare a string array which is going to be the source for the spinner.

private String[] state= {"Andra Pradesh","Arunachal Pradesh","Assam","Bihar","Haryana","Himachal Pradesh", "Jammu and Kashmir", "Jharkhand","Karnataka", "Kerala","Tamil Nadu"};

This source needs to be bound with the spinner through ArrayAdapter. We will be making use of the below constructor.

public ArrayAdapter (Context context, int resource, List<T> objects)

where we need to pass the current context, id, the objects to represent in the ListView - as shown below.

ArrayAdapter<String> adapter_state = new ArrayAdapter<String>(this,  android.R.layout.simple_spinner_item, state);

Step 3
         -- Set the layout resource to create the drop down views and bind it to spinner object
adapter_state.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

spinnerState.setAdapter(adapter_state);

          -- Set the spinner to listen to selected events.

spinnerState.setOnItemSelectedListener(this);

Step 4
        -- Once an item is selected, the below callback fucntion will get invoked and we need to perform user defined functions here. I have displayed the selected value.

public void onItemSelected(AdapterView<?> parent, View view, int position,long id)

Android Spinners

Selected value

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <Spinner
        android:id="@+id/osversions"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp" />

    <TextView
        android:id="@+id/selVersion"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_below="@+id/osversions"
        android:layout_marginLeft="10dp"
        android:layout_marginTop="20dp" />

</RelativeLayout>

Main_activity.java

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;

public class MainActivity extends Activity implements OnItemSelectedListener {
 Spinner spinnerOsversions;
 TextView selVersion;
 private String[] state = { "Cupcake", "Donut", "Eclair", "Froyo",
   "Gingerbread", "HoneyComb", "IceCream Sandwich", "Jellybean",
   "kitkat" };

  @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  System.out.println(state.length);
  selVersion = (TextView) findViewById(R.id.selVersion);
  spinnerOsversions = (Spinner) findViewById(R.id.osversions);
  ArrayAdapter<String> adapter_state = new ArrayAdapter<String>(this,
    android.R.layout.simple_spinner_item, state);
  adapter_state
    .setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
  spinnerOsversions.setAdapter(adapter_state);
  spinnerOsversions.setOnItemSelectedListener(this);

  }

  public void onItemSelected(AdapterView<?> parent, View view, int position,
   long id) {
  spinnerOsversions.setSelection(position);
  String selState = (String) spinnerOsversions.getSelectedItem();
  selVersion.setText("Selected Android OS:" + selState);
 }

  @Override
 public void onNothingSelected(AdapterView<?> arg0) {
  // TODO Auto-generated method stub

  }

}

Source code of this application:
AndroidSpinners