Android : Using a Spinner with custom object

Spinners is really easy to work with if you just need to display your object with it's toString() function.

First a simple layout: 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
    <Button android:id="@+id/buttonPopulate"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Simple Spinner with custom data" />
    <Spinner  android:id="@+id/mySpinner"
              android:layout_width="fill_parent"
              android:layout_height="wrap_content"/>
    <Button android:id="@+id/buttonUseItem"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Use Selection"/>
    <TextView android:id="@+id/myTextView"
              android:layout_height="wrap_content"
              android:layout_width="wrap_content"/>
</LinearLayout>

Next up, a simple class to populate our Spinner with!

public class CountryInfo {
    private String countryName;
    private long countryPopulation;
    
    public CountryInfo(String cName, long cPopulation)
    {
        countryName = cName;
        countryPopulation = cPopulation;
    }
    
    public String getCountryName()
    {
        return countryName;
    }

    public long getCountryPopulation()
    {
        return countryPopulation;
    }

    public String toString()
    {
        return countryName;
    }
}

No odd behavior here, and last our SpinnerTest class

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.*;
import java.util.ArrayList;

public class SpinnerTest extends Activity
{
    
    Button button_UseSelectedItem;
    Spinner mySpinner;
    TextView myTextView;
    ArrayList<CountryInfo> myCountries;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        myCountries = populateList();
        setContentView(R.layout.main);
        mySpinner = (Spinner) findViewById(R.id.mySpinner);
        button_UseSelectedItem = (Button) findViewById(R.id.buttonUseItem);
        myTextView = (TextView) findViewById(R.id.myTextView);
        
        ArrayAdapter<CountryInfo> myAdapter = new ArrayAdapter<CountryInfo>(this, android.R.layout.simple_spinner_item, myCountries);
        mySpinner.setAdapter(myAdapter);
        
        button_UseSelectedItem.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                // Can also use mySpinner.setOnItemClickListener(......) 
                // Using a separate button here as there's often other data to select
                // or if you choose the wrong item.
                CountryInfo myCountry;
                if(!(mySpinner.getSelectedItem() == null))
                {
                    myCountry = (CountryInfo) mySpinner.getSelectedItem();
                    myTextView.setText(String.format("Country: " + myCountry.getCountryName() + "\t Population: " + myCountry.getCountryPopulation()))
            }
        });
    }

    public ArrayList<CountryInfo> populateList()
    {
        ArrayList<CountryInfo> myCountries = new ArrayList<CountryInfo>();
        myCountries.add(new CountryInfo("USA", 308745538));
        myCountries.add(new CountryInfo("Sweden", 9482855));
        myCountries.add(new CountryInfo("Canada", 34018000));
        return myCountries;
    }
}


Simple! Just using the internal android.R.layout.simple_spinner_item layout, remember to create a toString() for your custom object.

Link to source for android.R.layout_simple_spinner_item




I'll add another post later for customizing your spinner and adapter.