Using Spinners in Android studio

Spinners are used to display a drop down menu. On touching the spinner it displays all the items in the menu. Spinner shows its initial selected item in the default state. A user can select any item from the drop down menu.

Following code shows a spinner. A string array can be used to give items which can be created in string resource file. Android>App>res>values>strings.xml. A string resource file is below.

<resources>
    <string name="app_name">new check second</string>
    <string-array name="fruits">
        <item>Mango</item>
        <item>Orange</item>
        <item>Apple</item>
        <item>Guava</item>
        <item>Grapes</item>
    </string-array>
</resources>

The following code shows spinner in a constraint layout.

<androidx.constraintlayout.widget.ConstraintLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Spinner
        android:id="@+id/spinner"
        android:entries="@array/fruits"
        android:layout_width="215dp"
        android:layout_height="50dp"
        android:layout_marginTop="73dp"
        android:layout_marginBottom="608dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

Output:

The following code shows the items of spinner functioning with java code. ArrayAdapter can be used for such purposes. A strings.xml file is created with an array of items in a string resource file. Android>App>res>values>strings.xml.

<resources>
    <string name="app_name">Spinner</string>
    <string-array name="fruits">
        <item>Select</item>
        <item>Mango</item>
        <item>Orange</item>
        <item>Apple</item>
        <item>Guava</item>
        <item>Grapes</item>
    </string-array>
</resources>

The following code shows spinner widget in constraint layout.

<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Spinner
        android:id="@+id/spinner"
        android:layout_width="215dp"
        android:layout_height="50dp"
        android:layout_marginTop="250dp"
        android:layout_marginBottom="608dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

The items of the Spinner are placed using ArrayAdapter. The Java code shows a toast message on selection of different spinner items.

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity
        implements AdapterView.OnItemSelectedListener {

    Spinner spinner;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        spinner=(Spinner) findViewById(R.id.spinner);
        ArrayAdapter adapter = ArrayAdapter.createFromResource(this,R.array.fruits,android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(adapter);
        spinner.setOnItemSelectedListener(this);
    }


    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
        TextView fruitName= (TextView) view;
        spinner.setSelection(position);
        switch (position){
            case 0:
                Toast.makeText(this,"Select from menu",Toast.LENGTH_SHORT).show();
                break;
            case 1:
                Toast.makeText(this,"You have selected the fruit "+fruitName.getText(),Toast.LENGTH_SHORT).show();
                break;
            case 2:
                Toast.makeText(this,"You have selected the fruit "+fruitName.getText(),Toast.LENGTH_SHORT).show();
                break;
            case 3:
                Toast.makeText(this,"You have selected the fruit "+fruitName.getText(),Toast.LENGTH_SHORT).show();
                break;
            case 4:
                Toast.makeText(this,"You have selected the fruit "+fruitName.getText(),Toast.LENGTH_SHORT).show();
                break;
            case 5:
                Toast.makeText(this,"You have selected the fruit "+fruitName.getText(),Toast.LENGTH_SHORT).show();
                break;
        
        }
    }

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

    
    }
}