Spinner

Layout

<Spinner
        android:id="@+id/label_spinner"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" android:layout_margin="8dp"/>

Implement OnItemSelected

public class Widgets extends AppCompatActivity implements
        AdapterView.OnItemSelectedListener{

String array

<string-array name="labels_array">
    <item>Home</item>
    <item>Work</item>
    <item>Mobile</item>
    <item>Other</item>
</string-array>

Java code

Spinner spinner = findViewById(R.id.label_spinner);

    spinner.setOnItemSelectedListener(this);
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this,
        R.array.labels_array, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource
        (android.R.layout.simple_spinner_dropdown_item);

    spinner.setAdapter(adapter);

Overriding methods

@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
    String spinner_item = parent.getItemAtPosition(position).toString();
    Toast.makeText(this, spinner_item, Toast.LENGTH_SHORT).show();
}

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

}