AndroidでSpinner(listbox)を出す（固定値）

android:spinnerModeは"dialog"か"dropdown"のどちらかを選べる

activity_main.xml

    <Spinner
        android:id="@+id/spn"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:entries="@array/spn_items"
        android:prompt="@string/spn_prompt"
        android:spinnerMode="dialog"
        />

strings.xml

<resources>
    <string name="app_name">MyTest2</string>
    <string name="spn_prompt">MOSを選択して下さい</string>
    <string-array name="spn_items">
        <item>Windows</item>
        <item>Linux</item>
        <item>Mac</item>
    </string-array>
</resources>

MainActivity.java

public class MainActivity extends AppCompatActivity {

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

        Spinner sp = (Spinner)findViewById(R.id.spn);
        sp.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener(){
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id){
                Spinner sp = (Spinner) parent;
                Toast.makeText(MainActivity.this,
                        String.format("選択項目: %s", sp.getSelectedItem()),
                        Toast.LENGTH_SHORT).show();
            }

            public void onNothingSelected(AdapterView<?> parent){

            }
        });
    }
}