Spinner

步驟：
1. 在字串資源檔 strings.xml 中建立一個字串陣列，再把這個字串陣列設定給Spinner元件成為選單
<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="app_name">MyCardEmulation</string>
    ...
    <string array name="sex_list">
        <item>Male</item>
        <item>Female</item>
    </string array>   
    <string name="account_id_txt">Account Number:</string>
</resources>

2. 在 介面布局檔 layout.xml 中加入一個Spinner介面元件
<Spinner
        android:id="@+id/spnSex"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:entries="@array/sex_list"
        android:spinnerMode="dialog"                 // dialog or dropdown        android:prompt="@string/spn_sex_list_prompt" />       // prompt為 mode為dialog時使用

3. 在程式檔中取得這個 Spinner元件，並為它建立一個 OnItemSeclectedListener()事件處理程序
private Spinner mSpnSex;
private String msSex;
 @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    ...
    mSpnSex = (Spinner) findViewById(R.id.spnSex);
    mSpnSex.setOnItemSelectedListener(spnSexOnItemSelected);
}
private AdapterView.OnItemSelectedListener spnSexOnItemSelected =
      new AdapterView.OnItemSelectedListener() {
    @Override
    public void onItemSelected(AdapterView<?> parent, View v, int position, long id) {
        // TODO Auto-generated method stub
        msSex = parent.getSelectedItem().toString();
    }
    @Override
    public void onNothingSelected(AdapterView<?> parent) {
     // TODO Auto-generated method stub
    
    }
};