Spinner學習中一個簡單的例子。
main.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/info"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/city_prompt" />
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<Spinner
android:id="@+id/city"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:prompt="@string/city_prompt"
android:entries="@array/city_info"/>
<Spinner
android:id="@+id/area"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:prompt="@string/area_prompt"
/>
</LinearLayout>
</LinearLayout>string.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="hello">Hello World, SpinnerListenerActivity!</string>
<string name="app_name">SpinnerListener</string>
<string name="city_prompt">請選擇您喜歡的城市：</string>
<string name="area_prompt">請選擇您喜歡的城區：</string>
</resources>city_data.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string-array name="city_info">
<item >中國--武漢</item>
<item >中國--四川</item>
<item >中國--上海</item>
</string-array>
</resources>SpinnerListenerActivity.java:
package com.sample.spinnerlistener;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;
public class SpinnerListenerActivity extends Activity {
private TextView info = null;
private Spinner city = null;
private Spinner area = null;
private ArrayAdapter<CharSequence> areaAdapter = null;//添加到spinner area中
private String[][] areaData = new String[][]{//保存城區信息，與一級列表中的順序相同
{"武昌","漢陽","漢口"},
{"成都","資陽","樂山"},
{"黃浦","楊浦","閔行"}
};
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
super.setContentView(R.layout.main);
info = (TextView)this.findViewById(R.id.info);//獲取TextView組件
city = (Spinner)this.findViewById(R.id.city);//獲取spanner組件
area = (Spinner)this.findViewById(R.id.area);
/**
* 爲spinner註冊監聽事件，當選項改變時觸發，並將選項內容在TextView上顯示
*/
city.setOnItemSelectedListener(new OnItemSelectedListener() {
/**
* Callback method to be invoked when an item in this view has been selected.
* This callback is invoked only when the newly selected position is different from the previously selected position or if there was no selected item.
*
* Impelmenters can call getItemAtPosition(position) if they need to access the data associated with the selected item.
* Parameters
* parent The AdapterView where the selection happened
* view The view within the AdapterView that was clicked
* position The position of the view in the adapter
* id The row id of the item that is selected
*/
public void onItemSelected(AdapterView<?> parent, View view,
int position, long id) {
/**
* 實例化Adapter對象，並將一級列表中當前選中項所對應的子菜單內容areaData[position]封裝到Adapter對象中
*/
areaAdapter = new ArrayAdapter<CharSequence>(SpinnerListenerActivity.this, android.R.layout.simple_spinner_item, areaData[position]);
area.setAdapter(areaAdapter); //設置二級列表的內容
String text = parent.getItemAtPosition(position).toString();//獲取一級列表中選中項的內容
info.setText("您選擇的城市是："+text);
}
//沒有選中項是觸發
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
});
}結果：
