[Android SDK 入門] 3-4 勾選式控制項 - CheckBox

前言 : 
android.widget.CheckBox 控制項是用來多選使用的, 使用 isChecked() 方法來判斷是否被勾選, 當被勾選/沒被勾選時就可以依據使用情節做對應的動作, 這是 CheckBox 控制項的主要用法, 用來做為邏輯上或者判斷上的分岔. 

主要功能介紹 : 
在畫面上配置 8 個 CheckBox 控制項, 讓使用者自由地勾選, 當底下的Button 被按下後程式會檢查並橋接所有被勾選的 CheckBox 控制項上的文字並顯示於當前 Activity 的標題. 

範例代碼 : 
請依 3-1 節介紹設定好 main.xml (添加展示Button), ControlItemsDemo.java (添加展示Button 的監聽行為) 與 AndroidManifest.xml (註冊 CheckBox Activity). 

- SampleCheckBox.java : CheckBox demo 的 Activity

view plaincopy to clipboardprint?

1. package john.controlitems.demo;  
2.   
3. import android.app.Activity;  
4. import android.os.Bundle;  
5. import android.view.View;  
6. import android.widget.Button;  
7. import android.widget.CheckBox;  
8. import android.widget.Toast;  
9.   
10. public class SampleCheckBox extends Activity {  
11.     private Button btn_Select;  
12.     private CheckBox cb_Cloth;  
13.     private CheckBox cb_Entertain;  
14.     private CheckBox cb_Leisure;  
15.     private CheckBox cb_Electric;  
16.     private CheckBox cb_Cosmetic;  
17.     private CheckBox cb_Wholesalse;  
18.     private CheckBox cb_Services;  
19.     private CheckBox cb_Home;  
20.       
21.     @Override  
22.     public void onCreate(Bundle savedInstanceState) {  
23.         super.onCreate(savedInstanceState);  
24.         setContentView(R.layout.sample_check_box);  
25.         findViews();  
26.         addListener();  
27.     }  
28.       
29.     protected void findViews(){  
30.         btn_Select = (Button)findViewById(R.id.btn_Select);  
31.         cb_Cloth = (CheckBox)findViewById(R.id.cb_Cloth);  
32.         cb_Entertain = (CheckBox)findViewById(R.id.cb_Entertain);  
33.         cb_Leisure = (CheckBox)findViewById(R.id.cb_Leisure);  
34.         cb_Electric = (CheckBox)findViewById(R.id.cb_Electric);  
35.         cb_Cosmetic = (CheckBox)findViewById(R.id.cb_Cosmetic);  
36.         cb_Wholesalse = (CheckBox)findViewById(R.id.cb_Wholesalse);  
37.         cb_Services = (CheckBox)findViewById(R.id.cb_Services);  
38.         cb_Home = (CheckBox)findViewById(R.id.cb_Home);       
39.     }  
40.       
41.     protected void addListener(){  
42.         btn_Select.setOnClickListener(new Button.OnClickListener(){  
43.             @Override  
44.             public void onClick(View v) {  
45.                 String s_Checked="";  
46.                 if(cb_Cloth.isChecked()) {  
47.                     s_Checked += cb_Cloth.getText()+", ";  
48.                 }  
49.                 if(cb_Entertain.isChecked()) {  
50.                     s_Checked += cb_Entertain.getText()+", ";  
51.                 }  
52.                 if(cb_Leisure.isChecked()) {  
53.                     s_Checked += cb_Leisure.getText()+", ";  
54.                 }  
55.                 if(cb_Electric.isChecked()) {  
56.                     s_Checked += cb_Electric.getText()+", ";  
57.                 }  
58.                 if(cb_Cosmetic.isChecked()) {  
59.                     s_Checked += cb_Cosmetic.getText()+", ";  
60.                 }  
61.                 if(cb_Wholesalse.isChecked()) {  
62.                     s_Checked += cb_Wholesalse.getText()+", ";  
63.                 }  
64.                 if(cb_Services.isChecked()) {  
65.                     s_Checked += cb_Services.getText()+", ";  
66.                 }  
67.                 if(cb_Home.isChecked()) {  
68.                     s_Checked += cb_Home.getText()+", ";  
69.                 }  
70.                 setTitle("Black List: "+s_Checked);  
71.                 if(s_Checked.trim().length()>0) {  
72.                     Toast.makeText(SampleCheckBox.this, "設置黑名單成功!", Toast.LENGTH_LONG).show();   
73.                 }  
74.             }  
75.               
76.         });  
77.     }  
78. }  

顯示範例結果 : 
請在主程式畫面點擊按鈕 "勾選式控制項 - CheckBox" 進入 CheckBox demo Activity. 
Step1 : 請選取任意CheckBox 後點選按鈕 "確定" 
 
Step2 : 當前 Activity 的標題變更為點選 CheckBox 內容的疊接.