Android中利用LinearLayout动态添加控件 - Androider的专栏 -...

在androidUI布局中，一般都是利用xml来布局控件，这是比较方便和直观的，但是有时却需要动态生成，下面就举2个简单例子来说明怎么动态添加控件：

1.动态添加2个垂直排列的Button

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01. @Override  
02.    public void onCreate(Bundle savedInstanceState) {  
03.        super.onCreate(savedInstanceState);  
04.       //setContentView(R.layout.main);        
05.       final LinearLayout layout2=new LinearLayout(this);  
06.        layout2.setOrientation(LinearLayout.VERTICAL);  
07.        Button btn1=new Button(this);  
08.        setContentView(layout2);  
09.        Button btn2=new Button(this);  
10.        btn1.setText("Button1");  
11.        btn2.setText("Button2");  
12.        layout2.addView(btn1);  
13.        layout2.addView(btn2);  
14.         
15.          
16.       setContentView(layout2);  
17.} 
 @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
       //setContentView(R.layout.main);     
       final LinearLayout layout2=new LinearLayout(this);
        layout2.setOrientation(LinearLayout.VERTICAL);
        Button btn1=new Button(this);
        setContentView(layout2);
        Button btn2=new Button(this);
        btn1.setText("Button1");
        btn2.setText("Button2");
        layout2.addView(btn1);
        layout2.addView(btn2);
      
       
       setContentView(layout2);
}

final LinearLayout layout2=new LinearLayou(this);

定义一个LinearLayout ，参数为context在这儿即为this

layout2.setOrientation(LinearLayout.VERTICAL);

设置layout格式为vertical，竖直排列

2.在Button的click事件中动态添加一个button

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·········10········20········30········40········50········60········70········80········90········100·······110·······120·······130·······140·······15001.OnClickListener listen1;  
02.   @Override 
03.   public void onCreate(Bundle savedInstanceState) {  
04.       super.onCreate(savedInstanceState);  
05.      //setContentView(R.layout.main);        
06.      final LinearLayout layout2=new LinearLayout(this);  
07.       layout2.setOrientation(LinearLayout.VERTICAL);  
08.       Button btn1=new Button(this);  
09.       setContentView(layout2);  
10.       Button btn2=new Button(this);  
11.       btn1.setText("Button1");  
12.       btn2.setText("Button2");  
13.       layout2.addView(btn1);  
14.       layout2.addView(btn2);         
15.       listen1 = new OnClickListener() {  
16.        public void onClick(View v) {  
17.            setTitle("点击button1 ");  
18.            Button btn3=new Button(v.getContext());  
19.            layout2.addView(btn3);  
20.            btn3.setText("Button3");  
21.              
22.              
23.        }  
24.    };  
25.     btn1.setOnClickListener(listen1);  
26.   } 
 OnClickListener listen1;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
       //setContentView(R.layout.main);     
       final LinearLayout layout2=new LinearLayout(this);
        layout2.setOrientation(LinearLayout.VERTICAL);
        Button btn1=new Button(this);
        setContentView(layout2);
        Button btn2=new Button(this);
        btn1.setText("Button1");
        btn2.setText("Button2");
        layout2.addView(btn1);
        layout2.addView(btn2);      
        listen1 = new OnClickListener() {
   public void onClick(View v) {
    setTitle("点击button1 ");
    Button btn3=new Button(v.getContext());
    layout2.addView(btn3);
    btn3.setText("Button3");
    
    
   }
  };
   btn1.setOnClickListener(listen1);
    }

与上一例子区别就是，在Button的OnClickListener中动态添加控件，需要注意的一点是 Button btn3=new Button(v.getContext);参数v.getContext为当前view的context，为什么例子1中用this作为context呢，呵呵，这是因为this即当前的activity，而activity又是context的子类，所以this就可以直接作为activity了。

查了下，context派生的类有：

java.lang.Object 
   android.content.Context
 Known Direct Subclasses
ContextWrapper , MockContext
ContextWrapper  Proxying implementation of Context that simply delegates all of its calls to another Context. 
MockContext  A mock Context class. 
 

 Known Indirect Subclasses

AbstractInputMethodService , Activity , ActivityGroup , AliasActivity , Application , ContextThemeWrapper , ExpandableListActivity , InputMethodService , IntentService , IsolatedContext , LauncherActivity , ListActivity , MockApplication , MutableContextWrapper , PreferenceActivity , RenamingDelegatingContext , Service , TabActivity

本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/zcpangzi/archive/2010/03/26/5420805.aspx

本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/zcpangzi/archive/2010/03/26/5420805.aspx

本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/zcpangzi/archive/2010/03/26/5420805.aspx