Android中利用LinearLayout动态添加控件

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

[c-sharp] view plaincopy
 @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

[java:showcolumns] view plaincopy
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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
 Known Indirect Subclasses

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