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Android中利用LinearLayout动态添加控件
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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

 @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

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

Known Indirect Subclasses

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

文章转自:http://blog.csdn.net/zcpangzi/article/details/5420805

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发帖于6年前 0回/6K+阅
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