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

@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

ContextWrapper, MockContext

ContextWrapperProxying implementation of Context that simply delegates all of its calls to another Context. MockContextA mock Context class. 

Known Indirect Subclasses

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