[AndroidUI development - five ways of writing event monitoring]

1. Specifically create an object that implements the xxx event listener interface, such as: Monitor1, and then button1.setOnXXX-Listener(monitor1); then [internal class]

   Button button1 = （Button）findViewById（R.id.button1）;
   
   class MyMonitor implements View.OnClickListener(){
         
         
   	
   	public void onClick(View v){
         
         
   		switch(v.getId()){
         
         
   			case R.id.button1 : button1.setText("我被单击了！"); break;
   			case.......
   		}
   		
   	}
   }
   
   MyMonitor myMonitor = new MyMonitor();					//创建监听器对象
   
   button1.setOnClickListener(myMonitor);					//为 button1，指定单击事件监听器对象
   

2. Implement the listener interface of the current class, and then button1.setOnXXX-Listener(this); Then the abstract method of the listener interface (that is, the event processing method) must be implemented in the current class.

3. Methods using anonymous inner classes

   	View.OnClickListener myMonitor = new View.OnClickListener(){
         
         		//myMonitor 为 接口类型的引用变量，用于指向实现了该接口类型的 实现类的 对象
   
   		@Override   	//@Override 注解 ： 一来便于阅读，二来防止写错重写方法，而被误认为是新方法。导致重写失败！】
   
   		public void onClick(View v){
         
         
   
   			button1.setText("我被单击了！");
   		}
   
   	}// 此处是 创建了一个匿名内部类 【注意 ()内部类中】
   
   	Button button1 = (Button) findViewById(R.id.button1);
   	
   	button1.setOnClickListener(myMonitor);
   

4. In fact, the principle is the same as method 3, but the code is simple! [Event adapters (or listeners) are also commonly specified in this way in java]

   Button button1 = （Button） findViewById(R.id.button1);
   
   button1.setOnClickListener(new View.OnClickListener(){
         
         		// 也是创建 实现了View.OnClickListener接口的 匿名内部类
   
   	@Override    //【在jdk1.6时才能这样写，否则就不能写@Override，因为1.6以下不支持实现接口中的方法时 使用@Override 】
   	public void onClick(View v){
         
         
   
   		button1.setText("我被单击了！");
   	}
   }); 
   

5. Use the reflection mechanism to achieve, neither find controls nor set listeners ------ but not recommended

   Set the onclick attribute for the (View) control in the layout file, and then write a method with the name of the onclick attribute value in the Activity corresponding to the layout. It must be
   public and pass a View type parameter. --------It is more suitable for simple tests. uncommonly used

   • layout file:

     	<Button
         android:onClick="onClickButton1"
         android:id="@+id/button1"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:text="利用反射机制触发事件处理方法" />
     

   • In XXXActivity:

     public void onClickButton1(View view){
             
             
     	Toast.makeText(MainActivity.this, "你点击了button1", Toast.LENGTH_SHORT).show();
     }