android加载include

例子一： 
sublayout.xml 

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:orientation="vertical" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:background="#505050" 
    > 
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="SubLayout" 
    /> 
<Button 
android:id="@+id/mybutton" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text=" A Button " 
    /> 
</LinearLayout> 

mail.xml 
<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:orientation="vertical" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    > 
<TextView 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello" 
    /> 
<include android:id="@+id/main1" layout="@layout/sublayout" /> 
<include android:id="@+id/main2" layout="@layout/sublayout" /> 
<Button 
    android:id="@+id/startanotheractivity" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text=" Start Another Activity " 
    /> 
</LinearLayout> 

如何调用组件include进来的组件呢。 

package com.AndroidIncludeLayout; 

import android.app.Activity; 
import android.content.Intent; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.Button; 
import android.widget.Toast; 

public class AndroidIncludeLayout extends Activity { 
    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.main); 
         
        View subLayout1 = (View)findViewById(R.id.main1); 
        View subLayout2 = (View)findViewById(R.id.main2); 
        Button myButton_main1 = (Button)subLayout1.findViewById(R.id.mybutton); 
        Button myButton_main2 = (Button)subLayout2.findViewById(R.id.mybutton); 
        Button startAnotherActivity = (Button)findViewById(R.id.startanotheractivity); 
         
        startAnotherActivity.setOnClickListener(new Button.OnClickListener(){ 

   @Override 
   public void onClick(View arg0) { 
    // TODO Auto-generated method stub 
    Intent intent = new Intent(); 
             intent.setClass(AndroidIncludeLayout.this, AnotherActivity.class); 
             startActivity(intent); 
     
   }}); 
         
        myButton_main1.setOnClickListener(new Button.OnClickListener(){ 

   @Override 
   public void onClick(View arg0) { 
    // TODO Auto-generated method stub 
    Toast.makeText(AndroidIncludeLayout.this, "Button 1 Pressed", Toast.LENGTH_LONG).show(); 
   }}); 
         
        myButton_main2.setOnClickListener(new Button.OnClickListener(){ 

   @Override 
   public void onClick(View arg0) { 
    // TODO Auto-generated method stub 
    Toast.makeText(AndroidIncludeLayout.this, "Button 2 Pressed", Toast.LENGTH_LONG).show(); 
   }}); 
    } 
} 
但是如果include进来的xml，是 
sublayout.xml 

<?xml version="1.0" encoding="utf-8"?> 
<merge xmlns:android="http://schemas.android.com/apk/res/android"> 
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="SubLayout" 
    /> 
<Button 
android:id="@+id/mybutton" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text=" A Button " 
    /> 
</merge> 

则以上的方法将不能实现，会报空指针。 
因为用了merge后，导入进来就相当于是当前view下的组件了，所以直接 

findViewById就可以了。