Lists configuration changes that the activity will handle itself. When a configuration change occurs at runtime, the activity is shut down and restarted by default, but declaring a configuration with this attribute will prevent the activity from being restarted. Instead, the activity remains running and itsonConfigurationChanged()method is called.

http://developer.android.com/guide/topics/manifest/activity-element.html

以下引用写的很不错的网文：http://www.cnblogs.com/and_he/archive/2011/05/24/2055087.html

一般在AndroidManifest.xml文件中都没有使用到android:configChanges="keyboardHidden|orientation"配置，当然还是很有用的哈

就是如果配置了这个属性，当我们横竖屏切换的时候会直接调用onCreate方法中的onConfigurationChanged方法，而不会重新执行onCreate方法，那当然如果不配置这个属性的话就会重新调用onCreate方法了，下面是测试

AndroidManifest.xml文件

                                    <?                    xml version="1.0" encoding="utf-8"                    ?>                    
                    <                    manifest                     xmlns:android                    ="http://schemas.android.com/apk/res/android"                    
 package                    ="com.test"                    
 android:versionCode                    ="1"                    
 android:versionName                    ="1.0"                    >                    
                     <                    uses-sdk                     android:minSdkVersion                    ="8"                                         />                    

                     <                    application                     android:icon                    ="@drawable/icon"                     android:label                    ="@string/app_name"                    >                    
                     <                    activity                     android:name                    =".TestActivity"                    
 android:label                    ="@string/app_name"                    
 android:configChanges                    ="keyboardHidden|orientation"                    >                    
                     <                    intent-filter                    >                    
                     <                    action                     android:name                    ="android.intent.action.MAIN"                                         />                    
                     <                    category                     android:name                    ="android.intent.category.LAUNCHER"                                         />                    
                     </                    intent-filter                    >                    
                     </                    activity                    >                    

                     </                    application                    >                    
                    </                    manifest                    >                

main.xml文件

                                    <?                    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:id                    ="@+id/tv"                    
 android:layout_width                    ="fill_parent"                     
 android:layout_height                    ="wrap_content"                     
 android:text                    ="横竖屏切换测试"                    
                     />                    
                     <                    EditText 
                     android:layout_width                    ="fill_parent"                     
 android:layout_height                    ="wrap_content"                     
 android:id                    ="@+id/et"                    
                     />                    
                    </                    LinearLayout                    >                

TestActivity.java文件

                                    package                     com.test;

                    import                     android.app.Activity;
                    import                     android.content.res.Configuration;
                    import                     android.os.Bundle;
                    import                     android.widget.EditText;
                    import                     android.widget.TextView;

                    public                                         class                     TestActivity                     extends                     Activity {
 EditText et;
 TextView tv;
 @Override
                     public                                         void                     onCreate(Bundle savedInstanceState) {
                     super                    .onCreate(savedInstanceState);
 setContentView(R.layout.main);
 et                     =                     (EditText) findViewById(R.id.et);
 tv                     =                     (TextView) findViewById(R.id.tv);
 System.out.println(                    "                    我是onCreate方法                    "                    );
 }
 @Override
                     public                                         void                     onConfigurationChanged(Configuration newConfig) {
                     super                    .onConfigurationChanged(newConfig);
                     if                    (newConfig.orientation                     ==                     Configuration.ORIENTATION_LANDSCAPE){
 tv.setText(                    "                    横屏                    "                    );
 }                    else                    {
 tv.setText(                    "                    竖屏                    "                    );
 }
 
 }
}