横竖屏切换时候activity的生命周期

通过以下部分代码,我们可以了解清楚Activity页面在横,竖屏切换时,生命周期的变化:

public class AndroidLifecycle extends Activity {

	public void onCreate(Bundle savedInstanceState) {
		System.out.println("First Activity =======onCreate()========");
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
	}

	@Override
	protected void onSaveInstanceState(Bundle outState) {
		System.out
				.println("First Activity =======onSaveInstanceState()========");
		super.onSaveInstanceState(outState);
	}

	@Override
	protected void onRestoreInstanceState(Bundle outState) {
		System.out
				.println("First Activity =======onRestoreInstanceState()========");
		super.onRestoreInstanceState(outState);
	}

	@Override
	public void onConfigurationChanged(Configuration newConfig) {
		System.out
				.println("First Activity =======onConfigurationChanged()========");
		super.onConfigurationChanged(newConfig);
	}

	// Called after onCreate — or after onRestart when the activity had been
	// stopped, but is now again being displayed to the user. It will be
	// followed by onResume
	protected void onStart() {
		System.out.println("First Activity =======onStart()========");
		super.onStart();
	}

	// Called after onRestoreInstanceState, onRestart, or onPause, for your
	// activity to start interacting with the user
	protected void onResume() {
		System.out.println("First Activity =======onResume()========");
		super.onResume();
	}

	// Called as part of the activity lifecycle when an activity is going into
	// the background, but has not (yet) been killed
	protected void onPause() {
		System.out.println("First Activity =======onPause()========");
		super.onPause();
	}

	// Called when you are no longer visible to the user. You will next receive
	// either onRestart, onDestroy, or nothing, depending on later user
	// activity.
	protected void onStop() {
		System.out.println("First Activity =======onStop()========");
		super.onStop();
	}

	// Perform any final cleanup before an activity is destroyed
	protected void onDestroy() {
		System.out.println("First Activity =======onDestroy()========");
		super.onDestroy();
	}

	// Called after onStop when the current activity is being re-displayed to
	// the user (the user has navigated back to it). It will be followed by
	// onStart and then onResume
	protected void onRestart() {
		System.out.println("First Activity =======onRestart()========");
		super.onRestart();
	}
}

AndroidMenifest.xml文件:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
	package="cn.d" android:versionCode="1" android:versionName="1.0">
	<!-- android:configChanges="orientation" -->
	<application android:icon="@drawable/icon" android:label="@string/app_name">
		<activity android:name=".AndroidLifecycle" android:label="@string/app_name"
			android:configChanges="orientation|keyboardHidden">
			<intent-filter>
				<action android:name="android.intent.action.MAIN" />
				<category android:name="android.intent.category.LAUNCHER" />
			</intent-filter>
		</activity>
	</application>
</manifest> 

通过以上代码,我们可以知道:
1.不设置Activity的android:configChanges时,切屏会重新调用各个生命周期,切横屏时会执行一次,切竖屏时会执行两次.

2.设置Activity的android:configChanges="orientation"时,切屏还是会重新调用各个生命周期,切横、竖屏时只会执行一次.

3.设置Activity的android:configChanges="orientation|keyboardHidden"时,切屏不会重新调用各个生命周期,只会执行onConfigurationChanged方法.