Fragment和Activity生命周期以及横竖屏切换对生命周期的影响

Fragment生命周期图解，fragment和activity生命周期对比

生命周期变化 : 切换到该Fragment

05-21 14:26:35.095: D/FragmentDemo(7649): onAttach
05-21 14:26:35.095: D/FragmentDemo(7649): onCreate
05-21 14:26:35.095: D/FragmentDemo(7649): onCreateView
05-21 14:26:35.100: D/FragmentDemo(7649): onActivityCreated
05-21 14:26:35.120: D/FragmentDemo(7649): onStart
05-21 14:26:35.120: D/FragmentDemo(7649): onResume

屏幕灭掉：
05-21 14:27:35.185: D/FragmentDemo(7649): onPause
05-21 14:27:35.205: D/FragmentDemo(7649): onSaveInstanceState
05-21 14:27:35.205: D/FragmentDemo(7649): onStop

屏幕解锁
05-21 14:33:13.240: D/FragmentDemo(7649): onStart
05-21 14:33:13.275: D/FragmentDemo(7649): onResume

切换到其余Fragment:
05-21 14:33:33.655: D/FragmentDemo(7649): onPause
05-21 14:33:33.655: D/FragmentDemo(7649): onStop
05-21 14:33:33.660: D/FragmentDemo(7649): onDestroyView

切换回自己的Fragment:
05-21 14:33:55.820: D/FragmentDemo(7649): onCreateView
05-21 14:33:55.825: D/FragmentDemo(7649): onActivityCreated
05-21 14:33:55.825: D/FragmentDemo(7649): onStart
05-21 14:33:55.825: D/FragmentDemo(7649): onResume

回到桌面
05-21 14:34:26.590: D/FragmentDemo(7649): onPause
05-21 14:34:26.880: D/FragmentDemo(7649): onSaveInstanceState
05-21 14:34:26.880: D/FragmentDemo(7649): onStop

回到应用
05-21 14:36:51.940: D/FragmentDemo(7649): onStart
05-21 14:36:51.940: D/FragmentDemo(7649): onResume

退出应用
05-21 14:37:03.020: D/FragmentDemo(7649): onPause
05-21 14:37:03.155: D/FragmentDemo(7649): onStop
05-21 14:37:03.155: D/FragmentDemo(7649): onDestroyView
05-21 14:37:03.165: D/FragmentDemo(7649): onDestroy

05-21 14:37:03.165: D/FragmentDemo(7649): onDetach

新建一个Activity，在各个生命周期中输出log
一、按crtl+f12切换成横屏时
onSaveInstanceState-->
onPause-->
onStop-->
onDestroy-->
onCreate-->
onStart-->
onRestoreInstanceState-->
onResume-->

二、再按crtl+f12切换成竖屏时，发现打印了两次相同的log
onSaveInstanceState-->
onPause-->
onStop-->
onDestroy-->
onCreate-->
onStart-->
onRestoreInstanceState-->
onResume-->
onSaveInstanceState-->
onPause-->
onStop-->
onDestroy-->
onCreate-->
onStart-->
onRestoreInstanceState-->
onResume-->

三、修改AndroidManifest.xml，把该Activity添加 Android:configChanges="orientation"，执行步骤2，横屏切换为竖屏
onSaveInstanceState-->
onPause-->
onStop-->
onDestroy-->
onCreate-->
onStart-->
onRestoreInstanceState-->
onResume-->

四、再执行步骤2，竖屏切换为横屏，发现不会再打印相同信息，但多打印了一行onConfigChanged
onSaveInstanceState-->
onPause-->
onStop-->
onDestroy-->
onCreate-->
onStart-->
onRestoreInstanceState-->
onResume-->
onConfigurationChanged-->

五、把步骤3的android:configChanges="orientation" 改为 android:configChanges="orientation|keyboardHidden"，执行步骤2，竖屏切换横屏，就只打印onConfigChanged
onConfigurationChanged-->

八、再次执行步骤2，横屏切换回竖屏
onConfigurationChanged-->

 总结：
一、不设置Activity的android:configChanges时，切屏会从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

二、设置Activity的android:configChanges="orientation"时，切屏仍是会从新调用各个生命周期，切横、竖屏时只会执行一次
 

三、设置Activity的android:configChanges="orientation|keyboardHidden"时，切屏不会从新调用各个生命周期，只会执行onConfigurationChanged方法