Android Lifecycle In-depth analysis (i) _android

The Android system adds hooks to the activity lifecycle, and we can do something with the hooks that are reserved for these systems.
Examples of 7 commonly used hooks are cited:
protected void OnCreate (Bundle savedinstancestate)
protected void OnStart ()
protected void Onresume ()
protected void OnPause ()
protected void OnStop ()
protected void Onrestart ()
protected void OnDestroy ()

Brief Description：
OnCreate (Bundle savedinstancestate): Called when an activity is created. The setting is http://www.myexception.cn/in the method, and the information needed to create the activity can be presented in bundle.
OnStart (): The activity becomes called when it is visible to the user on the screen, that is, when the focus is obtained.
Onresume (): The activity begins to be invoked when it interacts with the user (the method is always invoked, whether it is to start or restart a campaign).
OnPause (): The activity is called when the CPU and other resources are paused or retracted, which is used to save the active state.
OnStop (): Called when the activity is stopped and becomes invisible and subsequent life cycle events, that is, when the focus is lost.
Onrestart (): Called when the activity is restarted. The activity is still on the stack, java.io.UnsupportedEncodingException rather than starting a new activity.
OnDestroy (): Called when an activity is completely removed from system memory, the method may be invoked because someone calls the finish () method directly or the system decides to stop it to free resources.

switch at the same screen
1 Switch to horizontal screen
Onsaveinstancestate
OnPause
OnStop
OnDestroy
OnCreate
OnStart
Onrestoreinstancestate
Onresume

2 Switch to the vertical screen, destroyed two times
Onsaveinstancestate
OnPause
OnStop
Ondestroyoncreate
OnStart
Onrestoreinstancestate
Onresume
Onsaveinstancestate
OnPause
OnStop
OnDestroy
OnCreate
OnStart
Onrestoreinstancestate
Onresume

3 Modify Androidmanifest.xml, add the activity android:configchanges= "orientation", cut the horizontal screen, only destroy once
Onsaveinstancestate
OnPause
OnStop
OnDestroy
OnCreate
OnStart
Onrestoreinstancestate
Onresume

4 and then cut back to the vertical screen, found that no longer print the same information, but print more than one line onconfigchanged
Onsaveinstancestate
OnPause
OnStop
OnDestroy
OnCreate
OnStart
Onrestoreinstancestate
Onresume
Onconfigurationchanged

5 Change android:configchanges= "orientation" changed toAndroid:configchanges= "Orientation|keyboardhidden", cut horizontal screen, only print onconfigchanged
Onconfigurationchanged

6 cut back to the vertical screen
Onconfigurationchanged
Onconfigurationchanged

Summary：
1, do not set the activity of the android:configchanges, the screen will recall each life cycle, cut the horizontal screen will be executed once, cut the vertical screen will be executed twice
2, set the activity of the android:configchanges= "orientation", cut screen or will recall the life cycle, cut horizontal, vertical screen will only perform once
3, set the activity of the android:configchanges= "Orientation|keyboardhidden", the screen will not recall each life cycle, will only execute the Onconfigurationchanged method