Just bought the Dongsheng teacher's iOS book, to record what they feel useful;
As a delegate object for an application, Appdeletage calls different methods at different stages of the application's life cycle.
Let's start by saying the iOS app's v status:
- Not Running (non-running) application is not running or has been terminated
- Inactive (foreground inactive) application enters foreground state, but cannot accept event handling
- Active (foreground active status) application enters foreground to accept events
- The Background (background state) application enters the background and is still able to execute code. If there is executable code will continue to execute, if not, will go into the suspended state
- Suspended (hang State) cannot execute code if system memory is not sufficient application will be terminated
iOS applications during these state transitions, the iOS system invokes some methods of appdelegate and sends notifications.
Here are some main ways to say it;
-(BOOL) Application: (uiapplication *) application didfinishlaunchingwithoptions: ( Nsdictionary *) launchoptions
program startup and initialization is called by the
-(void) applicationwillresignactive: (uiapplication *) application
Called when the program moves from the active state to an inactive state
-(void) Applicationdidenterbackground: (uiapplication *) application
This method is called when the program enters the background
-(void) Applicationwillenterforeground: (uiapplication *) application
This method is called when the program enters the foreground but is not yet active
-(void) applicationdidbecomeactive: (uiapplication *) application
Called when the program enters the foreground and is active
-(void) Applicationwillterminate: (uiapplication *) application
Called when the application is terminated
The above 6 methods are automatically generated in APPDEGATE.M;Non-running state---Start scenario program starts with a total of 3 statesNot running->inactive->activeIn the not running->inactive stage the system calls(BOOL) Application: (uiapplication*) Application didfinishlaunchingwithoptions: (nsdictionary*) Launchoptionsin the inactive->active phase, the system calls(void) applicationdidbecomeactive: (uiapplication *) ApplicationClick the Home button---App exit scenario in this case, there are two cases: 1, can be suspended in the background 2, not in the back of the table first said that a total of 4 states experienceactive->inactive->background->suspendedActive->inactive Phase Call(void) Applicationwillresignactive: (uiapplication*) Application
Inactive->background StageThis phase does not invoke the methods listed abovebackground->suspended Phase Call (void) Applicationdidenterbackground: (uiapplication *) application
The second caseActive->inactive->background->suspended->not RunningV Status
The active->inactive system does not invoke the above method, which is different from the first case
Inactive->background StageThis phase does not invoke the methods listed abovebackground->suspended Phase Call(void) Applicationdidenterbackground: (uiapplication *) ApplicationSuspended->not Running Call(void) Applicationwillterminate: (uiapplication*) Application
Suspend re-run scenariosuspended->background->inactive->activeSuspended->background This method is not called here
Background->inactive Call
Applicationwillenterforeground: (uiapplication*) Application
Inactive->active Call
(void) applicationdidbecomeactive: (uiapplication *) application
Memory Purge---Scenario termination the application is running in the background (hangs), and if the system emits a low memory warning, the memory terminator is cleared to meet the memory requirements of other applications. Background->suspended->not running (background->suspended is a pending state after the program has run out of code) in this case the system will not call any method;
IOS app life cycle
