IOS RunLoop, iosrunloop

IOS RunLoop, iosrunloop

• What is RunLoop?
  • Running cycle
  • A thread corresponds to a RunLoop. The main thread's RunLoop is started by default, and the Child thread's RunLoop must be started manually (call the run method)
  • RunLoop can be started in only one Mode. If no Source (Sources0, Sources1) or Timer exists in the current Mode, exit RunLoop directly.

• RunLoop Function

  • Keep programs running continuously
  • Process various events in the App (such as touch events, Timer events, Selector events)
  • CPU resources are saved and program performance is improved: When you do things, you need to rest ......

• Simulate the internal implementation of RunLoop

  • In fact, it is a do-while loop in which various tasks (such as Source, Timer, and Observer) are continuously processed)

  • Void message (int num) {printf ("execute the % I task", num);} int main (int argc, const char * argv []) {do {printf ("is there a problem? I slept "); int number; scanf (" % I ", & number); message (number);} while (1); return 0 ;}

 

• Get RunLoop object

  • RunLoop object
    • Nsunloop
    • CFRunLoopRef
  • Foundation

    [Nsunloop currentRunLoop]; // obtain the RunLoop object of the current thread [nsunloop mainRunLoop]; // obtain the RunLoop object of the main thread

  • Core Foundation

    CFRunLoopGetCurrent (); // obtain the RunLoop object CFRunLoopGetMain () of the current thread; // obtain the RunLoop object of the main thread

• RunLoop Structure

• The RunLoop object corresponding to CFRunLoopRef
  • CFRunLoopModeRef indicates the running Mode of RunLoop. By default, five modes are registered.
    • NSDefaultRunLoopMode: Default Mode of the App. Generally, the main thread runs in this Mode.
    • UITrackingRunLoopMode: interface tracking Mode, used for ScrollView tracking touch sliding, ensure that the interface sliding is not affected by other modes
    • Nsunloopcommonmodes: This is a placeholder Mode, not a real Mode
  • CFRunLoopTimerRef is a time-based trigger.
    • CFRunLoopTimerRef basically refers to NSTimer, which is affected by the RunLoop Mode.
  • CFRunLoopSourceRef is the event source (input source)
  • CFRunLoopObserverRef is an observer and can monitor the status change of RunLoop.

  • // 1. create Observer // The first parameter: memory used to allocate the observer object // The second parameter: used to set the event to be followed by the observer // The third parameter: this parameter is used to identify whether the observer is executed when it first enters the run loop or when it enters the run loop processing. // The fourth parameter is used to set the priority of the observer. // The Fifth parameter: the callback block CFRunLoopObserverRef observer = callback (CFAllocatorGetDefault (), callback, YES, 0, ^ (callback observer, CFRunLoopActivity activity) {switch (activity) {case kCFRunLoopEntry: NSLog (@ "Coming Soon loop"); break; case kCFRunLoopBeforeTimers: NSLog (@ "Coming Soon timers"); break; case kCFRunLoopBeforeSources: NSLog (@ "Coming Soon sources "); break; case kCFRunLoopBeforeWaiting: NSLog (@ "coming to sleep"); break; case kCFRunLoopAfterWaiting: NSLog (@ "waking up from sleep"); break; case kCFRunLoopExit: NSLog (@ "about to exit loop"); break; default: break ;}}); // 2. add listener/* First parameter: The RunLoop to which the listener is added. Second parameter: The Observer object to be added. Third parameter: In which mode the listener */CFRunLoopAddObserver (CFRunLoopGetMain (), observer, kCFRunLoopDefaultMode); // 3. Release observer CFRelease (observer );

     

• RunLoopRunLoop processing logic
• RunLoopRunLoop Application
  • NSTimer
    • It can only be run under the specified model

    • NSTimer *timer = [NSTimer timerWithTimeInterval:1.0 target:self selector:@selector(test) userInfo:nil repeats:YES];[[NSRunLoop currentRunLoop] addTimer:timer forMode:NSDefaultRunLoopMode];

  • ImageView display
    • You can only set images under the specified model.
  • PerformSelector
    • Can only be called under the specified model

    • [self.imageView performSelectorOnMainThread:@selector(setImage:) withObject:[UIImage imageNamed:@"lnj"] waitUntilDone:YES modes:@[NSDefaultRunLoopMode]];

       

  • Resident thread
    • You must call run to execute an endless loop.
    • Source/timer must be included in the model of nsunloop, so that the endless loop will not exit.

    • NSRunLoop *runloop = [NSRunLoop currentRunLoop];[runloop addPort:[NSMachPort port] forMode:NSDefaultRunLoopMode];[runloop run]

       

  • Auto Release pool

    • Activities = 0x1 = 11: about to enter RunLoop: create an automatic release pool activities = 0xa0 = 160 = 128 + 3232: about to sleep: Release the previous automatic release pool, create a new auto release pool 128: About to exit RunLoop: Release Auto Release pool