CFRunLoopObserverRef CFRunLoopObserverCreateWithHandler(CFAllocatorRef allocator, CFOptionFlags activities, Boolean repeats, CFIndex order, void (^block) (CFRunLoopObserverRef observer, CFRunLoopActivity activity))

參數(shù):

1.CFAllocatorRef allocator  //默認(rèn)值 CFAllocatorGetDefault()

2.CFOptionFlags activities  //監(jiān)聽(tīng)Runloop的什么狀態(tài)

3.Boolean repeats                 //是否重復(fù)YES/NO

4.CFIndex order                     //傳0

5.Block回調(diào)

RunLoop 狀態(tài)

typedef CF_OPTIONS(CFOptionFlags, CFRunLoopActivity) {

    kCFRunLoopEntry = (1UL << 0),                           //即將進(jìn)入Runloop

    kCFRunLoopBeforeTimers = (1UL << 1),             //即將執(zhí)行Timer

    kCFRunLoopBeforeSources = (1UL << 2),          //即將處理Sources

    kCFRunLoopBeforeWaiting = (1UL << 5),           //即將睡眠

    kCFRunLoopAfterWaiting = (1UL << 6),             //將從睡眠中喚醒

    kCFRunLoopExit = (1UL << 7),                           //即將退出

    kCFRunLoopAllActivities = 0x0FFFFFFFU        //所有都監(jiān)聽(tīng)

};

添加Runloop觀察者

void CFRunLoopAddObserver(CFRunLoopRef rl, CFRunLoopObserverRef observer, CFStringRef mode);

1.CFRunLoopRef rl     //監(jiān)聽(tīng)的runloop  如 CFRunLoopGetCurrent()

2.CFRunLoopObserverRef observer  //觀察者

3.CFStringRef mode    //Runloop模式

例子:

CFRunLoopObserverRef oberver = CFRunLoopObserverCreateWithHandler(CFAllocatorGetDefault(), kCFRunLoopAllActivities, YES, 0, ^(CFRunLoopObserverRef observer, CFRunLoopActivity activity) {

               NSLog(@"%zd",activity);  

    });    

    CFRunLoopAddObserver(CFRunLoopGetCurrent(), oberver, kCFRunLoopDefaultMode);