监测runloop

funloop.m

- (void)setupRunloopObserver
{
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        CFRunLoopRef runloop = CFRunLoopGetCurrent();
        
        CFRunLoopObserverRef enterObserver;
        enterObserver = CFRunLoopObserverCreate(CFAllocatorGetDefault(),
                                                kCFRunLoopEntry | kCFRunLoopExit,
                                                true,
                                                -0x7FFFFFFF,
                                                BBRunloopObserverCallBack, NULL);
        CFRunLoopAddObserver(runloop, enterObserver, kCFRunLoopCommonModes);
        CFRelease(enterObserver);
    });
}

static void BBRunloopObserverCallBack(CFRunLoopObserverRef observer, CFRunLoopActivity activity, void *info) {
    switch (activity) {
        case kCFRunLoopEntry: {
            NSLog(@"enter runloop...");
        }
            break;
        case kCFRunLoopExit: {
            NSLog(@"leave runloop...");
        }
            break;
        default: break;
    }
}