ios - 背景后 NSTimer 滞后

Question

timer = [NSTimer bk_timerWithTimeInterval:60 block:^(NSTimer *timer) { ....} repeats:YES];
[[NSRunLoop currentRunLoop] addTimer:timer forMode:NSDefaultRunLoopMode];


+ (id)bk_timerWithTimeInterval:(NSTimeInterval)inTimeInterval block:(void (^)(NSTimer *timer))block repeats:(BOOL)inRepeats
{
    NSParameterAssert(block != nil);
    return [self timerWithTimeInterval:inTimeInterval target:self selector:@selector(bk_executeBlockFromTimer:) userInfo:[block copy] repeats:inRepeats];
}

+ (void)bk_executeBlockFromTimer:(NSTimer *)aTimer {
    void (^block)(NSTimer *) = [aTimer userInfo];
    if (block) block(aTimer);
}

如果我在几分钟后折叠和展开应用程序，计时器几乎总是立即触发，有时它会延迟触发。为什么定时器并不总是立即工作？

Answer 1

尝试在您的 Appdelegate 的“didFinishLaunchingWithOptions”中添加这个

__block UIBackgroundTaskIdentifier locationUpdater =[[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{

        [[UIApplication sharedApplication] endBackgroundTask:locationUpdater];

        locationUpdater=UIBackgroundTaskInvalid;

    } ];