nstimer

This question already has answers here : Unrecognized selector sent to instance NSTimer Swift (3 answers) Closed 4 years ago . I'm making an app where you need to indicate the amount of time that a label appears for and that amount of time is counted down at the bottom of the page. When I run my app on the Xcode simulator, the chronometre label displays "Optional (*indicated number)" when I want it to only display the indicated number. Once it's displayed for a second, I get taken to my App Delegate and it says Thread 1: signal SIGABRT . The following error is also shown: 2015-02-22 21:05:50

定时器在项目中还是经常用到的，很多情况下为了省事我们都是在主线程中直接用，但这样经常会造成阻塞，影响定时器的准确性，对时间精度要求比较高的地方还会给人很不好的体验，比如卡顿等等，所以，定时器的使用最好放在子线程中，下面就记录几种定时器的用法： 1、NSThread NSThread *thread = [[NSThread alloc] initWithTarget:self selector:@selector(newThread) object:nil]; [thread start]; - (void)newThread{ @autoreleasepool{ [NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(requestMessages) userInfo:nil repeats:YES]; [[NSRunLoop currentRunLoop] run]; } } 2、GCD 首先定义timer： 这里有一点疑惑：timer若作为成员变量（定义放在@interface里面）定时器可以正常使用，但是在方法里面再去定义的定义的话定时器就完全不起作用了，还请知道的原因的小伙伴多多指教： NSTimeInterval period = 60.0; //设置时间间隔 dispatch

iOS里面使用的定时器类型一般有三种NSTimer、CADisplayLink、GCD。 1、最精准的定时器 - GCD #import "ViewController.h" @interface ViewController () // 必须要有强引用，不然对象会被释放 @property (nonatomic , strong) dispatch_source_t timer ; @end @implementation ViewController -(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{ NSLog(@"__%s__",__func__); #warning 重复执行的GCD定时器 // 1、基于GCD的定时器，创建timer对象： // 参数一：source的类型DISPATCH_SOURCE_TYPE_TIMER 表示定时器类型 // 参数二：描述内容，比如线程ID // 参数三：详细描述内容 // 参数四：队列,决定GCD的队列在哪个线程执行 dispatch_source_t timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, dispatch_get_global_queue(0

I've read up a lot about NSTimers, but I must be doing something very wrong with them, because it's practically all the leaks that show up in the Leaks Instrument. The "Responsible Frame" column says -[NSCFTimer or +[NSTimer(NSTimer). So here's how I have an NSTimer set up in my main menu. I shortened it up to just show how the timer is setup. .h - @interface MainMenu : UIView { NSTimer *timer_porthole; } @end @interface MainMenu () -(void) onTimer_porthole:(NSTimer*)timer; @end .m - (in initWithFrame) - (id)initWithFrame:(CGRect)frame { self = [super initWithFrame:frame]; if (self) { timer

Is there any way to run NSTimer for more than 3 mins in background? I have to create simple app that uses `locationManager(manager: CLLocationManager, didRangeBeacons beacons: [CLBeacon], inRegion region: CLBeaconRegion)` for scan my beacons. I have run into problem when I needed to check if user is exactly 10 seconds near closest beacon. I created var timer: NSTimer? var lastClosestBeacon: CLBeacon? { didSet { timer?.invalidate() timer = NSTimer.scheduledTimerWithTimeInterval(10, target: self, selector: "showLocalNotification", userInfo: nil, repeats: false) // NSRunLoop.mainRunLoop()