#import "MyViewController.h"

@interface MyViewController ()

@property (strong, nonatomic) NSTimer *timer;

@end

@implementation MyViewController

double timerInterval = 1.0f;

- (NSTimer *) timer {
    if (!_timer) {
        _timer = [NSTimer timerWithTimeInterval:timerInterval target:self selector:@selector(onTick:) userInfo:nil repeats:YES];
    }
    return _timer;
}

- (void)viewDidLoad
{
    [super viewDidLoad];

    [[NSRunLoop mainRunLoop] addTimer:self.timer forMode:NSRunLoopCommonModes];
}

-(void)onTick:(NSTimer*)timer
{
    NSLog(@"Tick...");
}

@end

#import "MyViewController.h"

@interface MyViewController ()

@property (strong, nonatomic) NSTimer *timer;

@end

@implementation MyViewController

double timerInterval = 1.0f;

- (NSTimer *) timer {
    if (!_timer) {
        _timer = [NSTimer timerWithTimeInterval:timerInterval target:self selector:@selector(onTick:) userInfo:nil repeats:YES];
    }
    return _timer;
}

- (void)viewDidLoad
{
    [super viewDidLoad];

    [[NSRunLoop mainRunLoop] addTimer:self.timer forMode:NSRunLoopCommonModes];
}

-(void)onTick:(NSTimer*)timer
{
    NSLog(@"Tick...");
}

@end

NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:60 target:self selector:@selector(timerCalled) userInfo:nil repeats:NO];

-(void)timerCalled
{
     NSLog(@"Timer Called");
     // Your Code
}

答案中缺少一个特定的时间，这里是下一个小时:

NSCalendarUnit allUnits = NSCalendarUnitYear   | NSCalendarUnitMonth |
                          NSCalendarUnitDay    | NSCalendarUnitHour  |
                          NSCalendarUnitMinute | NSCalendarUnitSecond;

NSCalendar *calendar = [[ NSCalendar alloc]  
                          initWithCalendarIdentifier:NSGregorianCalendar];

NSDateComponents *weekdayComponents = [calendar components: allUnits 
                                                  fromDate: [ NSDate date ] ];

[ weekdayComponents setHour: weekdayComponents.hour + 1 ];
[ weekdayComponents setMinute: 0 ];
[ weekdayComponents setSecond: 0 ];

NSDate *nextTime = [ calendar dateFromComponents: weekdayComponents ];

refreshTimer = [[ NSTimer alloc ] initWithFireDate: nextTime
                                          interval: 0.0
                                            target: self
                                          selector: @selector( doRefresh )
                                          userInfo: nil repeats: NO ];

[[NSRunLoop currentRunLoop] addTimer: refreshTimer forMode: NSDefaultRunLoopMode];

当然，用类所需的方法替换“doRefresh”

尝试创建一次日历对象，并使allUnits为静态的效率。

添加一小时组件就可以了，不需要午夜测试(链接)

就像这样:

NSTimer *timer;

    timer = [NSTimer scheduledTimerWithTimeInterval: 0.5
                     target: self
                     selector: @selector(handleTimer:)
                     userInfo: nil
                     repeats: YES];

有几种使用计时器的方法:

1)定时定时器和使用选择器

NSTimer *t = [NSTimer scheduledTimerWithTimeInterval: 2.0
                      target: self
                      selector:@selector(onTick:)
                      userInfo: nil repeats:NO];

如果你将repeat设置为NO，计时器将在运行选择器之前等待2秒，之后它将停止; 如果重复:YES，计时器将立即启动，并将每2秒重复调用选择器; 要停止计时器，请调用计时器的-invalidate方法:[t invalidate];

作为旁注，与其使用不重复的计时器，并在指定的间隔后调用选择器，不如使用如下简单的语句:

[self performSelector:@selector(onTick:) withObject:nil afterDelay:2.0];

这将与上面的示例代码具有相同的效果;但如果你想每n次调用一次选择器，你可以使用重复的计时器:YES;

2)自动定时定时器

NSDate *d = [NSDate dateWithTimeIntervalSinceNow: 60.0];
NSTimer *t = [[NSTimer alloc] initWithFireDate: d
                              interval: 1
                              target: self
                              selector:@selector(onTick:)
                              userInfo:nil repeats:YES];

NSRunLoop *runner = [NSRunLoop currentRunLoop];
[runner addTimer:t forMode: NSDefaultRunLoopMode];
[t release];

这将创建一个计时器，该计时器将在您指定的自定义日期(在本例中为一分钟后)开始，并每一秒钟重复一次

3)计划外定时器&使用调用

NSMethodSignature *sgn = [self methodSignatureForSelector:@selector(onTick:)];
NSInvocation *inv = [NSInvocation invocationWithMethodSignature: sgn];
[inv setTarget: self];
[inv setSelector:@selector(onTick:)];

NSTimer *t = [NSTimer timerWithTimeInterval: 1.0
                      invocation:inv 
                      repeats:YES];

在那之后，你可以手动启动计时器，就像这样:

NSRunLoop *runner = [NSRunLoop currentRunLoop];
[runner addTimer: t forMode: NSDefaultRunLoopMode];

注意，onTick: method看起来是这样的:

-(void)onTick:(NSTimer *)timer {
   //do smth
}