恢复功能在NSTime中无法正常工作

Question

我有一个NSTimer，可以用作秒表。 它计算时间并具有暂停功能，该功能可以正常工作，但该功能不能继续运行。 计时器似乎在计数，甚至是暂停，但没有更新标签，当我触摸该按钮时，该按钮会从您离开的地方继续计数，但并未停止。 我怎样才能解决这个问题？

这是我的计时器码：

- (void)viewDidLoad {
    [super viewDidLoad];
    [self setUp];
    self.isPaused = NO;

}

- (void) setUp {
    startDate = [NSDate date];
    _timer = [NSTimer scheduledTimerWithTimeInterval: 1.0/100.0 target: self selector: @selector(timerUpdating) userInfo: nil repeats: true];
}

-(void)timerUpdating {
    NSDate *currentDate = [NSDate date];
    NSTimeInterval timeInterval = [currentDate timeIntervalSinceDate:startDate];
    NSDate *timerDate  = [NSDate dateWithTimeIntervalSince1970:timeInterval];

    NSDateFormatter *dateFormater = [[NSDateFormatter alloc]init];
    [dateFormater setDateFormat:@"mm:ss"];
    [dateFormater setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0.0]];
    NSString *timeString = [dateFormater stringFromDate:timerDate];
    if (self.isPaused == NO){
        _timerLabel.text = timeString;
    }
}


- (IBAction)pauseAction:(id)sender {
    [self pauseTimer:self.timer];
}

- (IBAction)resumeAction:(id)sender {
    [self resumeTimer:self.timer];
}

-(void) pauseTimer:(NSTimer *)timer {
    self.isPaused = YES;
    self.pauseStart = [NSDate date];
    self.previousFireDate = [timer fireDate];
    [timer setFireDate:[NSDate distantFuture]];
}

-(void) resumeTimer:(NSTimer *)timer {
    self.isPaused =  NO;
    NSDate *currentDate = [NSDate date];
    NSTimeInterval pauseTime = [currentDate timeIntervalSinceDate:pauseStart];
    NSDate *neededFireDate = [NSDate dateWithTimeInterval:pauseTime sinceDate:previousFireDate];
    [timer setFireDate:neededFireDate];
    NSLog(@"Fire Date: %@", timer.fireDate);
}

Answer 1

在timerUpdating您可以设置NSTimeInterval timeInterval = [currentDate timeIntervalSinceDate:startDate]; 。 无论用户是否暂停计时器，都不会考虑到这一点。

要纠正此行为，您可以执行以下操作：

在.h中（设置成员变量）：

NSTimeInterval pausedTime;

以.m（已编辑3行）

- (void)viewDidLoad {
    [super viewDidLoad];
    [self setUp];
    self.isPaused = NO;
    pausedTime = 0;    //edit
}

- (void) setUp {
    startDate = [NSDate date];
    _timer = [NSTimer scheduledTimerWithTimeInterval: 1.0/100.0 target: self selector: @selector(timerUpdating) userInfo: nil repeats: true];
}

-(void)timerUpdating {
    NSDate *currentDate = [NSDate date];
    NSTimeInterval timeInterval = [currentDate timeIntervalSinceDate:startDate] - pauseTime;//edit
    NSDate *timerDate  = [NSDate dateWithTimeIntervalSince1970:timeInterval];

    NSDateFormatter *dateFormater = [[NSDateFormatter alloc]init];
    [dateFormater setDateFormat:@"mm:ss"];
    [dateFormater setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0.0]];
    NSString *timeString = [dateFormater stringFromDate:timerDate];
    if (self.isPaused == NO){
        _timerLabel.text = timeString;
    }
}


- (IBAction)pauseAction:(id)sender {
    [self pauseTimer:self.timer];
}

- (IBAction)resumeAction:(id)sender {
    [self resumeTimer:self.timer];
}

-(void) pauseTimer:(NSTimer *)timer {
    self.isPaused = YES;
    self.pauseStart = [NSDate date];
    self.previousFireDate = [timer fireDate];
    [timer setFireDate:[NSDate distantFuture]];
}

-(void) resumeTimer:(NSTimer *)timer {        
    self.isPaused =  NO;
    NSDate *currentDate = [NSDate date];
    NSTimeInterval pauseTime = [currentDate timeIntervalSinceDate:pauseStart];
    pausedTime += pauseTime;//edit
    NSDate *neededFireDate = [NSDate dateWithTimeInterval:pauseTime sinceDate:previousFireDate];
    [timer setFireDate:neededFireDate];
    NSLog(@"Fire Date: %@", timer.fireDate);
}