objective-c - 如何从 NSDate 倒计时并以小时和分钟显示

Question

我正在尝试从 NSDate 倒计时并以小时和分钟显示。像这样：1h:18min

目前我的日期正在更新为 UILabel 并倒计时，但显示如下：

这是我正在使用的代码。startTimer 方法和 updateLabel 方法

 - (void)startTimer {
        // Set the date you want to count from

    // convert date string to date then set to a label
    NSDateFormatter *dateStringParser = [[NSDateFormatter alloc] init];
    [dateStringParser setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss.000Z"];

    NSDate *date = [dateStringParser dateFromString:deadlineDate];

    NSDateFormatter *labelFormatter = [[NSDateFormatter alloc] init];
    [labelFormatter setDateFormat:@"HH-dd-MM-yyyy"];

    NSDate *countdownDate = [[NSDate alloc] init];

    countdownDate = date; 

    // Create a timer that fires every second repeatedly and save it in an ivar
    NSTimer *timer = [[NSTimer alloc] init];

    timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(updateLabel) userInfo:nil repeats:YES];

}

- (void)updateLabel {

    // convert date string to date then set to a label
    NSDateFormatter *dateStringParser = [[NSDateFormatter alloc] init];
    [dateStringParser setDateFormat:@"yyyy-MM-dd'T'HH:mm:ss.000Z"];

    NSDate *date = [dateStringParser dateFromString:deadlineDate];

    NSDateFormatter *labelFormatter = [[NSDateFormatter alloc] init];
    [labelFormatter setDateFormat:@"HH-dd-MM"];


    NSTimeInterval timeInterval = [date timeIntervalSinceNow]; ///< Assuming this is in the future for now.


    self.deadlineLbl.text = [NSString stringWithFormat:@"%f", timeInterval];
}

谢谢你的帮助

Answer 1

- (NSString *)stringFromTimeInterval:(NSTimeInterval)interval 
  {
    NSInteger ti = (NSInteger)interval;
    NSInteger seconds = ti % 60;
    NSInteger minutes = (ti / 60) % 60;
    NSInteger hours = (ti / 3600);
    return [NSString stringWithFormat:@"%02i:%02i:%02i", hours, minutes, seconds];
  }

Answer 2

由于您使用 NSTimeInterval ，您将获得时间间隔，即差异，以秒为单位，以小时和分钟显示它，您需要应用数学逻辑并转换它！你很多人需要几个循环来做到这一点。

试试这个

问候