Question

我有两次...一个直接取为字符串（@“21:00”），其他是当前时间。我想显示一个倒数计时器，显示从现在开始到21:00的剩余时间。

例如：如果当前时间是17:30，我使用的标签应显示“你还有3小时30分钟......”。感谢..

Answer 1

确定已完全修改了我的答案，并创建了问题的完整解决方案，并在github上提供了经过全面测试的示例代码。

享受：）

Answer 2

这样的事情应该这样做。这将为您提供以秒为单位的剩余时间。然后你只需要标准计时器的东西，如其他答案中所示。

//assumption: targetTime is after now
NSString *targetTime = @"21:00";

//split our time into components
NSArray *timeSplit = [targetTime componentsSeparatedByString:@":"];

NSUInteger hours =  [[timeSplit objectAtIndex:0] intValue];
NSUInteger minutes =  [[timeSplit objectAtIndex:1] intValue];

NSDate *now = [NSDate date];

//split now into year month day components
NSCalendar *currentCalendar = [NSCalendar currentCalendar];
NSDateComponents *dateComponents = [currentCalendar components:NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit fromDate:now];

//set our time components from above
[dateComponents setHour:hours];
[dateComponents setMinute:minutes];

NSDate *targetDate = [currentCalendar dateFromComponents:dateComponents];

//ensure target is after now
if ([targetDate timeIntervalSinceDate:now] < 0)
{
    NSDateComponents *day = [[NSDateComponents alloc] init];
    [day setDay:1];

    targetDate = [currentCalendar dateByAddingComponents:day toDate:targetDate options:0]; 
}

NSTimeInterval timeRemaining = [targetDate timeIntervalSinceDate:now];

Answer 3

您创建一个每秒触发的NSTimer：

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

当它触发时，您输入一个方法：

- (void)tickClock;

在那里，您将日期与当前日期[NSData currentDate]进行比较;

像

NSTimeInterval distanceBetweenDates = [currentDate timeIntervalSinceDate:yourDate];

其中distanceBetweenDates以秒为单位指定。

要从字符串创建日期，请相应地创建NSDate

NSInteger year = 2011;
NSInteger month = 8;
NSInteger day = 26;
NSInteger hour = 21;
NSInteger minute = 0;
NSInteger second = 0;    


 NSCalendar *calendar = [NSCalendar currentCalendar];
 NSDateComponents *components = [[NSDateComponents alloc] init];
 [components setYear:year];
 [components setMonth:month];
 [components setDay:day];
 [components setHour:hour];
 [components setMinute:minute];
 [components setSecond:second];
  NSDate *date = [calendar dateFromComponents:components];
 [components release];

在iPhone中倒数计时器

3 个答案: