如何将 Nsstring 转换为 NSDate？

Question

我想将 nsstring 转换为 nsdate 我有字符串有这个值

08:00:00

我想转换它所以我写了这段代码

NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"HH:mm:ss"];  
NSDate *startDate = [formatter dateFromString:_startTime];
NSLog(@"%@",startDate);

_startTime 有这个值 = 08:00:00

但是在我显示它之后的开始日期，它有这个值

2000-01-01 06:00:00 +0000

更新我写的这段代码

 NSString *dateString = _startTime;
NSDateFormatter *formatter= [[NSDateFormatter alloc] init];
// this is imporant - we set our input date format to match our input string
// if format doesn't match you'll get nil from your string, so be careful
[formatter setDateFormat:@"HH:mm:ss"];

NSDate *startDate = [[NSDate alloc] init];
// voila!
startDate = [formatter dateFromString:dateString];

NSLog(@"%@",startDate);

我希望输出为 08:00:00

Answer 1

你不能没有日期的 NSDate！如果您想从 NSDate 访问时间，则需要使用 NSDateComponents（或 NSTimeInterval）。

使用 NSDateComponents 从 NSDate 访问时间：

NSString *startTime = @"08:00:00";
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"HH:mm:ss"];
NSDate *startDate = [formatter dateFromString:startTime];

NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *components = [calendar components:(NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond) fromDate:startDate];
NSLog(@"%d:%d:%d", [components hour], [components minute], [components second]);

我不明白更改字符串的目的是什么 _startTime，你想比较日期吗？

编辑：

NSString *startTime = @"08:00:00";
NSString *endTime = @"23:00:00";

NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"HH:mm:ss"];
NSDate *startDate = [formatter dateFromString:startTime];
NSDate *endDate = [formatter dateFromString:endTime];

NSTimeInterval difference = [endDate timeIntervalSinceDate:startDate];

NSInteger temp = difference;

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

for (int i = 0; (i < difference && [newDate compare:startDate] == NSOrderedDescending); ++i)
{

    newDate = [startDate dateByAddingTimeInterval:(temp - i*60*10)];

    NSLog(@"%@",newDate);

}

运行这个并使用 NSDateComponents 记录你想要的！

Answer 2

使用这个代码我认为这个对你有帮助..

NSString *dateStr = @"08:00:00";
NSDateFormatter *datFormatter = [[NSDateFormatter alloc] init];
[datFormatter setDateFormat:@"HH:mm:ss"];
NSDate* mydate = [datFormatter dateFromString:dateStr];
NSLog(@"date: %@", [datFormatter stringFromDate:mydate]);

我想这就是你真正想要的...

如何将 Nsstring 转换为 NSDate？

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