NSDate(NSCalendar,NSDateComponents,NSDateFormatter)
-1 NSString 转成 NSDate
NSString *time = @"2014-05-18 09:24:40"; NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; dateFormatter.dateFormat = @"yyyy-MM-dd HH:mm:ss"; NSDate *date = [dateFormatter dateFromString:time]; NSLog(@"%@",date);
-2 获取本地时间 (将格林威治时间转换成本地时间)
NSDate *date = [NSDate date]; NSTimeZone *zone = [NSTimeZone systemTimeZone]; NSInteger interval = [zone secondsFromGMTForDate:date]; NSDate *localeDate = [date dateByAddingTimeInterval:interval]; NSLog(@"%@",localeDate);
-3 将 NSDate 转成 NSString
NSDate *date = [NSDate date]; NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; dateFormatter.dateFormat = @"yyyy-MM-dd HH:mm:ss Z";//"Z"表示时区 NSString *currentDate = [dateFormatter stringFromDate:date]; NSLog(@"%@",currentDate);
使用 NSDateFormatter 会自动将时间转换成本地时间输出
-4 使用 NSCalendar 和 NSDateComponents 获取时间要素
NSDate *date = [NSDate date]; NSCalendar *calendar = [NSCalendar currentCalendar]; int unit = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond; NSDateComponents *dateComponents = [calendar components:unit fromDate:date]; NSLog(@"现在时间是%li年%li月%li天%li小时%li分钟%li秒", dateComponents.year, dateComponents.month, dateComponents.day, dateComponents.hour, dateComponents.minute, dateComponents.second);
-5 比较两个时间的时间差(这里以格林威治时间和本地时间做示例)
NSDate *date = [NSDate date]; NSTimeZone *zone = [NSTimeZone systemTimeZone]; NSInteger interval = [zone secondsFromGMTForDate:date]; NSDate *localeDate = [date dateByAddingTimeInterval:interval]; NSCalendar *calendar = [NSCalendar currentCalendar]; int unit = NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond; NSDateComponents *dateComponents = [calendar components:unit fromDate:date toDate:localeDate options:0]; NSLog(@"格林威治时间和本地时间相差%ld年%ld月%ld天%ld小时%ld分钟%ld秒", dateComponents.year, dateComponents.month, dateComponents.day, dateComponents.hour, dateComponents.minute, dateComponents.second);