IOS學習筆記之十七 (NSDate、NSDateFormatter、NSCalendar、NSDateComponents、NSTimer)

1、NSDate

時間與日期的初始化,主要有

[NSDate date];      

2、NSDateFormatter

主要用于NSString和Date之間互相轉化

//NSDate轉NSString
 
stringFromDate:dt
 
//NSString轉NSDate
 
dateFromString      

3、NSCalendar和NSDateComponents

Date列印出具體時間的年月日和把年月日轉化為Date

4、NSTimer

定時器

+ (NSTimer *)timerWithTimeInterval:(NSTimeInterval)ti invocation:(NSInvocation *)invocation repeats:(BOOL)yesOrNo;
+ (NSTimer *)scheduledTimerWithTimeInterval:(NSTimeInterval)ti invocation:(NSInvocation *)invocation repeats:(BOOL)yesOrNo;
 
+ (NSTimer *)timerWithTimeInterval:(NSTimeInterval)ti target:(id)aTarget selector:(SEL)aSelector userInfo:(nullable id)userInfo repeats:(BOOL)yesOrNo;
+ (NSTimer *)scheduledTimerWithTimeInterval:(NSTimeInterval)ti target:(id)aTarget selector:(SEL)aSelector userInfo:(nullable id)userInfo repeats:(BOOL)yesOrNo;
       

5、測試Demo

main.m檔案

int main(int argc, char * argv[]) {
    @autoreleasepool {
        //NSDate常用方法
        NSDate *date = [NSDate date];
        NSLog(@"%@", date);
        NSDate *date1 = [[NSDate alloc] initWithTimeIntervalSinceNow:3600 * 24];
        NSLog(@"date1 is %@", date1);
        NSDate *date2 = [[NSDate alloc] initWithTimeIntervalSinceNow:-3 * 3600 * 24];
        NSLog(@"date1 is %@", date2);
        NSLocale *cn = [NSLocale currentLocale];
        NSLog(@"%@", [date1 descriptionWithLocale:cn]);
        NSLog(@"%@", [date1 earlierDate:date2]);
        
        //NSDate轉NSString
        NSDate *dt = [NSDate dateWithTimeIntervalSince1970:3600 * 24 * 366 * 20];
        NSDate *dt1 = [NSDate dateWithTimeIntervalSince1970:0];
        NSLog(@"%@", dt1);
        NSDateFormatter *df = [[NSDateFormatter alloc] init];
        [df setDateFormat:@"公元yyyy年MM月DD日 HH時mm分"];
        NSLog(@"%@", [df stringFromDate:dt]);
        //NSString轉NSDate
        
        NSString *str = @"2018-03-02";
        NSDateFormatter *df1 = [[NSDateFormatter alloc] init];
        [df1 setDateFormat:@"yyyy-MM-dd"];
        NSLog(@"%@", [df1 dateFromString:str]);
        
        //NSCalendar和NSDateComponents使用
        NSCalendar *car = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
        NSDate *date3 = [NSDate date];
        unsigned unit = NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit | NSWeekdayCalendarUnit;
        
        NSDateComponents *comp = [car components:unit fromDate:date3];
        NSLog(@"現在是%ld年", comp.year);
        NSLog(@"現在是%ld月", comp.month);
        NSLog(@"現在是%ld日", comp.day);
        NSLog(@"現在是%ld時", comp.hour);
        NSLog(@"現在是%ld分", comp.minute);
        NSLog(@"現在是%ld秒", comp.second);
        NSLog(@"現在是星期%ld", comp.weekday);
        
        NSDateComponents *comp1 = [[NSDateComponents alloc] init];
        comp1.year = 2015;
        comp1.month = 4;
        comp1.day = 5;
        comp1.hour = 18;
        comp1.minute = 34;
        NSDate *date4 = [car dateFromComponents:comp1];
        NSLog(@"date is %@:", date4);
        return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
    }
}      

ViewControl.m檔案(這裡實作的定時器)

@implementation ViewController
 
- (void)viewDidLoad {
    [super viewDidLoad];
//    Control *control = [Control new];
//    control.delegate = self;
//    [control willShowAlert];
    NSTimer* timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(Timered:) userInfo:nil repeats:YES];
}
 
- (void)Timered:(NSTimer*)timer {
    NSLog(@"hello chenyu");
}
@end      

6、運作的結果

2018-07-12 23:03:31.634870+0800 cyTest[37918:6787840] hello chenyu
2018-07-12 23:03:32.634915+0800 cyTest[37918:6787840] hello chenyu
2018-07-12 23:03:33.634881+0800 cyTest[37918:6787840] hello chenyu
2018-07-12 23:03:34.634938+0800 cyTest[37918:6787840] hello chenyu
2018-07-12 23:03:35.634998+0800 cyTest[37918:6787840] hello chenyu
2018-07-12 23:03:36.635095+0800 cyTest[37918:6787840] hello chenyu
2018-07-12 23:03:37.635086+0800 cyTest[37918:6787840] hello chenyu
 
2018-07-12 23:14:23.789640+0800 cyTest[38218:6796894] Thu Jul 12 23:14:23 2018
2018-07-12 23:14:23.790844+0800 cyTest[38218:6796894] date1 is Fri Jul 13 23:14:23 2018
2018-07-12 23:14:23.791492+0800 cyTest[38218:6796894] date1 is Mon Jul  9 23:14:23 2018
2018-07-12 23:14:23.804598+0800 cyTest[38218:6796894] Friday, July 13, 2018 at 11:14:23 PM China Standard Time
2018-07-12 23:14:23.804853+0800 cyTest[38218:6796894] Mon Jul  9 23:14:23 2018
2018-07-12 23:14:23.805346+0800 cyTest[38218:6796894] Thu Jan  1 08:00:00 1970
2018-07-12 23:14:23.805927+0800 cyTest[38218:6796894] 公元1990年01月16日 08時00分
2018-07-12 23:14:23.808330+0800 cyTest[38218:6796894] Fri Mar  2 00:00:00 2018
2018-07-12 23:14:23.808982+0800 cyTest[38218:6796894] 現在是2018年
2018-07-12 23:14:23.809150+0800 cyTest[38218:6796894] 現在是7月
2018-07-12 23:14:23.809354+0800 cyTest[38218:6796894] 現在是12日
2018-07-12 23:14:23.809558+0800 cyTest[38218:6796894] 現在是23時
2018-07-12 23:14:23.809684+0800 cyTest[38218:6796894] 現在是14分
2018-07-12 23:14:23.809834+0800 cyTest[38218:6796894] 現在是23秒
2018-07-12 23:14:23.810407+0800 cyTest[38218:6796894] 現在是星期5
2018-07-12 23:14:23.811211+0800 cyTest[38218:6796894] date is Sun Apr  5 18:34:00 2015:
2018-07-12 23:14:27.764633+0800 cyTest[38218:6796894] hello chenyu
2018-07-12 23:14:28.764758+0800 cyTest[38218:6796894] hello chenyu
2018-07-12 23:14:29.765776+0800 cyTest[38218:6796894] hello chenyu
2018-07-12 23:14:30.765792+0800 cyTest[38218:6796894] hello chenyu
2018-07-12 23:14:31.765426+0800 cyTest[38218:6796894] hello chenyu