IOS学习笔记之十七 (NSDate、NSDateFormatter、NSCalendar、NSDateComponents、NSTimer)

[NSDate date];

//NSDate转NSString
stringFromDate:dt
//NSString转NSDate
dateFromString

+ (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;

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转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时mm分"];
        NSLog(@"%@", [df stringFromDate:dt]);
        //NSString转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(@"现在是%ld年", comp.year);
        NSLog(@"现在是%ld月", comp.month);
        NSLog(@"现在是%ld日", comp.day);
        NSLog(@"现在是%ld时", comp.hour);
        NSLog(@"现在是%ld分", comp.minute);
        NSLog(@"现在是%ld秒", comp.second);
        NSLog(@"现在是星期%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]));
    }
}

@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