iOS中簡單易懂秒殺倒計時／倒計時

iOS中簡單易懂秒殺倒計時／倒計時

範例程式碼簡單易懂：

#import @interface ViewController : UIViewController@property (weak, nonatomic) IBOutlet UILabel *dayLabel;@property (weak, nonatomic) IBOutlet UILabel *hourLabel;@property (weak, nonatomic) IBOutlet UILabel *minuteLabel;@property (weak, nonatomic) IBOutlet UILabel *secondLabel;@end

#import "ViewController.h"@interface ViewController (){     dispatch_source_t _timer;}@end@implementation ViewController/** *  擷取當天的年月日的字串 *  這裡測試用 *  @return 格式為年-月-日 */-(NSString *)getyyyymmdd{    NSDate *now = [NSDate date];    NSDateFormatter *formatDay = [[NSDateFormatter alloc] init];    formatDay.dateFormat = @"yyyy-MM-dd";    NSString *dayStr = [formatDay stringFromDate:now];        return dayStr;    }- (void)viewDidLoad {    [super viewDidLoad];    NSDateFormatter *dateFormatter=[[NSDateFormatter alloc] init];    [dateFormatter setDateFormat:@"yyyy-MM-dd"];        NSDate *endDate = [dateFormatter dateFromString:[self getyyyymmdd]];    NSDate *endDate_tomorrow = [[NSDate alloc] initWithTimeIntervalSinceReferenceDate:([endDate timeIntervalSinceReferenceDate] + 24*3600)];    NSDate *startDate = [NSDate date];    NSTimeInterval timeInterval =[endDate_tomorrow timeIntervalSinceDate:startDate];        if (_timer==nil) {        __block int timeout = timeInterval; //倒計時時間                if (timeout!=0) {            dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);            _timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0,queue);            dispatch_source_set_timer(_timer,dispatch_walltime(NULL, 0),1.0*NSEC_PER_SEC, 0); //每秒執行            dispatch_source_set_event_handler(_timer, ^{                if(timeout<=0){ //倒計時結束，關閉                    dispatch_source_cancel(_timer);                    _timer = nil;                    dispatch_async(dispatch_get_main_queue(), ^{                        self.dayLabel.text = @"";                        self.hourLabel.text = @"00";                        self.minuteLabel.text = @"00";                        self.secondLabel.text = @"00";                    });                }else{                    int days = (int)(timeout/(3600*24));                    if (days==0) {                        self.dayLabel.text = @"";                    }                    int hours = (int)((timeout-days*24*3600)/3600);                    int minute = (int)(timeout-days*24*3600-hours*3600)/60;                    int second = timeout-days*24*3600-hours*3600-minute*60;                    dispatch_async(dispatch_get_main_queue(), ^{                        if (days==0) {                            self.dayLabel.text = @"0天";                        }else{                            self.dayLabel.text = [NSString stringWithFormat:@"%d天",days];                        }                        if (hours<10) {                            self.hourLabel.text = [NSString stringWithFormat:@"0%d",hours];                        }else{                            self.hourLabel.text = [NSString stringWithFormat:@"%d",hours];                        }                        if (minute<10) {                            self.minuteLabel.text = [NSString stringWithFormat:@"0%d",minute];                        }else{                            self.minuteLabel.text = [NSString stringWithFormat:@"%d",minute];                        }                        if (second<10) {                            self.secondLabel.text = [NSString stringWithFormat:@"0%d",second];                        }else{                            self.secondLabel.text = [NSString stringWithFormat:@"%d",second];                        }                                            });                    timeout--;                }            });            dispatch_resume(_timer);        }    }}效果：