iOS中 简单易懂的秒杀倒计时／倒计时

转自：http://blog.csdn.net/qq_31810357/article/details/50700292

示例代码简单易懂：


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[objc] view
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#import <UIKit/UIKit.h>  

  

@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  

[objc] view
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#import "ViewController.h"  

  

@interface ViewController ()  

{  

     dispatch_source_t _timer;  

}  

@end  

  

@implementation ViewController  

/** 

 *  获取当天的年月日的字符串 

 *  这里测试用 

 *  @return 格式为年-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; //倒计时时间  

          

        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); //每秒执行  

            dispatch_source_set_event_handler(_timer, ^{  

                if(timeout<=0){ //倒计时结束，关闭  

                    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);  

        }  

    }  

  

  

}  

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效果：



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Demo下载地址GitHub：https://github.com/XiaoHanGe/CountDown