倒计时 ios（ios倒计时软件精确到秒）

示例代码简单易懂：

1 2 3 4 5 6 7 8 9 10 11 12 13 #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</uikit>

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 #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); } } } <span style="font-family: arial, verdana, sans-serif;">效果：</span>