当我开始进行测验时,计时器开始倒计时“4 ... 3 ... 2 ... 1 ...”。 我想在第一个测验问题中添加这个倒计时。倒计时后显示第一个问题。
任何人都可以帮助我
我试图这样做,但我没有获得倒计时的格式。
NSTimer *timer_total = [NSTimer scheduledTimerWithTimeInterval:1.0/10.0 target:self selector:@selector(updateTimer) userInfo:nil repeats:YES];
- (void)updateTimer
{
NSDate *currentDate = [NSDate date];
NSTimeInterval timeInterval = [currentDate timeIntervalSinceDate:startDate_total];
NSDate *timerDate = [NSDate dateWithTimeIntervalSince1970:timeInterval];
self.df_total = [[NSDateFormatter alloc] init];
[self.df_total setDateFormat:@"mm:ss"];
[self.df_total setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0.0]];
NSString *timeString=[self.df_total stringFromDate:timerDate];
self.lbl_total_Timer.text = timeString;
}
答案 0 :(得分:0)
你可以这样做
int currentTime;
- (IBAction)start{
currentTime = 5;
lbl=[[UILabel alloc]init];
//creates and fires timer every second
myTimer = [[NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(showTime) userInfo:nil repeats:YES]retain];
}
-(void)showTime{
if(currentTime==0)
{
[myTimer invalidate];
myTimer = nil;
}
else{
currentTime--;
lbl.text = [NSString stringWithFormat:@"%.2d", currentTime];
}
NSLog(@"my lable == %@",lbl.text);
}
- (void)viewWillAppear:(BOOL)animated
{
[self start];
[super viewWillAppear:YES];
}