我已经在第二次创建倒计时,比方说10秒,但我想让它更精确
到10.0并将其显示在标签上,它是如何做到的?提前致谢
这就是我现在所做的“第二次”倒计时
我的NSTimer
counterSecond = 10
NSTimer timer1 = [NSTimer scheduledTimerWithTimeInterval : 1
Target:self selector:@selector (countLabel) userInfo:nil repeats:YES];
-(void)countLabel:
counterSecond --;
self.timerLabel.text = [NSString stringWithFormat @"%d", counterSecond];
答案 0 :(得分:15)
我会使用开始日期/时间来跟踪倒计时。因为iOS可以延迟为其他任务触发计时器。
- (void)countdownUpdateMethod:(NSTimer*)theTimer {
// code is written so one can see everything that is happening
// I am sure, some people would combine a few of the lines together
NSDate *currentDate = [NSDate date];
NSTimeInterval elaspedTime = [currentDate timeIntervalSinceDate:startTime];
NSTimeInterval difference = countdownSeconds - elaspedTime;
if (difference <= 0) {
[theTimer invalidate]; // kill the timer
[startTime release]; // release the start time we don't need it anymore
difference = 0; // set to zero just in case iOS fired the timer late
// play a sound asynchronously if you like
}
// update the label with the remainding seconds
countdownLabel.text = [NSString stringWithFormat:@"Seconds: %.1f", difference];
}
- (IBAction)startCountdown {
countdownSeconds = 10; // Set this to whatever you want
startTime = [[NSDate date] retain];
// update the label
countdownLabel.text = [NSString stringWithFormat:@"Seconds: %.1f", countdownSeconds];
// create the timer, hold a reference to the timer if we want to cancel ahead of countdown
// in this example, I don't need it
[NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector (countdownUpdateMethod:) userInfo:nil repeats:YES];
// couple of points:
// 1. we have to invalidate the timer if we the view unloads before the end
// 2. also release the NSDate if don't reach the end
}
答案 1 :(得分:0)
counterSecond = 10
NSTimer timer1 = [NSTimer scheduledTimerWithTimeInterval : 0.1
Target:self selector:@selector (countLabel) userInfo:nil repeats:YES];
-(void)countLabel:
counterSecond - 0.1;
self.timerLabel.text = [NSString stringWithFormat @"%f", counterSecond];
这应该有效。