ios 倒数计时器ios教程？
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CountDown Timer ios tutorial?
提问by zeeshan shaikh
I'm making an application where the exams is going on, so when exam start the, time should start with that. For example 30 minutes and it should reduce like 29:59.
我正在申请进行考试，所以当考试开始时，时间应该从那个开始。例如 30 分钟，它应该像 29:59 一样减少。
How can I implement this?
我该如何实施？
Can anyone please give me a sample example or a easy step by step tutorial that i can follow?
任何人都可以给我一个示例示例或我可以遵循的简单的分步教程吗？
回答by Adrian P
This code is used to create a countdown timer.
此代码用于创建倒数计时器。
Code for .h file.
.h 文件的代码。
@interface UIMyContoller : UIViewController {
NSTimer *timer;
IBOutlet UILabel *myCounterLabel;
}
@property (nonatomic, retain) UILabel *myCounterLabel;
-(void)updateCounter:(NSTimer *)theTimer;
-(void)countdownTimer;
@end
Code for .m file.
.m 文件的代码。
@implementation UIMyController
@synthesize myCounterLabel;
int hours, minutes, seconds;
int secondsLeft;
- (void)viewDidLoad {
[super viewDidLoad];
secondsLeft = 16925;
[self countdownTimer];
}
- (void)updateCounter:(NSTimer *)theTimer {
if(secondsLeft > 0 ) {
secondsLeft -- ;
hours = secondsLeft / 3600;
minutes = (secondsLeft % 3600) / 60;
seconds = (secondsLeft %3600) % 60;
myCounterLabel.text = [NSString stringWithFormat:@"%02d:%02d:%02d", hours, minutes, seconds];
} else {
secondsLeft = 16925;
}
}
-(void)countdownTimer {
secondsLeft = hours = minutes = seconds = 0;
if([timer isValid]) {
[timer release];
}
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
timer = [NSTimer scheduledTimerWithTimeInterval:1.0f target:self selector:@selector(updateCounter:) userInfo:nil repeats:YES];
[pool release];
}
Hope this helps you out.
希望这可以帮助你。
