NStimer在iOS中无法正常工作

Question

我正在使用以下代码显示时间...我在viewController中有滚动视图...这里我显示的时间从00:00.00开始(mm:ss:SS)(分钟:秒:毫秒)并且目标是递增毫秒,秒基于毫秒,基于秒的分钟...但我想显示从75:00.00(mm:ss:SS)开始的时间,我想将毫秒,秒和分钟减少到00:00.00(mm:ss) .SS)......我怎么能......？

我在以下链接中已经在SO中询问过这个问题.NSTimer以秒/毫秒减少时间

我按照那段代码时间不计算(在后台也是)当我拖动并按住滚动视图而不释放鼠标点击...帮我修改下面的代码...

enter code here
@interface ViewController : UIViewController
{
    IBOutlet UILabel *time;
    NSTimer *stopWatchTimer;
    NSDate *startDate;
    NSTimeInterval secondsAlreadyRun;
}

- (void)reset:(id)sender;
- (void)onStartPressed:(id)sender; 
- (void)onStopPressed:(id)sender;


enter code here
-(void)showActivity:(NSTimer *)tim 
{
    NSDate *currentDate = [NSDate date];

    NSTimeInterval timeInterval = [currentDate timeIntervalSinceDate:startDate];
    // Add the saved interval
    timeInterval += secondsAlreadyRun;
    NSDate *timerDate = [NSDate dateWithTimeIntervalSince1970:timeInterval];
    static NSDateFormatter * dateFormatter = nil;
    if( !dateFormatter ){
        dateFormatter = [[NSDateFormatter alloc] init];
        [dateFormatter setDateFormat:@"mm:ss.SS"];
        [dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0.0]];
    }
    NSString *timeString=[dateFormatter stringFromDate:timerDate];
    time.text = timeString;

    //    [dateFormatter release];
}

- (void)onStartPressed:(id)sender 
{
    stopWatchTimer = [NSTimer scheduledTimerWithTimeInterval:1/10 
                                                      target:self 
                                                    selector:@selector(showActivity:) 
                                                    userInfo:nil 
                                                     repeats:YES];
    // Save the new start date every time
    startDate = [[NSDate alloc] init]; // equivalent to [[NSDate date] retain];
    [stopWatchTimer fire];
}

- (void)onStopPressed:(id)sender
{
    // _Increment_ secondsAlreadyRun to allow for multiple pauses and restarts
    secondsAlreadyRun += [[NSDate date] timeIntervalSinceDate:startDate];
    [stopWatchTimer invalidate];
    stopWatchTimer = nil;

    //    [startDate release];
    //    [self showActivity:stopWatchTimer];
}

Answer 1

您必须注册计时器才能在NSRunLoopCommonModes中运行

stopWatchTimer = [NSTimer scheduledTimerWithTimeInterval:1/10 
                                                  target:self 
                                                selector:@selector(showActivity:) 
                                                userInfo:nil 
                                                 repeats:YES];
[[NSRunLoop currentRunLoop] addTimer:stopWatchTimer forMode:NSRunLoopCommonModes]; 

Answer 2

定时器在某些运行循环模式下的运行循环中进行调度.它们只能在以其中一种模式运行运行循环时触发.这些+scheduledTimerWithTimeInterval:...方法将计时器安排在默认模式下.在操作滚动条时跟踪事件使用NSEventTrackingRunLoopMode.您需要在正确的模式下安排计时器.

您可以将其安排在NSRunLoopCommonModes哪个虚拟模式集上.运行循环永远不会在这种模式下运行,但它们以该集合的成员模式运行.默认模式并按NSEventTrackingRunLoopMode原样添加到该集合中NSModalPanelRunLoopMode.