UIScrollView定时器

Question

我有一个UIScrollView并且想要设置一个定时器，所以如果我滚动并且什么也不做，大约10秒钟将会调用一个工作方法，并且如果在这10秒之前滚动，定时器将会重置。我的代码不起作用。

// Global vars 
NSDate *startDate, *endDate; 

// myTimer (NSTimer) and timerIsValid(BOOL) are part of my viewController class 

- (BOOL)timerExpired 
{ 

    NSDate *dateNow=[NSDate date]; 

    if ([[dateNow laterDate:endDate] isEqual:endDate]) { 
     return YES; 
    } 
    else { 
     return NO; 
    } 
} 

// If i begin scrolling i want to stop the timer 
- (void)scrollViewWillBeginDragging:(UIScrollView *)myScrollView 
{ 
    // Check if the timer is alive and invalidate it 
    if ([self timerExpired] == NO) { 
     NSLog(@"TIMER STILL ALIVE...KILL IT"); 
     [myTimer invalidate]; 
     myTimer = nil; 
     timerIsValid = NO; 
    } 
    else { 
     NSLog(@"TIMER IS DEAD");   
     timerIsValid = YES; 
    } 
} 

// After 10 seconds if i didn't scroll, i want to some job 
- (void)scrollViewDidEndDecelerating:(UIScrollView *)myScrollView 
{ 
    if (endDate) { 
     [endDate release]; 
    } 
    startDate = [NSDate date]; 
    endDate = [[startDate addTimeInterval:10.0] retain]; 

    if (!myScrollView.dragging) 
    { 
     if (autoscrollTimer == nil) { 
      // Create a new timer 
      myTimer = [NSTimer scheduledTimerWithTimeInterval:10.0 
                   target:self 
                  selector:@selector(timerFireMethod:) 
                  userInfo:nil 
                   repeats:YES]; 
     } 
    } 
} 

- (void)timerFireMethod:(NSTimer*)theTimer 
{ 
    if (timerIsValid) { 
     // do nothing 
     NSLog(@"DO NOTHING"); 
    } 
    else { 
     NSLog(@"DO SOME JOB"); 
     [self doSomeJob]; 
     timerIsValid = YES; 
    } 

} 

Answer 1

NSTimer *_scrollTimer; // instance variable 


- (void)scrollViewWillBeginDragging:(UIScrollView *)myScrollView 
{ 
    [_scrollTimer invalidate] 
    _scrollTimer = nil; 
} 

- (void)scrollViewDidEndDecelerating:(UIScrollView *)myScrollView 
{ 
    assert(_scrollTimer == nil); 
    _scrollTimer = [NSTimer scheduledTimerWithTimeInterval:10 
                target:self 
                selector:@selector(timerFireMethod:) 
                userInfo:nil 
                repeats:NO]; 
} 

- (void)timerFireMethod:(NSTimer *)theTimer 
{ 
    _scrollTimer = nil; 
    NSLog(@"DO SOME JOB"); 
}