ios - 运行 NSTimer 一定次数

Question

是否可以像这样运行 NSTimer:

NSTimer *f = [[NSTimer alloc] initWithFireDate:[NSDate date]
                                      interval:.05
                                        target:self
                                      selector:@selector(checkForCollisions)
                                      userInfo:nil repeats:YES];

NSRunLoop *runner = [NSRunLoop currentRunLoop];
[runner addTimer:f forMode: NSDefaultRunLoopMode];
[f release];

但指定我希望它运行的次数？那么，如果我想让它只运行 2 秒(假设间隔为 .05)，我可以指定它运行 40 次吗？这可能吗？

Answer 1

你的ViewController.h

NSTimer *f;
NSInteger counter;

你的ViewController.m

- (void)setup {
    // initialization code
    counter = 0;
    f = [[NSTimer alloc] initWithFireDate:[NSDate date]
                                 interval:.05
                                   target:self
                                 selector:@selector(checkForCollisions)
                                 userInfo:nil repeats:YES];

    NSRunLoop *runner = [NSRunLoop currentRunLoop];
    [runner addTimer:f forMode: NSDefaultRunLoopMode];
}

- (void)checkForCollisions {
    // handle check

    counter++;
    if (counter >= 40) {
        [f invalidate];
        [f release];
    }
}