UIImageView startAnimating:你如何让它停止在系列的最后一张图片上？

- (void)startAnimatingWithTimer {
    NSArray *images = @[image1, image2, image3];
    NSInteger count = images.count;
    NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(timerFired:) userInfo:@{@"images": images} repeats:YES];
    _timer = timer;
}

- (void)timerFired:(NSTimer *)timer {
    NSArray *images = timer.userInfo[@"images"];
    static NSInteger index = 0;
    if (index == images.count) {
        index = 0;
    }
    UIImage *image = images[index];
    self.image = image;
    index++;
}

- (void)stopAnimating {
    [_timer invalidate];
    _timer = nil;
}

- (void)startAnimatingWithKeyframeAnimation {
    NSArray *images = @[image1, image2, image3];
    CAKeyframeAnimation *animation = [CAKeyframeAnimation animationWithKeyPath:@"contents"];
    animation.duration = 1.0;
    animation.values = images;
    animation.repeatCount = 1;
    animation.delegate = self;
    [self.layer addAnimation:animation forKey:@"imageAnimation"];
}

- (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag {
    if (flag) {
        [self.layer removeAnimationForKey:@"imageAnimation"];
        self.image = [anim.values lastObject];
    }
}

- (void)stopAnimating {
    [self.layer removeAnimationForKey:@"imageAnimation"];
}