我有一个滚动视图，它在加载时会自动向下滚动 web 视图，但不幸的是，由于如果用户触摸屏幕需要暂停动画，我无法将动画放在滚动视图中。
我在不使用块的情况下检测动画结束时遇到问题。这是我的代码，您可以看到我尝试使用的所有委托方法：
-(void)viewDidLoad{
[super viewDidLoad];
repeatCount = 0;
self.view.backgroundColor = [UIColor lightGrayColor];
self.webView.backgroundColor = [UIColor lightGrayColor];
self.scrollView.backgroundColor = [UIColor lightGrayColor];
self.scrollView.delegate=self;
NSString *htmlMessage =@"";
//Get text from local file and sent it to webview
NSString *filePath = [[NSBundle mainBundle] pathForResource:@"creditsMessage" ofType:@"txt"];
if (filePath) {
NSString *myText = [NSString stringWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil];
if (myText) {
htmlMessage = [htmlMessage stringByAppendingString:myText];
}
} else {
htmlMessage = _defaultErrorDocumentFileMissing;
}
//Load the HTML Message:
[self.webView loadHTMLString:htmlMessage baseURL:[NSURL fileURLWithPath:[[NSBundle mainBundle] bundlePath]]];
[self.webView sizeToFit];
}
-(void)viewDidAppear:(BOOL)animated{
[super viewDidAppear:YES];
setTimer = FALSE;
UITapGestureRecognizer *recognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(pauseLayer:)];
[self.scrollView addGestureRecognizer:recognizer];
recognizer.delegate = self;
[recognizer release];
//Start the scrolling
[self animateScroll];
}
- (void) animateScroll{
CGFloat scrollHeight = 710;
[UIScrollView beginAnimations:@"scrollAnimation" context:nil];
[UIScrollView setAnimationDuration:18.0f];
[self.scrollView setContentOffset:CGPointMake(0,scrollHeight)];
[UIScrollView commitAnimations];
[UIScrollView setAnimationDelegate:self];
[UIScrollView setAnimationDidStopSelector:@selector(animationDidStop:finished:context:)];
}
- (void)animationDidStop:(NSString*)animationID finished:(BOOL)finished context:(void *)context {
[self.scrollView setContentOffset:CGPointMake(0,0) animated:NO];
[self.scrollView setContentSize:CGSizeMake(320, 1500)];
self.scrollView.scrollEnabled = YES;
self.webView.scrollView.scrollEnabled = TRUE;
}
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer
shouldReceiveTouch:(UITouch *)touch {
if (self.scrollView.layer.timeOffset>0) {
[self resumeLayer:self.scrollView.layer]; //resume the animation on the subsequent touch
}
else {
//first we pause the animation
[self pauseLayer:self.scrollView.layer];
//after certain seconds we will start again the animation
double delayInSeconds = 2.0; //adjust this value
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
[self resumeLayer:self.scrollView.layer];
});
}
return YES;
}
-(void)pauseLayer:(CALayer*)layer {
CFTimeInterval pausedTime = [layer convertTime:CACurrentMediaTime() fromLayer:nil];
layer.speed = 0.0;
layer.timeOffset = pausedTime;
}
-(void)resumeLayer:(CALayer*)layer{
CFTimeInterval pausedTime = [layer timeOffset];
layer.speed = 1.0;
layer.timeOffset = 0.0;
layer.beginTime = 0.0;
CFTimeInterval timeSincePause = [layer convertTime:CACurrentMediaTime() fromLayer:nil] - pausedTime;
layer.beginTime = timeSincePause;
}
//Works on start of scroll
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
}
//None of the below work
-(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
}
-(void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{
}
-(void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView{
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
}