获取UIScrollView的当前位置 [英] Get current position of UIScrollView

问题描述

我来自Android，而IOS令我头疼.我需要像电影学分一样制作滚动菜单.我使用下面的代码:

I'm coming from Android and i'm getting a lot of headache in IOS. I need to make a scroll menu like a movie credits. I used the code below:

rol = scroll_view.contentOffset.y;
timer = [NSTimer scheduledTimerWithTimeInterval:.02 target:self selector:@selector(timer_rol) userInfo:nil repeats:YES];

-(void)timer_rol{
    [scroll_view setContentOffset:CGPointMake(0,rol) animated:YES];
rol++;
}

此代码可以正常工作，但是当用户进行向上或向下滚动时，视图返回到之前的位置(rol值).问题是，滚动后如何获得当前内容的位置

This code works fine, but when the user interact scrolling up or down, the view return to position before (value of rol). The question is, how can i get the current content position after scrolling

我已经尝试过这些代码，但是没有人起作用:

i already tried these codes, but no one works:

CGPoint point = [scroll_view contentOffset];
rol = r.y  +1;

-(void) handleGesture:(UIGestureRecognizer *) sender{}
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {}
-(void)scrollViewDidScroll:(UIScrollView *)scrollView {}

有人可以帮助我吗?

推荐答案

解决方案是:

//Update the value of rol
- (void)scrollViewDidScroll:(UIScrollView *)scrollView{
    rol_y = scroll_webView.contentOffset.y;
    rol_x = scroll_webView.contentOffset.x;
}

//Call the timer
timer = [NSTimer scheduledTimerWithTimeInterval:.25 target:self selector:@selector(timer_rol) userInfo:nil repeats:YES];

//Scroll the view (Works when i set animated:NO)
- (void)timer_rol{
    [scroll_webView setContentOffset:CGPointMake(rol_x, rol_y + 1) animated:NO];
}

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