首次触摸时，UIScrollView会跳转

Question

I have two UIScrollViews, one horizontal, one vertical, both two pages each (as in, the horizontal one is two pages wide, and the vertical one is two pages high). The horizontal scrollview is in the vertical one. I am trying to imitate Calcbot's design, where you can scroll left/right for buttons and up/down for history.

However, when the view loads, the horizontal scroll view is about 100 pixels higher than where it should be. Then, when I touch it and begin moving it a little, it jumps/skips down to the correct position and stays there. How do I have it appear correctly right from the start?

Here is my code for viewDidLoad:

-(void)viewDidLoad {
horizontalScrollView.pagingEnabled = YES;
verticalScrollView.pagingEnabled = YES;


horizontalScrollView.contentSize = CGSizeMake(horizontalScrollView.bounds.size.width * 2, horizontalScrollView.bounds.size.height); // 2 pages wide.
verticalScrollView.contentSize = CGSizeMake(verticalScrollView.bounds.size.width, verticalScrollView.bounds.size.height * 2);


horizontalScrollView.delegate = self;
verticalScrollView.delegate = self;




[verticalScrollView addSubview:horizontalScrollView];

[verticalScrollView setContentOffset:CGPointMake(0, 640)];

[self.view addSubview:verticalScrollView];

horizontalScrollView.frame = CGRectMake(0, 540, 320, 460);

}

Thanks.

Answer 1

当你设置了pagingEnabled = YES并且contentOffset设置为不在页面边界上的位置（由bounds.size.height分割）时，通常会跳过UIScrollView。

Answer 2

Just a quick thought because I am currently messing with UIScrollView too. You could try using -(void)viewWillAppear:(BOOL)animated . Eg I set my min and max scrolling in that method because it depends on the size of the content which, from what I read, isn't set until viewWillAppear.

Answer 3

Move this line

horizontalScrollView.frame = CGRectMake(0, 540, 320, 460);

In viewWillAppear instead of viewDidLoad , see if it works