UIScrollView分页需要手动Edge Inset修改才能正常工作

Question

我有一个包含三个启用了分页的uiviewcontrollers的uiscrollview。当内容插入为{0,0,0,0}时，结果如下：

但是当我修改scrollview的内容插图以使左边有-7时，这就修复了它：

我想弄清楚为什么-7是解决这个问题的神奇数字？ 这是SliderViewController的代码

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil event:(Event*)event
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        _event = event;
         conversationVC = [[ConversationViewController alloc] initWithNibName:@"ConversationViewController" bundle:[NSBundle mainBundle] event:_event];
        eventVC = [[EventControlViewController alloc] initWithNibName:@"EventControlViewController" bundle:[NSBundle mainBundle]];
        suggestionVC = [[SuggestionViewController alloc] initWithNibName:@"SuggestionViewController" bundle:[NSBundle mainBundle]];
        [self addChildViewController:conversationVC];
        [self addChildViewController:eventVC];
        [self addChildViewController:suggestionVC];
        // Custom initialization
    }
    return self;
}
- (void)layoutSubviews
{
    CGFloat curXLoc = 0;
    CGFloat yMax = 0;
    for(UIView *view in _scrollView.subviews)
    {
        CGRect frame = view.frame;
        frame.origin.x = curXLoc;
        view.frame = frame;
        curXLoc += view.frame.size.width;
        yMax = MAX(view.frame.size.height, yMax);
    }
    [_scrollView setContentSize:CGSizeMake(_scrollView.subviews.count * 320, yMax)];
}
- (void)viewDidLoad
{
    [super viewDidLoad];
    _scrollView.clipsToBounds = YES;
    _scrollView.indicatorStyle = UIScrollViewIndicatorStyleWhite;
    [_scrollView addSubview:conversationVC.view];
    [_scrollView addSubview:eventVC.view];
    [_scrollView addSubview:suggestionVC.view];
    [self layoutSubviews];
}

Answer 1

如果您从情节提要板启动视图控制器，只需打开尺寸检查器以检查根视图的框架矩形的x是否设置为0