Question

我有一个UIView，它是UIScrollView的子视图。

我这样做是为了设置viewDidLoad中的内容大小（我在此网站上找到的实用代码段）：

CGFloat scrollViewHeight = 0.0f;
for (UIView* view in self.scrollView.subviews)
{
    scrollViewHeight += view.frame.size.height;
}

[self.scrollView setContentSize:(CGSizeMake(320, scrollViewHeight))];

使用NSLog我确定内容大小高度大于滚动视图的高度。但是，它仍然不会滚动。（我只对垂直滚动感兴趣。）

在IB中启用了滚动，所以我缺少什么？

Answer 1

这也发生在我身上 - 似乎从nib文件加载视图时，在 viewDidLoad之后甚至在viewWillAppear之后发生了一些调整。调用堆栈显示正在执行该操作的resizeWithOldSuperviewSize

#0 0x0000f040 in -[ScrollView setContentSize:] at .../ScrollView.m:49 #1 0x00092863 in -[UIScrollView _resizeWithOldSuperviewSize:] () #2 0x0007357a in -[UIView(Geometry) resizeWithOldSuperviewSize:] () #3 0x00072178 in __46-[UIView(Geometry) resizeSubviewsWithOldSize:]_block_invoke_0 () #4 0x01ccb5a7 in __NSArrayChunkIterate () #5 0x01ca303f in __NSArrayEnumerate () #6 0x01ca2a16 in -[NSArray enumerateObjectsWithOptions:usingBlock:] () #7 0x0007210f in -[UIView(Geometry) resizeSubviewsWithOldSize:] () #8 0x0056d14c in -[UIView(AdditionalLayoutSupport) _is_layout] () #9 0x00076dfe in -[UIView(Hierarchy) layoutSubviews] () #10 0x0007e92d in -[UIView(CALayerDelegate) layoutSublayersOfLayer:] () #11 0x010fa6b0 in -[NSObject performSelector:withObject:] () #12 0x022a5fc0 in -[CALayer layoutSublayers] () #13 0x0229a33c in CA::Layer::layout_if_needed(CA::Transaction*) () #14 0x022a5eaf in -[CALayer layoutIfNeeded] () #15 0x0011d8cd in -[UIViewController window:setupWithInterfaceOrientation:] () #16 0x000661a6 in -[UIWindow _setRotatableClient:toOrientation:updateStatusBar:duration:force:isRotating:] () #17 0x00064cbf in -[UIWindow _setRotatableClient:toOrientation:updateStatusBar:duration:force:] () #18 0x00064bd9 in -[UIWindow _setRotatableViewOrientation:duration:force:] () #19 0x00063e34 in __57-[UIWindow _updateToInterfaceOrientation:duration:force:]_block_invoke_0 () #20 0x00063c6e in -[UIWindow _updateToInterfaceOrientation:duration:force:] () #21 0x00064a29 in -[UIWindow setAutorotates:forceUpdateInterfaceOrientation:] () #22 0x00067922 in -[UIWindow setDelegate:] () #23 0x00111fec in -[UIViewController _tryBecomeRootViewControllerInWindow:] () #24 0x0005ebc4 in -[UIWindow addRootViewControllerViewIfPossible] () #25 0x0005edbf in -[UIWindow _setHidden:forced:] () #26 0x0005ef55 in -[UIWindow _orderFrontWithoutMakingKey] () #27 0x00067f67 in -[UIWindow makeKeyAndVisible] () #28 0x0000379a in -[AppDelegate application:didFinishLaunchingWithOptions:] at .../AppDelegate.m:24

我没有找到合适的解决方案，除了稍后通过调用performSelector设置contentSize：withObject：afterDelay

-(void)viewDidLoad { [self performSelector:@selector(adjustScrollViewContentSize) withObject:nil afterDelay:0.1]; } -(void)adjustScrollViewContentSize { _scrollView.contentSize = CGSizeMake(4000, 4000); }

Answer 2

userInteractionEnabled属性是否等于TRUE？也许你的滚动视图的子视图正在窃取触摸？

Answer 3

我同意塞佩尔。其他东西必须偷你的触摸。您可以测试此购买添加UIScollViewDelegate到您的类，并添加下面的事件回调方法之一。如果当你触摸滚动视图时他们没有被调用，那么你就知道Sepehr是正确的。

(void)scrollViewDidScroll:(UIScrollView *)scrollView
(void)scrollViewWillBeginDragging:(UIScrollView *)scrollView

Answer 4

问题来自自动布局根据约束设置contentSize。由于我的视图很复杂且自动布局不符合任务，我通过覆盖 setContentView：并忽略自动布局零高度 setContentSize：消息来解决它。

@interface MyView : UIScrollView {}
@end

@implementation MyView
- (void)setContentSize:(CGSize)aSize {
    if (aSize.height > 0)
        [super setContentSize:aSize];
}
@end

Answer 5

作为ddenis建议使用performSelector：withObject：afterDelay的替代方法，您可以在viewDidLayoutSubviews中调用setContentSize：

- (void)viewDidLayoutSubviews {
    [super viewDidLayoutSubviews];
    //do stuff here to calculate the content width and height
    // ...
    //then set the content size accordingly
    [self.scrollView setContentSize:(CGSizeMake(contentWidth, contentHeight))];
}

即使我设置了内容大小，UIScrollView也不会滚动

5 个答案: