具有背景图案的大型UIScrollView失败 [英] Large UIScrollView with background pattern fails

问题描述

我有一个UIScrollView，它具有非常大的内容视图，它是一个书架，上面有大约1000个项目，当滚动视图的内容高度超过16000px时，它显示黑色背景，并且所有图形重叠/融合在一起.

这是示例代码

 -(void)viewDidLoad {[super viewDidLoad];//无效int sizeForContent = 20000;//可以工作//sizeForContent = 10000;UIScrollView * scroll = [[UIScrollView分配] initWithFrame:CGRectMake(0，0，self.view.frame.size.width，self.view.frame.size.height)];UIView * subView = [[UIView分配] initWithFrame:CGRectMake(0，0，self.view.frame.size.width，sizeForContent)];subView.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"wood.jpg"]];[scroll addSubview:subView];[subView版本]；scroll.contentSize = CGSizeMake(self.view.frame.size.width，sizeForContent);[self.view addSubview:scroll];[滚动发布]；} 

有人知道为什么会这样吗?我认为这与内存限制有关，但似乎并没有占用太多内存.

我知道我可以直接设置scrollview背景颜色，而无需添加子视图并设置其背景，但是我需要将scrollview背景保留为颜色.

如果想查看，可以从 http://cl.ly/2i3F3q0G1j3q433n0f1E 中获得基本的xcode项目问题.

任何帮助或解释都将不胜感激.

解决方案

我通过创建具有图案背景的视图并将滚动视图添加为具有 [UIColor clearColor] 背景的子视图来解决此问题.

I have a UIScrollView with a very large content view, it's a bookshelf with around 1000 items on it, when the scroll views content becomes more than around 16000px high it shows a black background and all graphics overlap/blend together.

Here is the sample code

- (void)viewDidLoad {
    [super viewDidLoad];

    // Doesn't work
    int sizeForContent = 20000;

    // Does Work
    //sizeForContent = 10000;


    UIScrollView *scroll = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];  

    UIView *subView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, sizeForContent)];
    subView.backgroundColor = [UIColor colorWithPatternImage: [UIImage imageNamed: @"wood.jpg"]];
    [scroll addSubview:subView];
    [subView release];

    scroll.contentSize = CGSizeMake(self.view.frame.size.width, sizeForContent);
    [self.view addSubview:scroll]; 

    [scroll release];

}

Does anyone know why this happens? I assume it is something to do with memory limits but it doesn't seem to be using much memory.

I know I could set the scrollview background color directly instead of adding a subview and setting the background of that but I need to leave the scrollview background as a color.

You can get the basic xcode project from http://cl.ly/2i3F3q0G1j3q433n0f1E if you want to see the issue.

Any help or explanations greatly appreciated.

解决方案

I solved it by creating view with pattern background, and adding scroll view as subview with [UIColor clearColor] background.

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