子类放大UIScrollView没有委托方法 [英] Subclass a zooming UIScrollView without delegate methods

问题描述

我想实现一个 UIScrollView 子类来呈现一些自定义格式化的内容。我只是设置滚动视图的模型对象属性，它处理所有必需的布局和渲染以显示内容。

I want to implement a UIScrollView subclass to present some custom formatted content. I just set a model object property of the scroll view and it handles all the required layout and rendering to display the content.

这个工作正常，但现在我想包括缩放。根据文档，要支持缩放，你必须设置一个委托并实现 viewForZoomingInScrollView：方法。我想我可以设置委托到滚动视图本身，并在子类中实现该方法。但是，这样做会失去一个外部代理（如封装的UIViewController）的能力，可以通知滚动事件。

This works fine, but now I'd like to include zooming. According to the documentation, to support zooming you have to set a delegate and implement the viewForZoomingInScrollView: method. I guess I could set the delegate to the scroll view itself and implement that method in the subclass. But doing that I would lose the ability to have an external delegate (like an encapsulating UIViewController) that can be notified about scroll events.

假设文档是正确的，绝对没有（文档化）的方式实现缩放没有委托，我怎么能仍然保留有可能性有一个规则，无关的委托？

Assuming the documentation is right and there is absolutely no (documented) way to implement zooming without a delegate, how could I still retain the possibility of having a regular, unrelated delegate?

推荐答案

我滥用这个事实，我是一个子类（有意的：P）。所以你可以攻击它。真的很糟糕，对于提出这个解决方案，我感觉不太好。

I'd abuse the fact that I'm being a subclass (on purpose :P). So you can hack it. Really bad, and I should feel bad for proposing this solution.

@interface MyHackishScrollView: UIScrollView {
    id <UIScrollViewDelegate> ownDelegate;
}

@end

@implementation MyHackishScrollView

- (void)setDelegate:(id <UIScrollViewDelegate>)newDel
{
    ownDelegate = newDel;
    [super setDelegate:self];
}

- (UIView *)viewForScrollingInScrollView:(UIScrollView *)sv
{
    return whateverYouWant;
}

// and then implement all the delegate methods
// something like this:
- (void)scrollViewDidScroll:(UIScrollView *)sv
{
    [ownDelegate scrollViewDidScroll:self];
}

// etc.

@end

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