在 UIScrollView 上显示大 UIView 的最佳方式是什么

What is the best way to show large UIView on UIScrollView?(在 UIScrollView 上显示大 UIView 的最佳方式是什么?)

问题描述

我有一个大的 UIView.它的大小可变.它可能大于 5000x5000 size.我使用 UIBezierPath 在其上绘制线条、圆圈.我还在上面添加了一些 view.这些 subview 中的每一个都包含 buttons、textview、labels 等.

I have an large UIView. Its variable size. It may be larger than 5000x5000 size. I draw lines, circles on it using UIBezierPath. Also I add some view's on it. Each of these subview's contains buttons, textview, labels, etc.

我把这个主视图放在 UIScrollView 上.UIScrollView 是 zoomable 并且必须非常清晰地显示内容(它不应该变得模糊).

I placed this main view on UIScrollView. UIScrollView is zoomable and have to show the contents very sharply (It should not get blurred).

目前，我绘制完整的 UIView 并添加到 UIScrollView.问题是，由于内存压力问题，它占用了太多的memory和崩溃.

Currently, I draw complete UIView and added on UIScrollView. The problem is that, Its taking too much memory and crashing because of Memory Pressure Issue.

我应该如何处理以实现高性能?

How should I handle this to achieve high performance?

推荐答案

继承UIView并在其中实现+layerClass方法:

Subclass UIView and implement the +layerClass method in it:

+layerClass
{
    return [CATiledLayer class];
}

这会导致您的视图由 CATiledLayer 而不是单个巨大的 CALayer 支持(在该大小下会消耗太多内存).

This causes your view to be backed by CATiledLayer instead of a single, huge CALayer (which would consume too much memory at that size).

然后，您只需在自定义视图类中实现 -(void)drawRect:(CGRect)rect 并在其中完成所有绘图.我最近在我的项目中必须这样做，该项目使用 UIScrollViews 滚动一个可以达到 10000 x 150000 的区域.

Then you just implement -(void)drawRect:(CGRect)rect in your custom view class and do all of your drawing in there. I had to do this recently in my project which uses UIScrollViews to scroll over an area that can be as big as 10000 x 150000.

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