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.