在UIScrollView上显示大型UIView的最佳方法是什么？ [英] What is the best way to show large UIView on UIScrollView?

问题描述

我有一个很大的 UIView 。它的大小可变。它可能大于5000x5000 大小。我使用 UIBezierPath 在其上绘制线条，圆圈。我还在其上添加了一些视图。这些子视图中的每一个都包含按钮， textview ， 标签等。

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 。 UIScrollView 是 zoomable 并且必须非常清晰地显示内容（不应该模糊）。

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，它占用了太多内存和崩溃。

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

子类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 <支持/ code>而不是单个巨大的 CALayer （这会占用过多的内存）。

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

然后你只需在自定义视图类中实现 - （void）drawRect：（CGRect）rect 并全部执行你的画在那里。最近我必须在我的项目中执行此操作，该项目使用UIScrollViews滚动可以大到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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