使用多层时无法释放未使用的CALayer内存 [英] Can't release unused CALayer memory when using multiple layers

问题描述

我在应用程序中使用多个CALayer，并以大型UIImage作为内容. 不幸的是，当我不需要图层或图像时，不会释放内存.

I am using multiple CALayer's in my application with large UIImage as contents. unfortunately, when I don't need the layer nor the image - the memory is not freed.

我用来创建图层的代码是:

the code I use to create the layer is:

UIImage *im = [UIImage imageNamed:@"image_1.jpg"];
CALayer * l = [CALayer layer];
[l setBounds:CGRectMake(0, 0, 1024, 768)];
[l setPosition:CGPointMake(512, 384)];
[l setAnchorPoint:CGPointMake(0.5, 0.5)];
[l setHidden:NO];
[l setContents:(id) im.CGImage];
[self.layer addSublayer:l]; // self is a subclass of UIView
[self.tmpArr addObject:l]; // self.tmpArr contains the layers I am using (one in this example)

我用来释放该层的代码是:

the code I use to release the layer and it's contents is :

CALayer * l = [self.tmpArr objectAtIndex:i];
[l removeFromSuperlayer];
[l setHidden:YES];
[l setContents:nil];
[self.tmpArr removeAllObjects];

当我使用仪器内存分析器时，我看到创建该层时实际内存增加了，但是释放该层时却没有减少. 由于使用的是ARC，因此无法使用release.我在这里做错了什么?

when I'm using the instruments memory profiler I see the real memory increasing when creating the layer but never decreasing when freeing there. I can't use release since I am using ARC. what do I do wrong here ?

谢谢.

推荐答案

UIImage的imageNamed:方法使用仅在内存不足时释放的静态缓存.

UIImage's imageNamed: method uses a static cache that is only released upon tight memory situations.

您的选择是:

1. 改为使用-[UIImage imageWithContentsOfFile:].
2. 忽略该问题.出现内存通知时，将清除缓存.

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