NIB 文件中的内存管理和 UIImageView

发布于 2024-10-21 23:43:41 字数 1095 浏览 3 评论 0原文

我创建了一个示例应用程序，其中我将基本的全屏 UIImageView 设置为背景。这个应用程序非常简单。全部只有 2 页。（我将在下面发布代码）。 NIB仅作为UIImageView。我尝试了 2 种不同的场景 -

释放 NIB 文件和图像是否存在问题。

我遇到过一些内存泄漏。

1) 示例 1 (BAD) - 我将图像直接加载到 NIB 中。当我推动视图时，内存增加了 5MB。当我（使用 NavigationController）将视图从顶部弹出时，内存仅减少了 1.5MB。 Dealloc 确实被调用了。我没有 IBOutlet。所以，对我来说，这要么是缓存，要么是将该图像保留在内存中的某个地方。

2) 示例 2（好）- 为 UIImage 视图设置一个 IBOutlet，然后将图像放入 UIImageview 中，如下所示（我知道我可以以编程方式创建 UIImageView，但我在这里测试内存而不是我的屏幕创建技能）。这本身就可以很好地清理。它从内存中删除图像，我可以在仪器中看到内存下降。

@interface Page3VC : UIViewController {
    UIImageView*backimage;
}
@property(retain, nonatomic) IBOutlet UIImageView*backimage;
end

-(void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];

    backimage.image = [self getImage:@"hipHome.png"];
}
-(void)viewDidDisappear:(BOOL)animated {
    backimage.image = nil;

    [super viewDidDisappear:animated];
}

-(UIImage*)getImage:(NSString*)imageName{
    //return [UIImage imageNamed:imageName];
    return [UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:imageName ofType:nil]];
}

原文

I created a sample application that where I have a basic fullscreensize UIImageView set as the background. This app is very simple. All it is is 2 pages. (I will post the code below). The NIB only as UIImageView. I have tried 2 different scenarios -

Is there a problem with releasing NIB files and images.

I have been experiencing some memory leaks.

1) Example 1 (BAD)- I load the image directly in to the NIB. When I push the view, memory goes up by 5MB. When I pop (using NavigationController) the View off of the top, memory only goes down by a 1.5MB. Dealloc is indeed called. I have no IBOutlets. So, to me this is either caching or retaining this image in memory somewhere.

2) Example 2 (GOOD)- Set an IBOutlet for the UIImage view and I put the image in the UIImageview as shown below(I know I could create the UIImageView programmatically, but I am testing memory here not my screen creation skills). This cleans up nicely after itself. It removes the image from memory and I can see in Instruments that memory goes down.

@interface Page3VC : UIViewController {
    UIImageView*backimage;
}
@property(retain, nonatomic) IBOutlet UIImageView*backimage;
end

-(void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];

    backimage.image = [self getImage:@"hipHome.png"];
}
-(void)viewDidDisappear:(BOOL)animated {
    backimage.image = nil;

    [super viewDidDisappear:animated];
}

-(UIImage*)getImage:(NSString*)imageName{
    //return [UIImage imageNamed:imageName];
    return [UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:imageName ofType:nil]];
}

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