StretchableImageWithLeftCapWidth:topCapHeight在UIImageView子类的initWithCoder:中不起作用 [英] stretchableImageWithLeftCapWidth:topCapHeight doesn't work in initWithCoder: of UIImageView subclass

问题描述

我有一个名为ShadowView的UIImageView子类，该子类显示可以在任何情况下使用的阴影.ShadowViews将从笔尖加载.

I have a UIImageView subclass called ShadowView, which displays a shadow that can be used under anything. ShadowViews are to be loaded from a nib.

在initWithCoder:中，我有以下代码:

In initWithCoder:, I have the following code:

- (id)initWithCoder:(NSCoder *)decoder {
    self = [super initWithCoder:decoder];
    if (self != nil) {
        UIImage *shadowImage = [[UIImage imageNamed:@"drop_shadow_4_pix.png"] stretchableImageWithLeftCapWidth:4 topCapHeight:4];

        [self setContentMode:UIViewContentModeScaleToFill];
        [self setImage:shadowImage];
    }
    return self;
}

但是，当我运行该应用程序时，此图像不会出现.

When I run the app, though, this image does not appear.

但是如果我将其更改为

...
UIImage *shadowImage = [UIImage imageNamed:@"drop_shadow_4_pix.png"];
...

它工作正常，但被错误拉伸了.

it works fine, but it is stretched wrong.

关于为什么发生这种情况的任何想法吗?

Any ideas as to why this is happening?

编辑:当我以编程方式加载阴影视图时，使用initWithFrame:与initWithCoder:相似地实现，是相同的.

it is the same when I load the shadowview programmatically, with initWithFrame: implemented similarly to initWithCoder:.

另一个我想我已经解决了这个问题.我需要设置自动调整大小的蒙版.

Another I think I solved the problem. I needed to set the autoresizing masks.

推荐答案

shadowImage是否为空?

Is shadowImage nil?

UIImage *shadowImage = [[UIImage imageNamed:@"drop_shadow_4_pix.png"] stretchableImageWithLeftCapWidth:4 topCapHeight:4];

如果基本图像的宽度小于5像素或高度小于5像素，则该方法可能返回nil，因为它需要4个像素的上限和1个像素才能拉伸.

That method could return nil if the base image is less than 5 pixels wide or 5 pixels tall since it needs the 4 pixels for the caps + 1 pixel to stretch.

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