label.layer.borderColor = .... 不工作（Xcode 4.3.2）
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label.layer.borderColor = .... not working (Xcode 4.3.2)
提问by tarheel
I am working in a class that is a subclass of UITableViewCell and have firstLabel and secondLabel properties declared in .h and being @synthesize in .m. When I go to format the UILabels programmatically, I try to set the border around the firstLabel. From the answer given in this question, I tried to do the same in my project.
我在一个类中工作，该类是 UITableViewCell 的子类，并且在 .h 中声明了 firstLabel 和 secondLabel 属性，在 .m 中是 @synthesize。当我以编程方式格式化 UILabels 时，我尝试在 firstLabel 周围设置边框。从给出的答案这个问题，我试图做同样的在我的项目。
firstLabel.layer.borderColor = [UIColor blackColor].CGColor;
The problem is that it won't recognize it, after I type firstLabel.layer. and hit 'esc' (to get the list of completions) Xcode comes up with nothing. What is the problem?
问题是在我输入 firstLabel.layer 后它不会识别它。并点击“esc”（以获取完成列表）Xcode 什么也没有出现。问题是什么？
Note: if I type
注意：如果我输入
firstLabel.textAlignment = UITextAlignmentCenter;
it works just fine and behaves as expected.
它工作得很好并且按预期运行。
回答by borrrden
You need to import the QuartzCore header. #import <QuartzCore/QuartzCore.h>
您需要导入 QuartzCore 标头。 #import <QuartzCore/QuartzCore.h>
(And don't forget to add the QuartzCore library as well or you will get a linker error when you try to build).
（并且不要忘记添加 QuartzCore 库，否则在尝试构建时会出现链接器错误）。
回答by Dzy
Did you set border width?
你设置边框宽度了吗？
Like this:
像这样：
[firstLabel.layer setBorderWidth:1.0f];
