这UIButton的调整大小以适应其titleLabel

问题描述

我有一个UIButton，我添加到我的视图控制器视图故事板。我加定心约束来放置它，并导致空间的限制，以限制它的宽度。在code我补充一下：

I have a UIButton that I add to my view controller view in a storyboard. I add centering constraints to position it and leading space constraints to limit its width. In code I add:

self.button.titleLabel.numberOfLines = 0;
self.button.titleLabel.lineBreakMode = NSLineBreakByWordWrapping;
[self.button setTitle:@"A real real real real real real real real long long name." forState:UIControlStateNormal];
self.button.backgroundColor = [UIColor redColor];
self.button.titleLabel.backgroundColor = [UIColor blueColor];

的结果如下所示：

The result is shown below:

我希望按钮的大小对其内容。我怎样才能做到这一点？

I want the button to size to its content. How can I do this?

我试过

[self.button sizeToFit];

和我试过内容拥抱和COM pression电阻自动布局约束优先设置为必需的。

and I've tried setting the content hugging and compression resistance autolayout constraints priorities to required.

我也尝试明确设置contentEdgeInsets和titleEdgeInsets到UIEdgeInsetsZero并调用invalidateIntrinsicContentsize。

I've also tried explicitly setting the contentEdgeInsets and titleEdgeInsets to UIEdgeInsetsZero and calling invalidateIntrinsicContentsize.

我也注意到，如果我放在标题字符串换行符，按钮似乎要调整大小以适应其内容。

I've also noticed that if I place newline characters in the title string, the button does seem to resize to fit its content.

我在X code 6和iOS 8的iphone模拟器6运行。

I'm running on Xcode 6 and iOS 8 on the iphone 6 simulator.

推荐答案

我已经得到这个工作，但你必须使用一个自定义按钮，而不是一个系统类型。将按钮宽度和高度的限制，并作出一个IBOutlet的高度约束（heightCon在我的code），因此您可以在code调整。

I've gotten this to work, but you have to use a custom button, not a system type. Give the button both width and height constraints, and make an IBOutlet to the height constraint (heightCon in my code) so you can adjust it in code.

- (void)viewDidLoad {
    [super viewDidLoad];
    self.button.titleLabel.numberOfLines = 0;
    self.button.titleLabel.lineBreakMode = NSLineBreakByWordWrapping;
    [self.button setTitle:@"A real real real real real real real real long long name." forState:UIControlStateNormal];
    [self.button addTarget:self action:@selector(doStuff:) forControlEvents:UIControlEventTouchUpInside];
    self.button.backgroundColor = [UIColor redColor];
    self.button.titleLabel.backgroundColor = [UIColor blueColor];
    [self.button layoutIfNeeded]; // need this to update the button's titleLabel's size
    self.heightCon.constant = self.button.titleLabel.frame.size.height;
}

修改后：

我发现，你也可以做到这一点更简单，并与系统按钮，如果你犯了一个子类，并使用此code，

I found that you can also do this more simply, and with a system button if you make a subclass, and use this code,

@implementation RDButton

-(CGSize)intrinsicContentSize {
    return CGSizeMake(self.frame.size.width, self.titleLabel.frame.size.height);
}

当您设置标题的覆盖intrinsicContentSize方法被调用。你不应该在这种情况下设置一个高度约束。

The overridden intrinsicContentSize method is called when you set the title. You shouldn't set a height constraint in this case.

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