问题描述

我想制作一个 UIButtonTypeCustom 类型的 UIButton(用于形状).我想使用 button.titleLabel 分配标题，因为我需要指定字体.下面的代码看起来应该可以工作，但没有——没有显示标签，句号.

I want to make a UIButton with type UIButtonTypeCustom (for the shape). I want to assign the title using button.titleLabel because I need to specify the font. The following code looks like it should work, but doesn't -- no label shows up, period.

UIImage *editButtonImage = [UIImage imageNamed: @"editButton.png"];
float width = editButtonImage.size.width;
float height = editButtonImage.size.height;

UIButton *editButton = [UIButton buttonWithType: UIButtonTypeCustom];
editButton.frame = CGRectMake(0, 0, width, height);
[editButton setBackgroundImage: editButtonImage forState: UIControlStateNormal];
editButton.adjustsImageWhenHighlighted = YES;
editButton.titleLabel.text = @"Edit";
editButton.titleLabel.textColor = [UIColor whiteColor];
editButton.titleLabel.textAlignment = UITextAlignmentCenter;
editButton.titleLabel.font = [UIFont fontWithName: @"Helvetica" size: 14];
[self.view addSubview: editButton];

每个人总是说要使用 setTitle:forState: 但这会给你一种我不喜欢的字体.titleLabel 方法没有被弃用——它应该可以工作.

Everyone always says to use setTitle:forState: but that gives you a font I don't like. The titleLabel method is NOT deprecated -- it should work.

我之前遇到过几次，并且总是解决它，但我真的很想弄清楚.有什么想法吗?

I have run into this several times before and always just worked around it, but I'd really like to figure it out. Any ideas?

推荐答案

像这样设置 titleLabel 的 text 属性没有任何效果.相反，在按钮上调用 -setTitle:forState::

Setting the titleLabel's text property like that has no effect. Instead, call -setTitle:forState: on the button:

[editButton setTitle:@"Edit" forState:UIControlStateNormal]

这是因为按钮可以为不同的状态有不同的标题(例如，UIControlStateDisabled、UIControlStateHighlighted).如果您没有明确指定其他状态，则为 UIControlStateNormal 控件状态设置属性将应用于所有状态.

The reason for this is because the button can have different titles for different states (e.g., UIControlStateDisabled, UIControlStateHighlighted). Setting a property for the UIControlStateNormal control state will apply to all the states if you don't specify the others explicitly.

根据 UIButton 的文档:

此类提供设置按钮的标题、图像和其他外观属性的方法.通过使用这些访问器，您可以为每个按钮状态指定不同的外观.

This class provides methods for setting the title, image, and other appearance properties of a button. By using these accessors, you can specify a different appearance for each button state.

您可以根据状态自定义标签的颜色和阴影颜色.分别参见 -setTitleColor:forState 和 -setTitleShadowColor:forState.titleLabel 上的其余属性，例如 textAlignment 和 font，应该按照您现在设置的方式工作，并且应该应用于所有控件州.

You can customize label's color and shadow color based on the state. See -setTitleColor:forState and -setTitleShadowColor:forState, respectively. The rest of the properties on titleLabel, such as textAlignment and font, should work as you have them set now and should apply to all the control states.

具体而言，请参阅 UIButton 的 titleLabel 属性的文档:https://developer.apple.com/documentation/uikit/uibutton/1623992-titlelabel

Specifically, see the documentation for UIButton's titleLabel property: https://developer.apple.com/documentation/uikit/uibutton/1623992-titlelabel

titleLabel 本身是只读的，但这并不意味着您不能更改其自身属性的值，例如字体、换行模式等.

titleLabel itself is read-only, but that doesn't mean you can't change the values of its own properties, such as font, line break mode, etc.

这篇关于iOS:UIButton titleLabel——它有什么作用吗?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持编程学习网！