iOS：UIButton titleLabel - 它有什么用呢？ [英] iOS: UIButton titleLabel -- does it do anything at all?

问题描述

我想制作一个类型为UIButtonTypeCustom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。以下代码看起来应该可以工作，但不会 - 没有标签显示，句点。

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：但这会给你一个我不喜欢的字体。 titleLabel方法不被弃用 - 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.

我之前已经遇到过好几次并且总是只是解决它，但我真的很想出来。有什么想法？

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

设置 titleLabel 的 text 这样的属性没有效果。而是在按钮上调用 -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]

原因是因为按钮可以有不同状态的不同标题（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适用于所有状态。

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：

此类提供设置方法按钮的标题，图像和其他外观属性。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.

您可以根据标签的颜色和阴影颜色自定义州。分别参见 -setTitleColor：forState 和 -setTitleShadowColor：forState 。 titleLabel 上的其他属性，例如 textAlignment 和 font ，应该正常工作，应该适用于所有控制状态。

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.

具体来说，请参阅 UIButton的文档's titleLabel property： 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，但这并不意味着你不能改变它自己属性的值，比如字体，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.

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