使用自动布局使用文本水平调整 UITextField 的大小 [英] Resize UITextField horizontally with text using Auto Layout

问题描述

可以在此处找到演示以下问题的示例项目:https://github.com/markdorison/UITextFieldContentSizeExample/

An example project to demonstrate the below issue can be found here: https://github.com/markdorison/UITextFieldContentSizeExample/

我正在尝试使用自动布局让 UITextField 使用其包含的文本内容来扩大/缩小其宽度.我创建了优先级为 749 的前导和尾随约束(而不是默认值:1000).我还尝试将这些约束的优先级一直降低到 1，但这似乎对行为没有明显影响.

I am attempting to have a UITextField grow/shrink its width with the text content it contains using Auto Layout. I have created leading and trailing constraints with a priority of 749 (as opposed to the default: 1000). I have also tried lowering the priority of these constraints all the way down to 1, but this does not seem to have a noticeable effect on the behavior.

通过监听 UIControlEventEditingChanged 事件，我触发了内在内容大小的重置:

By listening to the UIControlEventEditingChanged event, I am triggering a reset of the intrinsicContentSize:

- (IBAction)textFieldDidChange:(UITextField *)textField {
    [UIView animateWithDuration:0.1 animations: ^{
        [textField invalidateIntrinsicContentSize];
    }];
}

这种方法几乎有效.有两个问题:

This approach almost works. There are two issues:

1. 我正在设置一个占位符.无论占位符有多宽，UITextField 的 intrinsicContentSize 的宽度都不会低于它.因此，如果占位符的宽度为 130，并且我开始输入，则文本视图的宽度将保持在 130，直到我输入的宽度达到大于 130；在此之后，文本视图将增长.

1. I am setting a placeholder. However wide the placeholder is, the width of the UITextField's intrinsicContentSize will never drop below it. So if the placeholder's width is 130, and I begin to type, the text view's width will remain at 130 until what I am typing reaches a width greater than 130; after this the text view will grow.

在我的示例中，我在 UITextField 下方放置了一个 UITextView.当我输入 UITextField 时，它的宽度会按预期增长.然后我可以点击 UITextView 并编辑文本.如果我然后返回并编辑 UITextView，它的宽度将不再按预期增长/缩小.UITextField 的 intrinsicContentSize 属性返回的值从 {192, 28} 等标准外观的整数变为 {191.536, 27.959999}.

In my example I have placed a UITextView below the UITextField. When I type in the UITextField, its width grows as expected. I can then tap into the UITextView and edit the text. If I then go back and edit the UITextView, its width no longer grows/shrinks as expected. The values being returned by the UITextField's intrinsicContentSize property go from being standard-looking integers like {192, 28}, to {191.536, 27.959999}.

任何帮助将不胜感激！

推荐答案

我正在设置一个占位符.无论占位符有多宽，UITextField 的 intrinsicContentSize 的宽度都不会低于它.因此，如果占位符的宽度为 130，并且我开始输入，则文本视图的宽度将保持在 130，直到我输入的宽度达到大于 130；在此之后，文本视图将增长.

I am setting a placeholder. However wide the placeholder is, the width of the UITextField's intrinsicContentSize will never drop below it. So if the placeholder's width is 130, and I begin to type, the text view's width will remain at 130 until what I am typing reaches a width greater than 130; after this the text view will grow.

我认为您必须使用 UITextField 子类，您可以在其中设置 intrinsicContentSize，覆盖 intrinsicContentSize 的默认行为显然是根据占位符来调整大小的方法.

I think you'll have to use a UITextField subclass where you get to set the instrinsicContentSize, overriding the default behavior of the intrinsicContentSize method which is evidently to size based on the placeholder.

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