调整为UITextField打字时（通过使用自动布局） [英] Resize a UITextField while typing (by using Autolayout)

问题描述

我有一个UITableViewCell有两个UITextFields（无国界）。以下约束用于设置水平布局。

I have a UITableViewCell which has two UITextFields (without borders). The following constraints are used to set up the horizontal layout.

@| -10- [leftTextField（大于= 80）] - （大于= 10） - [rightTextField（大于= 40）] - 10 |

果然没什么特别的，和作品。

Nothing fancy, and works as expected.

正如你可以看到文本框上有正确的尺寸。较低的文本框开始与一个空的文本，因为空的文本是80点宽。当我键入​​文本，编辑文本框文本滚动到左边，它不会改变它的宽度。

As you can see the upper textField has the correct size. The lower textField started with an empty text, and because of the empty text it is 80 points wide. When I type text into the editing textField the text scrolls to the left, it does not change its width.

我不喜欢的是，文本框的宽度应在用户类型调整到该文本框。

I don't like that, the width of the textField should adjust while the user types into that textField.

在我看来，应该工作的开箱。通过实施 IBAction为为 UIControlEventEditingChanged 事件中，我可以证实，打字实际上改变了 intrinsicContentSize 中的UITextField的。

In my opinion that should work out of the box. By implementing a IBAction for the UIControlEventEditingChanged event I can confirm that typing actually changes the intrinsicContentSize of the UITextField.

但好，宽度不改变，直到文本框不再是第一个响应者。如果我把光标移动到另一个文本框的文本字段编辑的宽度设置。那是因为我想要的东西有点晚了。

But well, the width does not change until the textField is no longer the first responder. If I put the cursor into another textField the width of the edited textField is set. That's a bit late for what I want.

这些注释行的是什么我想没有任何成功：

These commented out lines is what I tried without any success:

- (IBAction)textFieldDidChange:(UITextField *)textField {
    [UIView animateWithDuration:0.1 animations:^{
//        [self.contentView removeConstraints:horizontalConstraints];
//        [self.contentView addConstraints:horizontalConstraints];
//        [self.contentView layoutIfNeeded];

//        [self.contentView setNeedsLayout];

//        [self.contentView setNeedsUpdateConstraints];
    }];
    NSLog(@"%@", NSStringFromCGSize(textField.intrinsicContentSize));
}

有谁知道我缺少的是什么？我应该怎么做，以使这项工作？

Does anybody know what I am missing? What could I try to make this work?

推荐答案

这对我来说是什么作品：

This is what works for me:

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

有趣的是，它好像它应该工作的开箱，鉴于这种<一个href=\"http://developer.apple.com/library/ios/documentation/UserExperience/Conceptual/AutolayoutPG/Articles/dividingResponsibility.html\">text从文档：

此外，如果一个视图更改属性，并改变影响
  内在内容大小，视图必须调用
  invalidateIntrinsicContentSize使布局系统的通告
  改变，可以重新布局。在您的视图类的实现，
  你必须确保如果任何属性的值赖以
  内在的大小取决于变化，可以调用
  invalidateIntrinsicContentSize。 例如，文本字段通话
  invalidateIntrinsicContentSize如果字符串值的变化。

In addition, if a property of a view changes and that change affects the intrinsic content size, the view must call invalidateIntrinsicContentSize so that the layout system notices the change and can re-layout. In the implementation of your view class, you must ensure that if the value of any property upon which the intrinsic size depends changes, you invoke invalidateIntrinsicContentSize. For example, a text field calls invalidateIntrinsicContentSize if the string value changes.

我最好的猜测是，一旦编辑完成后，不会在文本字段只要求invalidateIntrinsicContentSize。

My best guess is that the textfield only calls invalidateIntrinsicContentSize once editing has finished, not during.

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