TextField 委托 shouldChangeCharactersInRange [英] TextField delegate shouldChangeCharactersInRange

问题描述

为什么 shouldChangeCharactersInRange 不立即更新文本字段.1 延迟一个字符.

Why doesn't the shouldChangeCharactersInRange update the textfield right away. It is 1 delayed by one character.

例如，下载此文件:https://www.dropbox.com/s/goljs3d6lcxutxy/UITextField%20Tutorial.zip?dl=0

将以下代码添加到

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {

方法

print(textField.text)

看看它是如何延迟一个字符的.我希望它在我输入文本时更新而不是延迟.

see how it is delayed by one character. I want it to be updated as I type the text not one delayed.

推荐答案

该方法询问您是否应该采用 replacementString 并将其添加到 textField.text.在你按下键盘上的一个键之后，屏幕上出现字母之前，它会立即被调用.

That method is asking you if it should take the replacementString and add it onto textField.text. It is called immediately after you press a key on the keyboard and before letter appears on screen.

要查看新字符串将是什么，您需要这样做.

To see what the new string will be, you'd need to to something like this.

let newText = textField.text.stringByReplacingCharactersInRange(range, withString: string)
print(newText)

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