将文本添加到UITextField您不能删除 [英] Adding text to UITextField you can't delete

问题描述

我想要做的是在 UITextField 开头添加一些文本，无法删除。当用户点击 UITextField 时，添加以下内容：

What I would like to do is to add some text at the beginning of UITextField that cannot be deleted. I add this text when the user taps on UITextField like this:

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField{

    if (textField.text.length == 0) {
        textField.text = @"myText";
    }

    return YES;
}

如何防止用户以正常方式删除此文本？ （ 不需要在TextField的顶部添加一个单独的 UILabel ）。
提前感谢！

How do I prevent the user from deleting this text in a normal way? (without adding a separate UILabel on top of the TextField, for example). Thanks in advance!

推荐答案

您可以在中实现此代码shouldChangeCharactersInRange delegate方法。

You can implement this code in shouldChangeCharactersInRange delegate method.

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    if (textField.text.length == 1 && [string isEqualToString:@""]) {//When detect backspace when have one character. 
        textField.text = @"myText";
    }
    return YES;
}

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