限制 UITextview 的行数 [英] Limit the number of lines for UITextview

问题描述

我想知道如何限制用户在编辑 UITextField 时可以输入的 LINES(不是其他问题中询问的字符)的数量.

I was wondering how to limit the amount of LINES (not characters as asked in other questions) a user can enter when editing a UITextField.

理想情况下，我想将输入限制为最大值.10 行.

Ideally, I would like to limit the input to max. 10 lines.

我需要从哪里开始?我用一种方法来做到这一点吗?在

Where would I need to start? Do I do this with a method? In

 - (BOOL)textViewShouldBeginEditing:(UITextView *)aTextView

推荐答案

你的想法是对的，但方法是错误的.textView:shouldChangeTextInRange:replacementText: 每当文本要改变时调用；您可以使用其 text 属性访问文本视图的当前内容，并且您可以使用 [textView.text stringByReplacingCharactersInRange:range withString:replacementText 从传递的范围和替换文本中构造新内容].然后，您可以计算行数并返回 YES 以允许更改或 NO 拒绝更改.

You have the right idea, but the wrong method. textView:shouldChangeTextInRange:replacementText: is called whenever the text is going to change; you can access the current content of the text view using its text property, and you can construct the new content from the passed range and replacement text with [textView.text stringByReplacingCharactersInRange:range withString:replacementText]. You can then count the number of lines and return YES to allow the change or NO to reject it.

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