在ios中获取UITextField的光标位置 [英] Getting the cursor position of UITextField in ios

问题描述

我正在尝试控制UITextField中的光标位置。用户不能一次插入多个字符到文本字段的中间。它将它移动到文本字段的末尾。所以SO中的帖子：控制UITextField中的光标位置它解决了我的问题。但我需要知道当前光标位置。

I am trying to control the cursor position in the UITextField. Users cannot insert more than one character at a time into the middle of the text field. It moves it to the end of the textfield. So this post in SO: Control cursor position in UITextField It solves my problem. But I need to know the current cursor position.

我的代码如下所示：

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
   if (textField.tag == 201) 
   {
     [myclass selectTextForInput:textField atRange:NSMakeRange(idx, 0)];
   }
}

它在idx给我一个错误。我怎么找到？

It is giving me an error at idx. How do I find that?

推荐答案

UITextField 符合 UITextInput 协议，其中包含获取当前选择的方法。但这些方法很复杂。你需要这样的东西：

UITextField conforms to the UITextInput protocol which has methods for getting the current selection. But the methods are complicated. You need something like this:

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    if (textField.tag == 201) {
        UITextRange *selRange = textField.selectedTextRange;
        UITextPosition *selStartPos = selRange.start;
        NSInteger idx = [textField offsetFromPosition:textField.beginningOfDocument toPosition:selStartPos];

        [myclass selectTextForInput:textField atRange:NSMakeRange(idx, 0)];
    }
}

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