从NSRange创建UITextRange [英] Create UITextRange from NSRange

问题描述

我需要在textview中找到不同范围的像素框架。我正在使用 - （CGRect）firstRectForRange：（UITextRange *）范围; 来执行此操作。但是我无法找到如何实际创建 UITextRange 。

I need to find the pixel-frame for different ranges in a textview. I'm using the - (CGRect)firstRectForRange:(UITextRange *)range; to do it. However I can't find out how to actually create a UITextRange.

基本上这就是我在寻找的东西for：

Basically this is what I'm looking for:

- (CGRect)frameOfTextRange:(NSRange)range inTextView:(UITextView *)textView {

    UITextRange*range2 = [UITextRange rangeWithNSRange:range]; //DOES NOT EXIST 
    CGRect rect = [textView firstRectForRange:range2];
    return rect;
}

Apple说必须子类 UITextRange 和 UITextPosition 以采用 UITextInput 协议。我不这样做，但我还是尝试了，按照doc的示例代码并将子类传递给 firstRectForRange ，这导致崩溃。

Apple says one has to subclass UITextRange and UITextPosition in order to adopt the UITextInput protocol. I don't do that, but I tried anyway, following the doc's example code and passing the subclass to firstRectForRange which resulted in crashing.

如果有更简单的方法可以在文本视图中添加不同颜色的 UILables ，请告诉我。我尝试使用UIWebView，内容可编辑设置为TRUE，但我不喜欢与JS通信，并且着色是我唯一需要的东西。

If there is a easier way of adding different colored UILables to a textview, please tell me. I have tried using UIWebView with content editable set to TRUE, but I'm not fond of communicating with JS, and coloring is the only thing I need.

提前致谢。

推荐答案

您可以使用方法<$创建文本范围C $ C> textRangeFromPosition：toPosition 。此方法需要两个位置，因此您需要计算范围开始和结束的位置。这是通过方法 positionFromPosition：offset 完成的，它从另一个位置和一个字符偏移量返回一个位置。

You can create a text range with the method textRangeFromPosition:toPosition. This method requires two positions, so you need to compute the positions for the start and the end of your range. That is done with the method positionFromPosition:offset, which returns a position from another position and a character offset.

- (CGRect)frameOfTextRange:(NSRange)range inTextView:(UITextView *)textView
{
    UITextPosition *beginning = textView.beginningOfDocument;
    UITextPosition *start = [textView positionFromPosition:beginning offset:range.location];
    UITextPosition *end = [textView positionFromPosition:start offset:range.length];
    UITextRange *textRange = [textView textRangeFromPosition:start toPosition:end];
    CGRect rect = [textView firstRectForRange:textRange];
    return [textView convertRect:rect fromView:textView.textInputView];
}

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