检测轻拍的角色。 UITextView characterRangeAtPoint始终返回nil

问题描述

我正在尝试确定，已经点击了 UITextView 中的哪个特定字符。我尝试使用 characterRangeAtPoint：方法。但它始终返回nil，无论在 UITextView 中我点击。
我甚至编写并运行以下代码：

I'm trying to determine, which particular character in UITextView has been tapped. I tried to use characterRangeAtPoint: method. But it always returns nil, wherever in the UITextView I tap.I even wrote and run the following piece of code:

for (int x = 0; x<1000; x++) {
    pos.x = x;
    for (int y = 0; y<1000; y++) {
        pos.y = y;
        UITextRange * range = [textView characterRangeAtPoint:pos];
        if (range!=nil) {
            NSLog(@"x: %f, y: %f", pos.x, pos.y);
        }
    }
}

好吧，它永远不会到达 NSLog 字符串。
我做错了什么？

Well, it never reaches the NSLog string.What am I doing wrong?

推荐答案

这是iOS 7的错误。 characterRangeAtPoint：总是返回 nil ，除非事先至少选择过一次文本。

This is an iOS 7 bug. characterRangeAtPoint: always returns nil, unless some text has been selected at least once beforehand.

作为解决方法，您可以事先调用 setSelectedRange：或 setSelectedTextRange：，但随后 textView 会突出显示您的选择。我提出了以下解决方案：

As a workaround, you could call setSelectedRange: or setSelectedTextRange: beforehand, but then the textView would highlight your selection. I came up with the following solution:

[textView select:textView];
[textView setSelectedTextRange:nil];

调用这两种方法后， characterRangeAtPoint：将按预期开始工作。

After you call these two methods, characterRangeAtPoint: will start working as expected.

请注意，在初始化 textView 之后，您只需要调用一次。

Note that you just need to call this once after textView has been initialized.

编辑：我的答案是从编辑的，除非事先选择了一些文字到除非当前选择了某些文字。这是错误的：当前不需要选择文本，只需选择一次。随后对 setSelectedRange：的所有后续调用都将成功，如我的说明中所述。为了进一步明确而进行了编辑。

my answer was edited from "unless some text has been selected beforehand" to "unless some text is currently selected". This is wrong: text doesn't need to be currently selected, it just has to be selected once. All subsequent calls to setSelectedRange: will then be successful, as stated in my note. Edited back for further clarity.

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