UITextInput仅在iOS 9中返回空位置

Question

我正在尝试获取特定范围(UITextRange)的rect。问题是代码在iOS 10上运行得很好，我得到了range和rect。不幸的是，对于iOS 9，这行代码：

if let rangeStart = textInput.position(from: textInput.beginningOfDocument, offset: location) 

返回nil

let location = self.textView.firstRect(for: range)


extension NSRange {
    func toTextRange(textInput:UITextInput) -> UITextRange? {
        if let rangeStart = textInput.position(from: textInput.beginningOfDocument, offset: location),
            let rangeEnd = textInput.position(from: rangeStart, offset: length) {
            return textInput.textRange(from: rangeStart, to: rangeEnd)
        }
        return nil
    }
}

Answer 1

textView.isSelectable = true

这一行在iOS 9中是必需的(在iOS 10中不是必需的)。