UITextView获取前一个字符-(即光标位置之前的字符)(iOS7)

Question

我不知道如何才能获得输入的前一个字符。换句话说，我怎样才能得到UITextView中光标之前的字符

NSInteger pos = [self.textInput offsetFromPosition:self.textInput.beginningOfDocument toPosition:textrange.start];
CGRect s = [self.textInput caretRectForPosition:self.textInput.selectedTextRange.start];
UITextRange *textrange = [self.textInput characterRangeAtPoint: s.origin];

谢谢,

亲切的问候,

Answer 1

谢谢这是我正在寻找的，我确实看到它之前实际上，但不是100%确定，我稍微修改了它，它很好。

    UITextPosition *beginning = self.textInput.beginningOfDocument;
    UITextPosition *selectionStart = self.textInput.selectedTextRange.start;
    UITextPosition *selectionEnd = self.textInput.selectedTextRange.end;
    NSInteger location = [self.textInput offsetFromPosition:beginning toPosition:selectionStart];
    NSInteger length = [self.textInput offsetFromPosition:selectionStart toPosition:selectionEnd];
    NSRange selectedRange = NSMakeRange(location,length);
    NSRange range = NSMakeRange(selectedRange.location-1,1);
    NSString *lastChar = [textValue substringWithRange:range];