设置新文本时,在UITextField中更改光标

Question

我发现了一件事.如果我设置肯定功能

- textField:shouldChangeCharactersInRange:replacementString:

光标停留在我输入的相同位置,如("|"=光标)

"|"     => Empty , type a
"a|"    => type b
"ab|"   => change cursor
"a|b"   => type c
"ac|b"  => type d
"acd|b" => change cursor
"ac|db" => type backspace
"a|db"  => type backspace again
"|db"   => *result*

但是,如果我必须更改文本,比如放入"-"倒数第二个字符,我会做逻辑事情并设置文本:

  [textField setText:newText];

但上面的示例将采用以下方式:

"|"      => Empty , type a
"a|"     => type b               (put character "-" automatic)
"a-b|"   => user change cursor
"a|-b"   => type c    
"ac-b|"  => type d               ## the cursor is in end ##
"acb-d|" => change cursor        ## "d" is in wrong place, the user have to  
                                 ## change cursor to reproduce the result above
"ac|b-d" => type backspace
"ab-d|"  => type backspace again   ## the cursor is in end again ##
"a-b|"   => *result*               ## I want delete "a" but it delete "d"

如何将光标设置为结果"|d-b"与第一个样本中的相同？或者更好的问题:如何更改UITextField中的文本和光标？

Answer 1

我找到了解决方案。我无法选择光标位置，但它可以满足我的要求。你必须使用UIKeyInput协议的功能有 2 个很好的功能：

- (void)insertText:(NSString *)text;
- (void)deleteBackward;

然后，重做我的测试用例，我有：

"|"      => Empty , type a
"a|"     => type b               (put character "-" automatic)
"a-b|"   => user change cursor
"a|-b"   => type c               (enter the character with a [textField insertText:@"c"]
"ac|-b"  => type d               (the same thing: [textField insertText:@"d"])
"acd|-b" => change cursor
"ac|d-b" => type backspace       (use a [textField deleteBackward])
"a|d-b"  => type backspace
"|d-b"   => *result*             (Work!!!)

您无法更改光标，但对于正常打字来说它可以解决问题！