stringByReplacingCharactersInRange如何在swift中工作？

Question

我在objective-c中有这段代码：

[textField.text stringByReplacingCharactersInRange:range withString:string];

尝试转换为swift，如下所示：

textField.text.stringByReplacingCharactersInRange(range, withString: string)

但是编译器说Int is not identical to 'String.index'

我应该如何修改表达式？

我在UITextFieldDelegate方法中使用了objective-c / swift表达式：

func textField(textField: UITextField!,
    shouldChangeCharactersInRange range: NSRange,
    replacementString string: String!) -> Bool {

Answer 1

使用bridgeToObjectiveC()

textField.text.bridgeToObjectiveC().stringByReplacingCharactersInRange(range, withString: string)

它会更加明确

var st = "abc"
str.bridgeToObjectiveC().stringByReplacingCharactersInRange(NSMakeRange(2,1), withString:"r")

也可以对NSString进行显式投射，而不需要bridgeToObjectiveC

var st = "abc" as NSString
let abc = st.stringByReplacingCharactersInRange(NSMakeRange(2, 3), withString: "abc")