Question

我有一个简单的应用程序，可以帮助招聘人员在活动期间收集信息。一个表单字段用于电话号码，我想要一种简单的方法来重新格式化用户输入的电话号码。

电话号码应随着用户类型的变化而变化，因此一串数字的示例输出应如下所示：

1
1 (20)
1 (206) 55
1 (206) 555-55
1 (206) 555-5555

或者，如果用户没有在区号前输入1，则电话号码会像这样发展：

(20)
(206) 55
(206) 555-55
(206) 555-5555

如果电话号码太长，那么它应该只显示一串简单的数字：

20655555555555555

Answer 1

以下是我所做的：UITextFieldDelegate通过获取textField:shouldChangeCharactersInRange :replacementString:的文本并运行我编写的一个小方法来处理UITextField方法：

-(void)updatePhoneNumberWithString:(NSString *)string {

    NSMutableString *finalString = [NSMutableString new];
    NSMutableString *workingPhoneString = [NSMutableString stringWithString:string];

    if (workingPhoneString.length > 0) {
    //This if statement prevents errors when the user deletes the last character in the textfield.

        if ([[workingPhoneString substringToIndex:1] isEqualToString:@"1"]) {
        //If the user typed a "1" as the first digit, then it's a prefix before the area code.
            [finalString appendString:@"1 "];
            [workingPhoneString replaceCharactersInRange:NSMakeRange(0, 1) withString:@""];
        }

        if (workingPhoneString.length < 3) {
        //If the user is dialing the area code...
            [finalString appendFormat:[NSString stringWithFormat:@"(%@)", workingPhoneString]];

        } else if (workingPhoneString.length < 6) {
        //If the user is dialing the 3 digits after the area code...
            [finalString appendFormat:[NSString stringWithFormat:@"(%@) %@", 
                                       [workingPhoneString substringWithRange:NSMakeRange(0, 3)], 
                                       [workingPhoneString substringFromIndex:3]]];

        } else if (workingPhoneString.length < 11) {
        //If the user is dialing the last 4 digits of the phone number...
            [finalString appendFormat:[NSString stringWithFormat:@"(%@) %@-%@", 
                                       [workingPhoneString substringWithRange:NSMakeRange(0, 3)], 
                                       [workingPhoneString substringWithRange:NSMakeRange(3, 3)],
                                       [workingPhoneString substringFromIndex:6]]];
        } else {
        //If the user's typed in a bunch of characters, then just show the full string.
            finalString = phoneString;
        }

        phoneNumberField.text = finalString;
    } else {
    //If the user changed the textfield to contain no text at all...
        phoneNumberField.text = @"";
    }

}

希望这能帮到你！

如何在美国将NSString格式化为电话号码？

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