Ios 为UITextField创建通用下一步按钮

我正在尝试创建一个与textField的标记一起工作的next按钮。 我在一个void类型方法中有这样一个方法：

for (UITextField *textField in self.view.subviews)
{
    if ([textField isKindOfClass:[UITextField class]])
    {
        if([textField isFirstResponder])
        {
            int i = _textFieldTag;  //starts as 0

            [[textField viewWithTag:i] resignFirstResponder];
            NSString *a = [(UITextField *)[textField viewWithTag:i] text];
            NSLog(@"TEXT 01 - %@", a);

            i = i + 1;
            NSLog(@"TAG 02 - %i", i);

            [[textField viewWithTag:i] becomeFirstResponder];
            NSString *b = [(UITextField *)[textField viewWithTag:i] text];
            NSLog(@"TEXT 02 - %@", b);
        }
    }
}

问题是，即使

i

增加1，

NSString*b

返回nil，并且不会像我预期的那样使该文本字段成为下一个响应者

它们在那里，标签存在，但不知何故，i的新值不被接受

---

有什么想法吗？

试着从以下位置替换所有电话：

[textField viewWithTag:i]

致：

---

您应该要求查看带有标记的视图而不是UITextField。

您的逻辑不正确，正如@Greg所说，您需要使用

[self.view viewWithTag:i]

来获得正确的视图。另外，为self.view指定一个不同于任何文本字段标记的标记（由于self.view的默认标记为0，所以出现了错误）。我想你希望你的逻辑是这样的：

-(IBAction)nextField:(id)sender {
    int i;
    for (UITextField *textField in self.view.subviews) {
        if ([textField isKindOfClass:[UITextField class]] && [textField isFirstResponder]) {
            [textField resignFirstResponder];
            NSString *a = textField.text;
            NSLog(@"TEXT 01 - %@", a);
            //i = textField.tag + 1; // use this line if you don't want to go back to the first text field
            i = (textField.tag == 4)? 0 : textField.tag + 1; //use this line if you want to cycle back to the first text field when you are on the last one. Replace the 4 with whatever is your highest tag. This also assumes that the tag of the first text field is 0.  
        }
    }

    NSLog(@"TAG 02 - %i", i);
    [[self.view viewWithTag:i] becomeFirstResponder];
    NSString *b = [(UITextField *)[self.view viewWithTag:i] text];
    NSLog(@"TEXT 02 - %@", b);
}

---

很抱歉导致应用程序崩溃***由于未捕获的异常“NSInvalidArgumentException”终止应用程序，原因：'-[UIView text]：无法识别的选择器已发送到实例0x8c15ca0'

-(IBAction)nextField:(id)sender {
    int i;
    for (UITextField *textField in self.view.subviews) {
        if ([textField isKindOfClass:[UITextField class]] && [textField isFirstResponder]) {
            [textField resignFirstResponder];
            NSString *a = textField.text;
            NSLog(@"TEXT 01 - %@", a);
            //i = textField.tag + 1; // use this line if you don't want to go back to the first text field
            i = (textField.tag == 4)? 0 : textField.tag + 1; //use this line if you want to cycle back to the first text field when you are on the last one. Replace the 4 with whatever is your highest tag. This also assumes that the tag of the first text field is 0.  
        }
    }

    NSLog(@"TAG 02 - %i", i);
    [[self.view viewWithTag:i] becomeFirstResponder];
    NSString *b = [(UITextField *)[self.view viewWithTag:i] text];
    NSLog(@"TEXT 02 - %@", b);
}