我尝试使用一种更复杂的方法来解决这个问题，该方法基于为UITableView中的每个单元格(或UITextField)分配一个稍后可以检索的唯一标签值: activate-next-uitextfield-in-uitableview-ios

我希望这能有所帮助!

我喜欢Anth0和Answerbot已经提出的面向对象解决方案。然而，我正在开发一个快速而小型的POC，所以我不想让子类和类别使事情变得混乱。

另一个简单的解决方案是创建一个字段的NSArray，并在按下next时查找下一个字段。不是面向对象的解决方案，而是快速、简单且易于实现。此外，您可以一目了然地查看和修改排序。

下面是我的代码(基于这个线程中的其他答案):

@property (nonatomic) NSArray *fieldArray;

- (void)viewDidLoad {
    [super viewDidLoad];

    fieldArray = [NSArray arrayWithObjects: firstField, secondField, thirdField, nil];
}

- (BOOL) textFieldShouldReturn:(UITextField *) textField {
    BOOL didResign = [textField resignFirstResponder];
    if (!didResign) return NO;

    NSUInteger index = [self.fieldArray indexOfObject:textField];
    if (index == NSNotFound || index + 1 == fieldArray.count) return NO;

    id nextField = [fieldArray objectAtIndex:index + 1];
    activeField = nextField;
    [nextField becomeFirstResponder];

    return NO;
}

I always return NO because I don't want a line break inserted. Just thought I'd point that out since when I returned YES it would automatically exit the subsequent fields or insert a line break in my TextView. It took me a bit of time to figure that out. activeField keeps track of the active field in case scrolling is necessary to unobscure the field from the keyboard. If you have similar code, make sure you assign the activeField before changing the first responder. Changing first responder is immediate and will fire the KeyboardWasShown event immediately.

Swift 3解决方案，使用UITextField的有序数组

func nextTextField() {
    let textFields = // Your textfields array

    for i in 0 ..< textFields.count{
        if let textfield = textFields[i], textfield.isFirstResponder{
            textfield.resignFirstResponder()
            if i+1 < textFields.count, let nextextfield = textFields[i+1]{
                nextextfield.becomeFirstResponder()
                return
            }
        }
    }
}

if (cell == nil)
{
    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
    txt_Input = [[ UITextField alloc] initWithFrame:CGRectMake(0, 10, 150, 30)];
    txt_Input.tag = indexPath.row+1;
    [self.array_Textfields addObject:txt_Input]; // Initialize mutable array in ViewDidLoad
}

-(BOOL)textFieldShouldReturn:(UITextField *)textField
{

    int tag = ( int) textField.tag ;
    UITextField * txt = [  self.array_Textfields objectAtIndex:tag ] ;
    [ txt becomeFirstResponder] ;
    return YES ;
}

下面是一个swift3版本的Anth0的答案。我把它贴在这里，以帮助任何想要利用他的伟大答案的敏捷开发人员!当您设置关联对象时，我擅自添加了一个返回键类型“Next”。

extension UITextField {

  @nonobjc static var NextHashKey: UniChar = 0

  var nextTextField: UITextField? {
    get {
      return objc_getAssociatedObject(self, 
        &UITextField.NextHashKey) as? UITextField
    }
    set(next) {
     self.returnKeyType = UIReturnKeyType.next
     objc_setAssociatedObject(self,
      &UITextField.NextHashKey,next,.OBJC_ASSOCIATION_RETAIN_NONATOMIC)
    }
  }
}

下面是另一个扩展，它显示了使用上述代码循环遍历UITextFields列表的可能性。

extension UIViewController: UITextFieldDelegate {
 public func textFieldShouldReturn(_ textField: UITextField) -> Bool {
   guard let next = textField.nextTextField else {
     textField.resignFirstResponder()
     return true
   }

    next.becomeFirstResponder()
    return false
  }
}

然后在你的ViewController或者其他地方，你可以像这样设置你的文本框。

@IBOutlet fileprivate weak var textfield1: UITextField!
@IBOutlet fileprivate weak var textfield2: UITextField!
@IBOutlet fileprivate weak var textfield3: UITextField!

...

[textfield1, textfield2, textfield3].forEach{ $0?.delegate = self }

textfield1.nextTextField = textfield2
textfield2.nextTextField = textfield3
// We don't assign a nextTextField to textfield3 because we want 
// textfield3 to be the last one and resignFirstResponder when 
// the return button on the soft keyboard is tapped.

这是我对这个问题的解决方案。

为了解决这个问题(因为我讨厌依赖标签来做事情)，我决定向UITextField对象添加一个自定义属性。换句话说，我在UITextField上创建了一个这样的类别:

UITextField + Extended.h

@interface UITextField (Extended)

@property(retain, nonatomic)UITextField* nextTextField;

@end

UITextField +扩展。m

#import "UITextField+Extended.h"
#import <objc/runtime.h>

static char defaultHashKey;

@implementation UITextField (Extended)

- (UITextField*) nextTextField { 
    return objc_getAssociatedObject(self, &defaultHashKey); 
}

- (void) setNextTextField:(UITextField *)nextTextField{
    objc_setAssociatedObject(self, &defaultHashKey, nextTextField, OBJC_ASSOCIATION_RETAIN_NONATOMIC); 
}

@end

下面是我如何使用它:

UITextField *textField1 = ...init your textfield
UITextField *textField2 = ...init your textfield
UITextField *textField3 = ...init your textfield

textField1.nextTextField = textField2;
textField2.nextTextField = textField3;
textField3.nextTextField = nil;

实现textFieldShouldReturn方法:

- (BOOL)textFieldShouldReturn:(UITextField *)theTextField {

    UITextField *next = theTextField.nextTextField;
    if (next) {
        [next becomeFirstResponder];
    } else {
        [theTextField resignFirstResponder];
    }

    return NO; 
}

我现在有一个UITextField的链表，每一个都知道下一个是谁。

希望能有所帮助。