退出一个文本字段后，调用[otherTextField becomeFirstResponder]，下一个字段获得焦点。

这实际上是一个棘手的问题，因为通常你还想滚动屏幕或以其他方式调整文本字段的位置，以便在编辑时容易看到。只要确保做大量的测试，以不同的方式进入和退出文本字段，并提前离开(总是给用户一个选项，取消键盘，而不是进入下一个字段，通常在导航栏中有“完成”)

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.

没有usings标签，也没有为nextField/nextTextField添加属性，你可以尝试模拟TAB，其中"testInput"是你当前的活动字段:

if ([textInput isFirstResponder])
    [textInput.superview.subviews enumerateObjectsAtIndexes:
     [NSIndexSet indexSetWithIndexesInRange:
      NSMakeRange([textInput.superview.subviews indexOfObject:textInput]+1,
                  [textInput.superview.subviews count]-[textInput.superview.subviews indexOfObject:textInput]-1)]
                                                    options:0 usingBlock:^(UIView *obj, NSUInteger idx, BOOL *stop) {
                                                        *stop = !obj.hidden && [obj becomeFirstResponder];
                                                    }];
if ([textInput isFirstResponder])
    [textInput.superview.subviews enumerateObjectsAtIndexes:
     [NSIndexSet indexSetWithIndexesInRange:
      NSMakeRange(0,
                  [textInput.superview.subviews indexOfObject:textInput])]
                                                    options:0 usingBlock:^(UIView *obj, NSUInteger idx, BOOL *stop) {
                                                        *stop = !obj.hidden && [obj becomeFirstResponder];
                                                    }];

我已经实现了在视图层次结构中通过Responders导航的动态解决方案。其思想是，在整个层次结构中搜索下一个可能的响应器，根据需要向前或向后搜索。

UIView搜索扩展:

UIView+Cat.h

- (UIResponder *)getNextFirstResponder;
- (UIResponder *)getPreviousFirstResponder;

UIView+Cat.m

- (UIResponder *)getPreviousFirstResponder {
    if (!self.superview) {
        return nil;
    }
    
    BOOL hasreachedself = NO;
    for (NSInteger i = self.superview.subviews.count-1; i >= 0; i--) {
        UIView *v = [self.superview.subviews objectAtIndex:i];
        if (v == self) {
            hasreachedself = YES;
            continue;
        }
        if (!hasreachedself) continue;
        
        if ([v canBecomeFirstResponder] && !v.hidden) {
            return v;
        }
        UIResponder *subResponder = [self getNextFirstResponderInView:v];
        if (subResponder) {
            return subResponder;
        }
    }
    
    //search hierachicaly in superviews
    return [self.superview getPreviousFirstResponder];
}

- (UIResponder *)getNextFirstResponder {
    if (!self.superview) {
        return nil;
    }
    
    BOOL hasreachedself = NO;
    for (UIView *v in self.superview.subviews) {
        if (v == self) {
            hasreachedself = YES;
            continue;
        }
        if (!hasreachedself) continue;
        
        if ([v canBecomeFirstResponder] && !v.hidden) {
            return v;
        }
        UIResponder *subResponder = [self getNextFirstResponderInView:v];
        if (subResponder) {
            return subResponder;
        }
    }
    
    //search hierachicaly in superviews
    return [self.superview getNextFirstResponder];
}

- (UIResponder *)getNextFirstResponderInView:(UIView *)view {
    if ([view canBecomeFirstResponder] && !view.hidden) {
        return view;
    }
    for (UIView *v in view.subviews) {
        UIResponder *subResponder = [self getNextFirstResponderInView:v];
        if (subResponder) {
            return subResponder;
        }
    }
    return nil;
}

用法:添加UIToolbar到UITextField / UITextView(在类别或子类中):

- (void)addToolbarInputAccessoryView {
    UIToolbar *toolbar = [[UIToolbar alloc] initWithFrame:CGRectZero];
    UIBarButtonItem *prev = [[UIBarButtonItem alloc] initWithImage:[UIImage systemImageNamed:@"chevron.up"] style:UIBarButtonItemStylePlain target:self action:@selector(moveToPreviousFirstResponder)];
    UIBarButtonItem *next = [[UIBarButtonItem alloc] initWithImage:[UIImage systemImageNamed:@"chevron.down"] style:UIBarButtonItemStylePlain target:self action:@selector(moveToNextFirstResponder)];
    UIBarButtonItem *space = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
    UIBarButtonItem *done = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(hideKeyboard)];
    toolbar.items = @[prev, next, space, done];
    
    if ([[UITextField appearance] keyboardAppearance] == UIKeyboardAppearanceDark) {
        toolbar.barStyle = UIBarStyleBlack;
        toolbar.translucent = YES;
        [toolbar setBarTintColor:[UIColor blackColor]];
        [toolbar setTintColor:[UIColor whiteColor]];
    }
    
    [toolbar sizeToFit];
    
    self.inputAccessoryView = toolbar;
}

- (void)hideKeyboard {
    [self resignFirstResponder];
}

- (void)moveToNextFirstResponder {
    UIResponder *next = [self getNextFirstResponder];
    if (next) {
        [next becomeFirstResponder];
    }
    else {
        [self resignFirstResponder];
    }
}

- (void)moveToPreviousFirstResponder {
    UIResponder *prev = [self getPreviousFirstResponder];
    if (prev) {
        [prev becomeFirstResponder];
    }
    else {
        [self resignFirstResponder];
    }
}

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
            }
        }
    }
}

这是一个简单的解决方案在swift，没有标签使用，没有故事板技巧…

只需使用这个扩展:

extension UITextField{

    func nextTextFieldField() -> UITextField?{
        //field to return
        var returnField : UITextField?
        if self.superview != nil{
            //for each view in superview
            for (_, view) in self.superview!.subviews.enumerate(){
                //if subview is a text's field
                if view.isKindOfClass(UITextField){
                    //cast curent view as text field
                    let currentTextField = view as! UITextField
                    //if text field is after the current one
                    if currentTextField.frame.origin.y > self.frame.origin.y{
                        //if there is no text field to return already
                        if returnField == nil {
                            //set as default return
                            returnField = currentTextField
                        }
                            //else if this this less far than the other
                        else if currentTextField.frame.origin.y < returnField!.frame.origin.y{
                            //this is the field to return
                            returnField = currentTextField
                        }
                    }
                }
            }
        }
        //end of the mdethod
        return returnField
    }

}

并调用它像这样(例如)与你的textfield委托:

func textFieldShouldReturn(textField: UITextField) -> Bool {
    textField.resignFirstResponder()
    textField.nextTextFieldField()?.becomeFirstResponder()
    return true
}