Ios 如何启用/禁用UITextField'；s inputAccessoryView按钮？

我已经创建了一个UIToolBar作为inputAccessoryView，其中包含一个“下一个”和“上一个”按钮，该按钮将在我的视图控制器中的文本字段中循环

我已经在UITextField上创建了一个基于的类别，它向textField添加了一个指向下一个/上一个textField的属性

我可以让它在文本字段中前后循环，但只能循环一次，然后我的按钮将被永久禁用。此外，当最后一个文本字段处于焦点时，我还需要再点击下一个按钮一次（3个文本字段点击4次），以使其禁用下一个按钮-与上一个按钮相同，当我在第一个文本字段时，我必须回按一次

// ViewController.h
@interface DetailViewController : UIViewController <UINavigationControllerDelegate, UIImagePickerControllerDelegate, UITextFieldDelegate, UIPopoverControllerDelegate> {

    __weak IBOutlet UITextField *valueField;
    __weak IBOutlet UITextField *nameField;
    __weak IBOutlet UITextField *serialNumberField;

}

@property (nonatomic, strong) UITextField *currentTextField;

- (IBAction)nextTextField:(id)sender;
- (IBAction)prevTextField:(id)sender;


// ViewController.m
- (void)viewDidLoad {
    //...

    nameField.delegate = self;
    nameField.nextTextField = serialNumberField;
    nameField.prevTextField = nil;

    serialNumberField.delegate = self;
    serialNumberField.nextTextField = valueField;
    serialNumberField.prevTextField = nameField;

    valueField.delegate = self;
    valueField.prevTextField = serialNumberField;
    valueField.nextTextField = nil;

    //...
}

- (void)viewWillAppear:(BOOL)animated {
    //UIToolBar for inputAccessoryView
    UIToolbar *toolBar = [[UIToolbar alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, 50)];
    UIBarButtonItem *nextField = [[UIBarButtonItem alloc] initWithTitle:@"\U00003009"
                                                                  style:UIBarButtonItemStylePlain
                                                                 target:self
                                                                 action:@selector(nextTextField:)];
    UIBarButtonItem *prevField = [[UIBarButtonItem alloc] initWithTitle:@"\U00003008"
                                                                  style:UIBarButtonItemStylePlain
                                                                 target:self
                                                                 action:@selector(prevTextField:)];
    UIBarButtonItem *space = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
    UIBarButtonItem *done = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(backgroundTapped:)];
    NSArray *toolBarButtons = @[prevField, nextField, space, done];
    toolBar.items = toolBarButtons;

    nameField.inputAccessoryView  = toolBar;
    valueField.inputAccessoryView = toolBar;
    serialNumberField.inputAccessoryView = toolBar;
}

    - (IBAction)nextTextField:(id)sender {
    UITextField *next = self.currentTextField.nextTextField;

    if (!next) {
        [sender setEnabled:NO];
    } else {
        [sender setEnabled:YES];
        [next becomeFirstResponder];
    }
}


- (IBAction)prevTextField:(id)sender {
    UITextField *prev = self.currentTextField.prevTextField;

    if (!prev) {
        [sender setEnabled:NO];
    } else {
        [sender setEnabled:YES];
        [prev becomeFirstResponder];
    }
}

//ViewController.h
@界面详细信息ViewController:UIViewController{
__弱ibuitextfield*valueField；
__弱ibuitextfield*nameField；
__弱ibuitextfield*serialNumberField；
}
@属性（非原子，强）UITextField*currentTextField；
-（iAction）nextTextField:（id）发送方；
-（iAction）prevTextField:（id）发件人；
//ViewController.m
-（无效）viewDidLoad{
//...
nameField.delegate=self；
nameField.nextTextField=serialNumberField；
nameField.prevTextField=nil；
serialNumberField.delegate=self；
serialNumberField.nextTextField=valueField；
serialNumberField.prevTextField=名称字段；
valueField.delegate=self；
valueField.prevTextField=serialNumberField；
valueField.nextTextField=nil；
//...
}
-（无效）视图将显示：（BOOL）动画{
//inputAccessoryView的UIToolBar
UIToolbar*工具栏=[[UIToolbar alloc]initWithFrame:CGRectMake（0,0，self.view.frame.size.width，50）]；
UIBarButtonItem*nextField=[[UIBarButtonItem alloc]initWithTitle:@“\U00003009”
风格：uibarbuttonimstyleplain
目标：自我
操作：@selector（nexttexfield:）]；
UIBarButtonItem*prevField=[[UIBarButtonItem alloc]initWithTitle:@“\U00003008”
风格：uibarbuttonimstyleplain
目标：自我
操作：@选择器（prevTextField:）]；
UIBarButtonItem*space=[[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarbuttonSystemFlexibleSpace目标：无操作：无]；
UIBarButtonItem*done=[[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarbuttonSystemDone目标：自我操作：@selector（backgroundTapped:）]；
NSArray*工具栏按钮=@[prevField，nextField，space，done]；
toolBar.items=工具栏按钮；
nameField.inputAccessoryView=工具栏；
valueField.inputAccessoryView=工具栏；
serialNumberField.inputAccessoryView=工具栏；
}
-（iAction）nextTextField:（id）发件人{
UITextField*next=self.currentTextField.nextTextField；
如果（！下一个）{
[发送方设置已启用：否]；
}否则{
[发送方设置已启用：是]；
[下一步成为第一响应者]；
}
}
-（iAction）prevTextField:（id）发件人{
UITextField*prev=self.currentTextField.prevTextField；
如果（！prev）{
[发送方设置已启用：否]；
}否则{
[发送方设置已启用：是]；
[先前成为第一反应者]；
}
}

我认为部分问题在于，您正在使用一种方法来处理条形按钮的启用/禁用，该方法仅在点击其中一个条形按钮后调用。最好将BarButtonims设置为视图控制器的属性（以便您可以在需要时启用/禁用它们），然后在UITextField的“textFieldShouldBeginEditing”委托方法中处理条形按钮项的启用/禁用

比如说：

- (void)viewWillAppear:(BOOL)animated {
    //UIToolBar for inputAccessoryView
    UIToolbar *toolBar = [[UIToolbar alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, 50)];
    self.moveToNextFieldButton = [[UIBarButtonItem alloc] initWithTitle:@"\U00003009"
                                                                  style:UIBarButtonItemStylePlain
                                                                 target:self
                                                                 action:@selector(nextTextField:)];
    self.moveToPrevFieldButton = [[UIBarButtonItem alloc] initWithTitle:@"\U00003008"
                                                                  style:UIBarButtonItemStylePlain
                                                                 target:self
                                                                 action:@selector(prevTextField:)];
    UIBarButtonItem *space = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
    UIBarButtonItem *done = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(backgroundTapped:)];
    NSArray *toolBarButtons = @[self.moveToPrevFieldButton, self.moveToNextFieldButton, space, done];
    toolBar.items = toolBarButtons;

    nameField.inputAccessoryView  = toolBar;
    valueField.inputAccessoryView = toolBar;
    serialNumberField.inputAccessoryView = toolBar;
}

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

    UITextField *next = textField.nextTextField;
    UITextField *prev = textField.prevTextField;
    self.moveToNextFieldButton.enabled = next != nil;
    self.moveToPrevFieldButton.enabled = prev != nil;

    return YES;
}

- (IBAction)nextTextField:(id)sender {
    UITextField *next = self.currentTextField.nextTextField;

    if (next) {
        [next becomeFirstResponder];
    } 
}


- (IBAction)prevTextField:(id)sender {
    UITextField *prev = self.currentTextField.prevTextField;

    if (prev) {
        [prev becomeFirstResponder];
    }
}