如何启用/禁用 UITextField 的 inputAccessoryView 按钮？

Posted 2023-03-15

【中文标题】如何启用/禁用 UITextField 的 inputAccessoryView 按钮？

【英文标题】：How can I enable/disable a UITextField's inputAccessoryView buttons?

【发布时间】：2013-12-17 20:17:45

【问题描述】：

我创建了一个 UIToolBar 作为 inputAccessoryView，其中包含一个下一个和上一个按钮，这些按钮将在我的视图控制器中的 textFields 中循环。

我在 UITextField 上创建了一个基于 third SO answer on this page 的类别，它向指向下一个/上一个 textField 的 textField 添加了一个属性。

我可以让它在文本字段中向前和向后循环，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 textField 处于焦点时，我仍然需要再次点击下一个按钮（4 个点击 3 个 textFields）才能禁用下一个按钮 - 与上一个按钮相同，我必须点击一次后我'm 在第一个文本字段中。

// 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];
    

【参考方案1】：

我认为部分问题在于您正在处理启用/禁用栏按钮的方法，该方法仅在点击其中一个栏按钮后才调用。最好将 barbuttonitems 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”委托方法中处理启用/禁用栏按钮项。

所以，是这样的：

- (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];