当我将 UITextField 与 resignFirstResponder 结合使用时，它不是最多 1 个数字

Posted 2023-02-24

【中文标题】当我将 UITextField 与 resignFirstResponder 结合使用时，它不是最多 1 个数字

【英文标题】：UITextField is not a maximum of 1 number when I combine it with resignFirstResponder

【发布时间】：2014-05-31 11:41:15

【问题描述】：

检查最大数字是否为 1 的代码在我只使用那段代码时有效。但是当我使用 [becomFirstResponder] 添加自动跳转到下一个 UITextField 时，它不再起作用了。

非常感谢各位！

当

MyViewController.h

@interface GateKeeperViewController : UIViewController <UITextFieldDelegate>

@property (strong, nonatomic) IBOutlet UITextField *firstCodeField;
@property (strong, nonatomic) IBOutlet UITextField *secondCodeField;
@property (strong, nonatomic) IBOutlet UITextField *thirdCodeField;
@property (strong, nonatomic) IBOutlet UITextField *fourthCodeField;
@property (strong, nonatomic) IBOutlet UITextField *fifthCodeField;

MyViewController.m

@synthesize firstCodeField;
@synthesize secondCodeField;
@synthesize thirdCodeField;
@synthesize fourthCodeField;
@synthesize fifthCodeField;

- (void)viewDidLoad

    [super viewDidLoad];

    [self initFieldListeners];


-(void) initFieldListeners 

    firstCodeField.delegate = self;
    secondCodeField.delegate = self;
    thirdCodeField.delegate = self;
    fourthCodeField.delegate = self;
    fifthCodeField.delegate = self;

    [self.firstCodeField addTarget:self
                            action:@selector(textFieldEditing:)
                  forControlEvents:UIControlEventEditingChanged];

    [self.secondCodeField addTarget:self
                             action:@selector(textFieldEditing:)
                   forControlEvents:UIControlEventEditingChanged];

    [self.thirdCodeField addTarget:self
                            action:@selector(textFieldEditing:)
                  forControlEvents:UIControlEventEditingChanged];

    [self.fourthCodeField addTarget:self
                             action:@selector(textFieldEditing:)
                   forControlEvents:UIControlEventEditingChanged];

    [self.fifthCodeField addTarget:self
                            action:@selector(textFieldEditing:)
                  forControlEvents:UIControlEventEditingChanged];


- (void)textFieldEditing:(UITextField *)textField

    if(textField == self.firstCodeField )
        if ([self.firstCodeField.text length] == 1) 
            [self.secondCodeField becomeFirstResponder];
        
    

    if(textField == self.secondCodeField )
        if ([self.secondCodeField.text length] == 1) 
            [self.thirdCodeField becomeFirstResponder];
        
    

    if(textField == self.thirdCodeField )
        if ([self.thirdCodeField.text length] == 1) 
            [self.fourthCodeField becomeFirstResponder];
        
    

    if(textField == self.fourthCodeField )
        if ([self.fourthCodeField.text length] == 1) 
            [self.fifthCodeField becomeFirstResponder];
        
    


- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string

    NSUInteger newLength = [textField.text length] + [string length] - range.length;
    return (newLength > 1) ? NO : YES;

【参考方案1】：

我建议一个稍微不同的解决方案，在文本字段上使用target-action 以获得编辑事件的通知。这个想法是您的操作将在 shouldChangeCharactersInRange 方法之后执行。例如使用 3 个文本字段：

- (void)viewDidLoad

    [super viewDidLoad];

    [self.firstTextField addTarget:self
                            action:@selector(textFieldEditing:)
                  forControlEvents:UIControlEventEditingChanged];

    [self.secondTextField addTarget:self
                             action:@selector(textFieldEditing:)
                   forControlEvents:UIControlEventEditingChanged];



- (void)textFieldEditing:(UITextField *)textField

    if(textField == self.firstTextField )
        if ([self.firstTextField.text length] == 1) 
            [self.secondTextField becomeFirstResponder];
        
    

    if(textField == self.secondTextField )
        if ([self.secondTextField.text length] == 1) 
            [self.thirdTextField becomeFirstResponder];
        
    


- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string

    NSUInteger newLength = [textField.text length] + [string length] - range.length;
    return (newLength > 1) ? NO : YES;

仍然可以对此代码进行一些改进，但它应该可以帮助您入门。

【参考方案2】：

您在 shouldChangeCharactersInRange 委托执行操作之前设置了值。

意思是，您需要删除setText。

【讨论】：

不起作用。它跳到 secondCodeField，然后是fourthCodeField。

检查您的 IBOutlet 连接和委托。

【参考方案3】：

删除你的 - setText: 方法并这样做

创建一个局部变量来保存最后一个NSString和当前UITextField的引用

[NSTimer scheduledTimerWithTimeInterval:0.0 target:self selector:@selector(giveText:) userInfo:nil repeats:NO]; // instead of your - setText:

- (void)giveText:(id)sender 

    // set your text here lets say

    [currentTextField setText:lastString];

你必须在 return 语句之后设置文本，但这是不可能的，所以你滥用 NSTimer 来做到这一点。

例子：

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string 

    _lastString = string;
    _currentTextField = textField;

    if(firstCodeField == textField)

        // [firstCodeField setText:newString];

        [secondCodeField becomeFirstResponder];
    

    // ...... other ifs

    [NSTimer scheduledTimerWithTimeInterval:0.0 target:self selector:@selector(giveText:) userInfo:nil repeats:NO];