使用 secureTextEntry 为 UITextField 选择键盘语言

Question

我遇到了更改密码字段语言的问题。在我的应用程序中，我需要在不关心当前语言环境的情况下以希伯来语输入登录名/密码。当我尝试输入登录时，就可以了，我可以将键盘更改为希伯来语并输入登录。但是当我尝试在受保护的文本字段中输入密码时，出现的键盘没有选择语言按钮，所以我只能输入英文字母。

问题是登录名/密码可以是英语或希伯来语。

如何将选择语言按钮放到受保护的文本字段中？

Answer 1

没有找到解决办法。不得不做这个sn-p：

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
textField.text = [textField.text stringByReplacingCharactersInRange:range withString:string];

NSString *pass = password;
pass = [pass stringByReplacingCharactersInRange:range withString:string];

[password release];
password = nil;

password = [[NSString stringWithString:pass] retain];

[self hideTextInTextFieldExceptOne:string];

[self performSelector:@selector(hideTextInTextField) withObject:self afterDelay:1.0];

return NO;
}

- (void)hideTextInTextFieldExceptOne:(NSString *)string
{    
int lenght = [passwordTextField.text length];

for (int i = 0; i < lenght-1; i++)
{
    NSRange range = NSMakeRange(i, 1);
    passwordTextField.text = [passwordTextField.text stringByReplacingCharactersInRange:range withString:@"*"];
}
}

- (void)hideTextInTextField
{
NSUInteger lenght = [passwordTextField.text length];
passwordTextField.text = @"";

for (int i = 0; i < lenght; i++)
{
    passwordTextField.text = [passwordTextField.text stringByAppendingString:@"*"];
}
}

Answer 2

很遗憾，此处发布的解决方案不适用于具有复合字符的语言（如韩语）。

像韩语（Hangul）这样的语言有一个复合字符，其中每个字母由多个符号组成。比如‘ㅁ’、‘ㅏ’和‘ㄴ’都是单独的字符，但是组合起来就变成了‘만’，被当作一个字母来处理。

这是适用于所有语言的解决方案。

在 UITextField 上放置一个 UILabel。将 UILabel 的框架设置为比 UITextField 略小，使其位于 UITextField 内，但仍会遮挡 UITextField 的文本。 textField: shouldChangeCharactersInRange:withReplacementString 在文本完成之前被调用。这意味着我们需要自己完成文本。这对于像韩语这样的复合字符语言更难做到。相反，注册 UITextFieldTextDidChangeNotification，它将在新文本出现在 UITextField 上后调用。

@interface MKSecureTextField()<UITextFieldDelegate>
@property (nonatomic, strong) UITextField* textField;
@property (nonatomic, strong) UILabel* hideLabel;
@property (nonatomic, strong) NSTimer* hideTimer;
@property (nonatomic, strong) NSTimer* blinkTimer;
@end

@implementation MKSecureTextField


- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self)
    {
        self.textField = [[UITextField alloc] initWithFrame:CGRectMake(0, 0, frame.size.width, frame.size.height)];
        _textField.userInteractionEnabled = YES;
        _textField.borderStyle = UITextBorderStyleRoundedRect;
        _textField.font = [UIFont systemFontOfSize:14];
        _textField.placeholder = @"enter text";
        _textField.autocorrectionType = UITextAutocorrectionTypeNo;
        _textField.keyboardType = UIKeyboardTypeDefault;
        _textField.returnKeyType = UIReturnKeyDone;
        _textField.clearButtonMode = UITextFieldViewModeWhileEditing;
        _textField.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;
        _textField.delegate = self;

        self.hideLabel = [[UILabel alloc] initWithFrame:CGRectMake(6, 5, frame.size.width-10, frame.size.height-12)];
        _hideLabel.backgroundColor = [UIColor whiteColor];


        [self addSubview:_textField];
        [self addSubview:_hideLabel];

        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textFieldDidChange:) name:UITextFieldTextDidChangeNotification object:nil];

    }
    return self;
}

当收到 UITextFieldTextDidChangeNotification 时，隐藏除最后一个字符之外的所有字符。隐藏文本将以编程方式在 UILabel 上设置。此外，安排一个将隐藏最后一个字符的计时器。如果键入更多文本，则此计时器无效。

- (void)textFieldDidChange:(NSNotification*)notification
{
    UITextField* textField = notification.object;
    if (textField == _textField)
    {
        NSString* text = textField.text;


        [self hideExceptLastCharacter:text];

        [self.hideTimer invalidate];
        self.hideTimer = [NSTimer scheduledTimerWithTimeInterval:1
                                                          target:self
                                                              selector:@selector(hideLastCharacter)
                                                    userInfo:nil
                                                     repeats:NO];


    }
}

UILabel 没有闪烁的光标。所以我们通过在'|'之间交替来模拟它和一个空间。闪烁的光标在编辑开始时放置，在编辑结束时移除。

- (void)textFieldDidBeginEditing:(UITextField *)textField
{
    if (_hideLabel.text == nil)
    {
        _hideLabel.text =  @"|";
    }
    else
    {
        _hideLabel.text =  [_hideLabel.text stringByAppendingString:@"|"];
    }

    self.blinkTimer = [NSTimer scheduledTimerWithTimeInterval:0.5 target:self selector:@selector(blinkCursor) userInfo:nil repeats:YES];
}

- (void)textFieldDidEndEditing:(UITextField *)textField
{
    NSRange range;

    range.location = _hideLabel.text.length - 1;
    range.length = 1;

    _hideLabel.text = [_hideLabel.text stringByReplacingCharactersInRange:range withString:@""];

    [_blinkTimer invalidate];
}

- (void)blinkCursor
{
    if (_hideLabel.text.length > 0)
    {
        static BOOL visible = YES;

        NSRange range;
        range.location = _hideLabel.text.length - 1;
        range.length = 1;

        if (visible)
        {
            _hideLabel.text = [_hideLabel.text stringByReplacingCharactersInRange:range withString:@" "];
        }
        else
        {
            _hideLabel.text = [_hideLabel.text stringByReplacingCharactersInRange:range withString:@"|"];
        }
        visible = !visible;
    }
}

除了最后一个字符之外的字符被隐藏。这是在 UILabel 上设置的。 UITextField 保持不变。

- (void)hideExceptLastCharacter:(NSString*)string
{
    int length = [_textField.text length];

    NSString* s = @"";
    for (int i = 0; i < length-1; i++)
    {
        s = [s stringByAppendingString:@"●"];
    }

    if (_textField.text.length > 0)
    {
        _hideLabel.text = [s stringByAppendingString:[_textField.text substringFromIndex:_textField.text.length-1]];
        _hideLabel.text = [_hideLabel.text stringByAppendingString:@"|"];
    }
    else
    {
        _hideLabel.text = @"|";
    }
}

- (void)hideLastCharacter
{
    if (_hideLabel.text.length > 1)
    {
        NSRange range;
        range.location = [_hideLabel.text length]-2;
        range.length = 1;

        _hideLabel.text = [_hideLabel.text stringByReplacingCharactersInRange:range withString:@"●"];
    }
}

- (void)dealloc
{
    [_hideTimer invalidate];
    [_blinkTimer invalidate];
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}

@end

请参阅此Github project 以供参考。

Answer 3

优化@lonlywolf 答案以获得更好的性能代码： 仅优化了两个循环的方法，当输入超过 30 个符号时会减慢程序速度

- (void)hideTextInTextFieldExceptOne:(NSString *)string
{
    int lenght = [passwordTextField.text length];
    if (lenght -1 > 0) {
        NSString *resultString = @"";
        for (int i = 0; i < lenght-1; i++)
        {
            resultString = [resultString stringByAppendingFormat:@"*"];
        }
        NSRange range = NSMakeRange(0, lenght - 1);
        passwordTextField.text = [fieldPassword.text stringByReplacingCharactersInRange:range withString:resultString];
    }
}

- (void)hideTextInTextField
{
    int lenght = [passwordTextField.text length];
    if (lenght > 0) {
        NSString *resultString = @"";
        for (int i = 0; i < lenght; i++)
        {
            resultString = [resultString stringByAppendingFormat:@"*"];
        }
        passwordTextField.text = resultString;
    }
}