objective-c - 键盘更改时是否会发送任何通知(例如从 NumberPad 到 Default)

Question

我正在尝试了解如何在键盘更改时收到通知。我想做的是在类型 4 和 5(NumberPad 和 PhonePad)的键盘上添加一个 DONE 按钮，一切正常，除了当我使用默认 KB 类型从 TextField 转换时，通知 KeyboardDidAppear 不是被解雇。

这是我得到的:

- (void)viewDidLoad
{
    [super viewDidLoad];

    [[NSNotificationCenter defaultCenter] addObserver:self 
                                             selector:@selector(keyboardDidShow:) 
                                                 name:UIKeyboardDidShowNotification 
                                               object:nil]; 

}

然后我为当前 KB 类型和当前正在编辑的 TextField 添加了一个属性:

#pragma mark - Delegate Methods
-(BOOL)textFieldShouldBeginEditing:(UITextField *)textField {
    self.currentKBType = textField.keyboardType;
    self.curTextField = textField;
    return YES;
}

然后我根据当前知识库类型决定是否添加那个 DONE 按钮:

- (void)keyboardDidShow:(NSNotification *)note {
    if (self.currentKBType == 4 || self.currentKBType == 5) {
        [self addButtonToKeyboard];
    }
}

问题是通知会在键盘显示时触发，但不会在键盘更改时触发(从一个 TextField 转换到另一个指定不同 KB 类型的 TextField。

有什么建议吗？我错过了什么吗？

Answer 1

明白了。有点逻辑，但它完美无缺。这是我所做的:添加私有(private)属性:

@property (nonatomic) UIKeyboardType currentKBType;
@property(nonatomic,strong) UITextField *curTextField;
@property(nonatomic,strong) UIButton *doneButton;
@property(nonatomic) BOOL doneButtonDisplayed;

然后在两个 TextField 委托(delegate)方法中添加以下逻辑:

-(BOOL)textFieldShouldBeginEditing:(UITextField *)textField {
    self.currentKBType = textField.keyboardType;
    if (textField.keyboardType == 4 || textField.keyboardType == 5) {
        if (!doneButtonDisplayed) {
            [self addButtonToKeyboard];
        }
    } else {
        if (doneButtonDisplayed) {
            [self removeButtonFromKeyboard];
        }
    }

    self.curTextField = textField;
    return YES;
}

在我在 viewDidLoad 中注册 VC 的 KeyboardDidShowNotification 中:

- (void)keyboardDidShow:(NSNotification *)note {
    if (self.currentKBType == 4 || self.currentKBType == 5) {
        if (!doneButtonDisplayed) {
            [self addButtonToKeyboard];
        }
    } else {
        if (doneButtonDisplayed) {
            [self removeButtonFromKeyboard];
        }
    }
}

以及这些方法中引用的两个方法:

- (void)addButtonToKeyboard {

    // create custom button
    doneButton = [UIButton buttonWithType:UIButtonTypeCustom];
    doneButton.frame = CGRectMake(0, 163, 106, 53);
    doneButton.adjustsImageWhenHighlighted = NO;

    [doneButton setImage:[UIImage imageNamed:@"DoneNormal.png"] forState:UIControlStateNormal];
    [doneButton setImage:[UIImage imageNamed:@"DoneHL.png"] forState:UIControlStateHighlighted];

    [doneButton addTarget:self action:@selector(resignKeyboard) forControlEvents:UIControlEventTouchUpInside];
    // locate keyboard view
    if ([[[UIApplication sharedApplication] windows] count] > 1) {
        UIWindow* tempWindow = [[[UIApplication sharedApplication] windows] objectAtIndex:1];
        UIView* keyboard;
        for(int i=0; i<[tempWindow.subviews count]; i++) {
            keyboard = [tempWindow.subviews objectAtIndex:i];
            // keyboard found, add the button
            if([[keyboard description] hasPrefix:@"<UIPeripheralHost"] == YES) {
                [keyboard addSubview:doneButton];
                self.doneButtonDisplayed = YES;
            }
        }

    }
}

- (void)removeButtonFromKeyboard {  
    [doneButton removeFromSuperview];
    self.doneButtonDisplayed = NO;
}

最后，每当触摸“完成”按钮时调用 resignKeyboard 方法:

-(void)resignKeyboard {
    [self.curTextField resignFirstResponder];
    self.doneButtonDisplayed = NO;
}

这将在显示 NumberPad 或 PhonePad 类型的键盘时添加完成按钮，并将它从其他键盘类型中删除(仅当已添加时)。

经过测试，效果很好。