如何在UITextField子類中正確添加addObserver以便在鍵盤可見時進行獲取？

我有UITextField的子類。我想知道鍵盤何時可見。如果鍵盤隱藏我的文本字段，這將幫助我移動所有視圖。如何在UITextField子類中正確添加addObserver以便在鍵盤可見時進行獲取？

在我的子類，我想補充觀察員如下：

- (id)initWithCoder:(NSCoder *)aDecoder{ 
    if (self = [super initWithCoder:aDecoder]) { 
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardIsVisible:) name:UIKeyboardDidShowNotification object:nil]; 
    } 
    return self; 
}

我希望能趕上鍵盤的大小：

/* Get height when keyboard is visible */ 
- (void)keyboardIsVisible:(NSNotification*)notification 
{ 
    NSDictionary* keyboardInfo = [notification userInfo]; 
    NSValue* keyboardFrameBegin = [keyboardInfo valueForKey:UIKeyboardFrameBeginUserInfoKey]; 
    CGRect keyboardFrameBeginRect = [keyboardFrameBegin CGRectValue]; 

    _keyboardHeight =keyboardFrameBeginRect.size.height; 

}

我會用伊娃_keyboardHeight來決定，如果我有移動鍵盤：

/* Move keyboard */ 
-(void)showKeyboardWithMove { 

    CGRect screenRect = [[UIScreen mainScreen] bounds]; 
    ////CGFloat screenWidth = screenRect.size.width; 
    CGFloat screenHeight = screenRect.size.height; 


    if (self.frame.origin.y + self.frame.size.height > screenHeight - _keyboardHeight) { 
     double offset = screenHeight - _keyboardHeight - self.frame.origin.y - self.frame.size.height; 
     CGRect rect = CGRectMake(0, offset, self.superview.frame.size.width, self.superview.frame.size.height); 

     [UIView beginAnimations:nil context:NULL]; 
     [UIView setAnimationDuration:0.3]; 

     self.superview.frame = rect; 

     [UIView commitAnimations]; 
    } 

}

從我的視圖控制器類我呼籲showKeyboardWithMove：

- (void)textFieldDidBeginEditing:(MyCustomTextField *)textField 
{ 
    // Call method for moving control when Keyboard is shown and hides it 
    [textField showKeyboardWithMove]; 
} 

- (void)textFieldDidEndEditing:(MyCustomTextField *)textField 
{ 
    // Call method for returning control when Keyboard is hidden 
    [textField hideKeyboardWithMove]; 
}

問題是，當我第一次顯示鍵盤時，keyboardIsVisible不起火。所以我認爲我的觀察員沒有正確編碼。有任何想法嗎？

來源

2014-10-02 new2ios

的可能的複製[如何使一個的UITextField向上移動時，鍵盤的存在（http://stackoverflow.com/questions/1126726/how-to-make-a-uitextfield-move-up-when -keyboard-is-present） – PAC 2016-02-16 07:20:27

嘗試刪除您

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

到viewWillAppear中。在我的情況下，它的作品。我也用

UIKeyboardWillShowNotification

，而不是

UIKeyboardDidShowNotification

來源

2014-10-02 08:44:37

它不起作用。當我將'addObserver'移動到'viewWillAppear'時，觀察者根本沒有設置。 – new2ios 2014-10-02 09:00:40

在Objective-C

要移動視圖時，當鍵盤是可見可通過多種方式來完成，看到這個link

In Swift：

添加以下兩個d首先在viewDidLoad（）函數中定義：

NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name: UIKeyboardWillShowNotification, object: nil) 

NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name: UIKeyboardWillHideNotification, object: nil)

然後在您的類中添加以下兩種方法。

func keyboardWillShow(notification: NSNotification) {  
    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() { 
     self.view.frame.size.height -= keyboardSize.height 
    } 

} 

func keyboardWillHide(notification: NSNotification) { 
    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() { 
     self.view.frame.size.height += keyboardSize.height 
    } 
}

來源

2016-02-16 07:06:51 PAC

如何在UITextField子類中正確添加addObserver以便在鍵盤可見時進行獲取？

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