cannot remove UIButton from keyboard

I am using a numberkeyboard, and I am adding a done key to the bottem left corner. I want to remove this button from the keyboard because later I want to use a regular keyboard, and the done button is still showing up. I am globally declaring the UIButton and calling removeFromSuperview on it. Nothing happens. Also, if I call removeFromSuperview in the same method as it is added, it successfully removes the button. Here is some code.

-(void)addHideKeyboardButtonToKeyboard{


// Locate non-UIWindow.
keyboardWindow=nil;
for (UIWindow *testWindow in [[UIApplication sharedApplication] windows]) {
    if (![[testWindow class] isEqual:[UIWindow class]]) {
        keyboardWindow = testWindow;
        break;
    }
}
if (!keyboardWindow) return;

// Locate UIKeyboard.  
UIView *foundKeyboard = nil;
for (UIView *possibleKeyboard in [keyboardWindow subviews])开发者_如何学JAVA {

    // iOS 4 sticks the UIKeyboard inside a UIPeripheralHostView.
    if ([[possibleKeyboard description] hasPrefix:@"<UIPeripheralHostView"]) {
        possibleKeyboard = [[possibleKeyboard subviews] objectAtIndex:0];
    }                                                                                

    if ([[possibleKeyboard description] hasPrefix:@"<UIKeyboard"]) {
        foundKeyboard = possibleKeyboard;
        break;
    }
}

if (foundKeyboard) {
    // create custom button
    NSString *deviceType = [UIDevice currentDevice].model;
    if(!([deviceType isEqualToString:@"iPad"] || [deviceType isEqualToString:@"iPad Simulator" ]))
    {
        doneButton = [UIButton buttonWithType:UIButtonTypeCustom];
        doneButton.frame = CGRectMake(0, 163, 106, 53);
        doneButton.adjustsImageWhenHighlighted = NO;
        [doneButton setImage:[UIImage imageNamed:@"doneup.png"] forState:UIControlStateNormal];
        [doneButton setImage:[UIImage imageNamed:@"donedown.png"] forState:UIControlStateHighlighted];
        [doneButton addTarget:self action:@selector(textFieldShouldReturn:) forControlEvents:UIControlEventTouchUpInside];
        [foundKeyboard addSubview:doneButton];
    }
}
}

and to remove the doneButton

- (BOOL)textFieldShouldReturn:(UITextField *)textField
  { 
       [doneButton removeFromSuperView]; 
  } 

A viable option would be to set doneButton to nil, then realloc and initialize it whenever it's needed...not quite as easy as the faulty removeFromSuperview:, but an option nonetheless. Correct me if I'm wrong because I believe the method I suggested may cause a memory leak.

addHideKeyboard was a selector being added to the NSNotificationCenter, which means every time the keyboard showed up, it would re-add the done button.

Since you have done it via NotificationCenter, you need to remove the observer when moving out of this viewController (may be before loading a new ViewController or dismissing current controller.)

So let's say that you have added this NotificationCenter in ViewDidLoad of your xxxViewController that needs the "Done button".

[[NSNotificationCenter defaultCenter] addObserver:selfselector:@selector(addHideKeyboardButtonToKeyboard:)
                                             name:UIKeyboardWillShowNotification
                                           object:nil];

Now, once you move to yyyViewController somewhere like this, then remove the observer first.

-(void)showNewViewController {

 // remove the notification observer
 [[NSNotificationCenter defaultCenter] removeObserver:self
                                                 name:UIKeyboardWillShowNotification
                                               object:nil];

 yyyViewController *vctrllr = [[yyyViewController alloc] init];
 ...
 ...
}

I know, its a kind of history question, but it got my attention on this, only now.