Get keyboard height from an NSNotification

(deprecated)UINotificationKeyboardHeight.m

@implementation NSNotification (KeyboardHeight)

- (CGFloat)keyboardHeight {
    CGRect bounds;
    NSValue *boundsValue = [self.userInfo objectForKey:UIKeyboardBoundsUserInfoKey];
    if (boundsValue) {
        [boundsValue getValue:&bounds];
        return bounds.size.height;
    } else {
        return 0;
    }
}

@end

UINotification+KeyboardHeight.m

@implementation NSNotification (KeyboardHeight)

- (CGFloat)keyboardHeight {
    CGRect bounds;
    NSValue *boundsValue = [self.userInfo objectForKey:UIKeyboardBoundsUserInfoKey];
    if (boundsValue) {
        [boundsValue getValue:&bounds];
        return bounds.size.height;
    } else {
        return 0;
    }
}

@end

UINotificationKeyboardHeight.m

@implementation NSNotification (KeyboardHeight)

- (CGFloat)keyboardHeight {
    CGRect startFrame;
    NSValue *startFrameValue = [self.userInfo objectForKey:UIKeyboardFrameBeginUserInfoKey];
    if (startFrameValue) {
        [startFrameValue getValue:&startFrame];
        return startFrame.size.height;
    } else {
        return 0;
    }
}

@end