iOS virtual keyboard size without notification center - ios

Question

I need to scroll up my scrollView, when textFiewl is tapped that is bellow the virtual keyboard. I call [self.scrollView setContentOffset:scrollPoint animated:YES];. To get the screen's visible area, i obviously need the KB size.
I am familiar with
NSDictionary *info = [notification userInfo];
CGSize kbSize = [self.view convertRect:
[info[UIKeyboardFrameBeginUserInfoKey] CGRectValue]
fromView:nil].size;
however, it doesn't work for me, because when a user taps on possibly half-hidden textfield, i don't receive the keyboard notification.
So i call the method in textFieldDidBeginEditing:, which is called before keyboard will send message, and so i don't know the KB size on first tap.
So the question is: is possible to get the KB size, without invoking corresponding notification?
Programmaticaly, not hardcoding.

Answer 1

You are doing it wrong.
You need to also listen for the keyboard show/hide notifications and then adjust your screen.
Here is a sample skeleton code:
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];
[nc addObserver:self selector:#selector(keyboardChangedStatus:) name:UIKeyboardWillShowNotification object:nil];
[nc addObserver:self selector:#selector(keyboardChangedStatus:) name:UIKeyboardWillHideNotification object:nil];
}
- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];
[nc removeObserver:self name:UIKeyboardWillShowNotification object:nil];
[nc removeObserver:self name:UIKeyboardWillHideNotification object:nil];
}
#pragma mark - Get Keyboard size
- (void)keyboardChangedStatus:(NSNotification*)notification {
//get the size!
CGRect keyboardRect;
[[[notification userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey] getValue:&keyboardRect];
keyboardHeight = keyboardRect.size.height;
//move your view to the top, to display the textfield..
[self moveView:notification keyboardHeight:keyboardHeight];
}
#pragma mark View Moving
- (void)moveView:(NSNotification *) notification keyboardHeight:(int)height{
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:0.3];
[UIView setAnimationBeginsFromCurrentState:YES];
CGRect rect = self.view.frame;
if ([[notification name] isEqual:UIKeyboardWillHideNotification]) {
// revert back to the normal state.
rect.origin.y = 0;
hasScrolledToTop = YES;
}
else {
// 1. move the view's origin up so that the text field that will be hidden come above the keyboard (you need to adjust the value here)
rect.origin.y = -height;
}
self.view.frame = rect;
[UIView commitAnimations];
}