Programatically align a toolbar on top of the iPhone keyboard

Question

In several cases I want to add a toolbar to the top of the iPhone keyboard (as in iPhone Safari when you're navigating form elements, for example).

Currently I am specifying the toolbar's rectangle with constants but because other elements of the interface are in flux - toolbars and nav bars at the top of the screen - every time we make a minor interface change, the toolbar goes out of alignment.

Is there a way to programatically determine the position of the keyboard in relation to the current view?

Answer 1

There's no way (AFAIK) to get the dimensions of the keyboard view. It is however constant, at least in every iPhone version so far.

If you calculate the toolbar position as an offset from the BOTTOM of your view, and take the size of your view into account, then you should not have to worry whether a navbar is present or not.

E.g.

#define KEYBOARD_HEIGHT 240 // example - can't remember the exact size
#define TOOLBAR_HEIGHT 30

toolBarRect.origin.y = viewRect.size.height - KEYBOARD_HEIGHT - TOOLBAR_HEIGHT;

// move toolbar either directly or with an animation

Instead of a define, you could easily create a keyboardHeight function that returns the size based on whether the keyboard is being displayed, and move this toolbar positioning into a separate function that reorganizes your layout.

Also it can depend on where you do this positioning as it's possible the size of your view may change between being loaded and shown based on your navbar setup. I believe the best place to do it would be in viewWillAppear.

Answer 2

If you register for keyboard notifications, ie UIKeyboardWillShowNotification UIKeyboardWillSHideNotification, etc, the notification you receive will contain the bounds of the keyboard in the userInfo dict (UIKeyboardBoundsUserInfoKey).

See the UIWindow class reference.

Answer 3

So basically:

In the init method:

NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];
[nc addObserver:self selector:@selector(keyboardWillShow:) name: UIKeyboardWillShowNotification object:nil];
[nc addObserver:self selector:@selector(keyboardWillHide:) name: UIKeyboardWillHideNotification object:nil];

And then have methods referred to above to adjust the position of the bar:

-(void) keyboardWillShow:(NSNotification *) note
{
    CGRect r  = bar.frame, t;
    [[note.userInfo valueForKey:UIKeyboardBoundsUserInfoKey] getValue: &t];
    r.origin.y -=  t.size.height;
    bar.frame = r;
}

Could make it pretty by animating the position change by wrapping it in

    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.3];
//...
    [UIView commitAnimations];

Answer 4

Thanks for the responses. I am using essentially the same technique shown above by Josh, and it looks exactly the same as it would if I'd been able to make the bar a subview of the keyboard (but it requires more code).

Answer 5

the code work tool bar h41 keyboard h 216

can u do the calculation with n if n else so the tool bar follow the keyboard n view position on screen

Answer 6

In 3.0 and above you can get the animation duration and curve from the userInfo dictionary of the notifications.

for instance, to animate the size of the view to make room for the keyboard, register for the UIKeyboardWillShowNotification and do something like the following:

- (void)keyboardWillShow:(NSNotification *)notification
{
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationCurve:[[[notification userInfo] objectForKey:UIKeyboardAnimationCurveUserInfoKey] intValue]];
    [UIView setAnimationDuration:[[[notification userInfo] objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue]];

    CGRect frame = self.view.frame;
    frame.size.height -= [[[notification userInfo] objectForKey:UIKeyboardBoundsUserInfoKey] CGRectValue].size.height;
    self.view.frame = frame;

    [UIView commitAnimations];
}

Do a similar animation for UIKeyboardWillHideNotification.

Answer 7

As of iOS 3.2 there's a new way to achieve this effect.

UITextFields and UITextViews have an inputAccessory property, which you can set to any view, that is automatically displayed above and animated with the keyboard.

Note that the view you use should neither be in the view hierarchy elsewhere, nor should you add it to some superview, this is done for you.