Programmatically align a toolbar on top of the iPhone keyboard

user_24213 0
Viewed 68914

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 programmatically determine the position of the keyboard in relation to the current view?

keyboard iphone cocoa-touch ios
7 Answers

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];
Admin1

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

See the UIWindow class reference.

user_44680

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.

user_1985140

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.

user_10430
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