Disabling keys on keyboard

Question

I am new to Objective-C, and I am looking to limit a user from switching from the alphabet portion of a normal keyboard to the numeric/punctuation side. This being said, I would like to disable the button on the keyboard that does the switch. Maybe I'm putting in the wrong search parameters, but I'm finding little on Google and even less in my reference books. How would I go about actually disabling a button on an iOS keyboard? With alpha/numeric/punctuation characters this would be easily done by just ignoring the inputed characters that were entered, but the button that switches between keyboard portions does an action as opposed to returning a character.

Thank you for your help!

Answer 1

You actually can add and remove buttons of the default UIKeyboard

There's some recipes on the Internet like this: http://www.iphonedevsdk.com/forum/iphone-sdk-development/6573-howto-customize-uikeyboard.html and like this: http://www.iphonedevsdk.com/forum/iphone-sdk-development/6275-add-toolbar-top-keyboard.html

Those posts show you how to add a button, however the same principle can be used to remove.

Below I'll show you a compilation of one of the solutions:

//The UIWindow that contains the keyboard view - 
//It some situations it will be better to actually
//iterate through each window to figure out where the keyboard is, 
// but In my applications case
//I know that the second window has the keyboard so I just reference it directly
//
UIWindow* tempWindow = [[[UIApplication sharedApplication] windows] 
//                     objectAtIndex:1];

//Because we cant get access to the UIKeyboard throught the SDK we will 
// just use UIView. 
//UIKeyboard is a subclass of UIView anyways
UIView* keyboard;

//Iterate though each view inside of the selected Window
for(int i = 0; i < [tempWindow.subviews count]; i++)
{
    //Get a reference of the current view 
    keyboard = [tempWindow.subviews objectAtIndex:i];

    //Check to see if the className of the view we have 
    //referenced is "UIKeyboard" if so then we found
    //the keyboard view that we were looking for
    if([[keyboard description] hasPrefix:@"<UIKeyboard"] == YES)
    {
        // Keyboard is now a UIView reference to the 
        // UIKeyboard we want. From here we can add a subview
        // to th keyboard like a new button

        //Do what ever you want to do to your keyboard here...
    }
}