UIActionSheet’s cancel button presses not detected properly

Last night I came across a really annoying bug with UIActionSheet when used in conjunction with a UITabBarController.

Basically there is a killer bug which means you can’t click the Cancel button on a UIActionSheet and forces the user to either close the App or use one of the destructive action buttons to get rid of the alert.

It appears to be a changed from OS <= 2.1 to >= 2.2. In iPhone OS 2.1 and earlier, the UIActionSheet comes up from the top of the tab bar, but in 2.2, it comes up from the bottom of the tab bar, and thus covers the tab view but the tab view still takes focus. If you try to press the cancel button below the top of the tab bar (barely visible through the semi-transparent UIActionSheet), the press does not register. If you click above the underlying tab bar, the press does work.

This is how you fix it.

1) In your AppDelegate.h function

+ (UITabBarController *)tabbarController;

Note that tabbarController should be different than your ACTUAL UITabBarController name.

Next edit your AppDelegate.m functiuon and above your @implementation

static AppDelegate *s_appdelegate = nil;

@implementation AppDelegate

Inside applicationDidFinishLaunching add

s_appdelegate = self;

At the bottom of AppDelegate.m before @end add

+ (UITabBarController *)tabbarController
{
	return s_appdelegate ? s_appdelegate.tabBarController : nil;
}

Finally in your child view in which you wish to display your UIActionSheet add

	UIActionSheet *sheet = [[UIActionSheet alloc] initWithTitle:@"Delete?"
		delegate:self cancelButtonTitle:@"Cancel" destructiveButtonTitle:@"Yes" otherButtonTitles:nil, nil];

	UIView *viewBase = self.view;
	viewBase = [[AppDelegate tabbarController] view];
	[sheet showInView:viewBase];
	[sheet release];