How to Control UISearchBar Background Color

When you have a list, you want to search it. How would you do that? No, don't code it by yourself. Done it, removed it.

By default each UITableView comes with search support via a built-in UISearchDisplayController. You just add and connect UISearchBar to your table in Interface Builder and provide some delegate methods to make it work. Pretty easy:

self.searchDisplayController.delegate =
self.searchDisplayController.searchBar.delegate =
self.searchDisplayController.searchResultsDataSource =
self.searchDisplayController.searchResultsDelegate = self.mySearchObject;

Controlling how your UISearchBar looks like is a bit more difficult. If you want to show search box and some other component(s) side by side, you can do it by putting UIToolbar at back and a short UISearchBar on top of it. By default their backgrounds are different, looking pretty ugly together. Like a hack, what it really is.

You can fix that by doing two things. First get rid of default background:

for (UIView *view in self.searchBar.subviews)
{
   if ([view isKindOfClass:NSClassFromString
     (@"UISearchBarBackground")])
   {
     [view removeFromSuperview];
     break;
   }
}

...and the second thing? Something that will be extremely hard to find out, unless you get it right by accident? You have to set UISearchBar style Black Translucent!

Sad to think how many hours I wasted experimenting Things That Will Not Work, just to find out that kind of miniscule solution. Also bet that this will not work one year from now...

How to Disable UITabBarItems but Only Temporarily

User is allowed to use only one UITabBar item, until he has done something e.g. made a selection on list. Other tabs are available after that. Access to tabs can be blocked again e.g. if user chooses to delete current "entry".

Tab access control is done in AppDelegate, since it owns UITabBarController and UITabBarItems. Just set up delegate handling - and that's the key: either there is a delegate to block tabs or there is none for free access:

@interface MyAppDelegate : NSObject <UIApplicationDelegate, UITabBarControllerDelegate>
{
   UITabBarController *tabBarController;
}
...
- (BOOL)tabBarController:(UITabBarController *)aTabBarController
shouldSelectViewController:(UIViewController *)viewController
{
  if (
    ([aTabBarController.viewControllers objectAtIndex:1] == viewController) ||
    ([aTabBarController.viewControllers objectAtIndex:2] == viewController)
  )
  {
    // Disable switch to tab 1 and 2
    // Check: otherViewController to enable
    // Check: SomeViewObject to disable
    return NO;
  }
  else
  {
    // Tab ok at index 0
    return YES;
  }
}

Access control can be enabled in any other class/file:

- (void)blockTabAccess
{
  MyAppDelegate *app = (MyAppDelegate *)[[UIApplication sharedApplication] delegate];
  app.tabBarController.delegate = app;
  [app SwitchToTab:kTabFirst];
}

Access control can be disabled in any other class/file:

- (void)releaseTabAccess
{
  MyAppDelegate *app = (MyAppDelegate *)[[UIApplication sharedApplication] delegate];
  app.tabBarController.delegate = nil;
  [app SwitchToTab:kTabSecond];
}

Some consider it poor design to access AppDelegate directly from "anywhere" and further more to use it to control application state. My defense are the classic a) it's easy b) it's fast c) it works and d) sometimes central control place is a good thing.

Btw this works only as long as you don't need UITabBarControllerDelegate for any other purpose. You have been warned.

Class does not implement the 'NSStreamDelegate' protocol

Got this warning after upgrading to Xcode 3.2.3. To fix it add NSStreamDelegate into your class interface:

@interface MyClass: NSObject {}
@interface MyClass: NSObject <NSStreamDelegate> {}

NSStreamDelegate is defined for Cocoa, but not Cocoa Touch. iPhone stream:handleEvent: is an informal delegate method.

On Mac OS X 10.6 SDK (used by iPhone OS 4) delegate methods are generally defined in formal protocols rather than informal protocols as before, which means you have to declare the protocol conformance in the class interface of the delegate. More info at Mac OS X SDK release notes.

How to Create Custom Map Annotation Button

Custom accessory button for MKPinAnnotationView right side, create inside MKMapViewDelegate protocol mapView:viewForAnnotation method:

UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, 20, 20)];
[button setImage:[UIImage imageNamed:@"myButton.png"] forState:UIControlStateNormal]; 
view.rightCalloutAccessoryView = button;

Usually sample codes use UIButtonTypeDetailDisclosure as right button, but you can't use that unless you really show additional details. For anything else, you must use a custom button.

How to Create Delayed Tab Change

Not sure, if it's a good idea, but this is how you create "smooth" tab view changes:

#pragma mark - TabBar controller delegate
- (void)tabBarController:(UITabBarController*)tbc
  didSelectViewController:(UIViewController*)newSelection
{
    [UIView beginAnimations:@"myTabFade" context:nil];
    [UIView setAnimationDuration:0.5];
    for (UIViewController* vc in tbc.viewControllers)
        vc.view.alpha = (vc==newSelection) ? 1 : 0;
    [UIView commitAnimations];  
}

User will notice something happened as expected and your app will look either stylish or slow, depending on your graphics, UI design and overall implementation.

Be careful, style is not an easy thing to achieve!