I'm trying to provide an IBAction
method for common functionality that is required at various parts of the app.
i.e. Login is implemented modally, and if it succeeds results in a notification that allows all loaded view controllers to react to this event (transition from anonymous to authenticated)
@interface MyAppDelegate : NSObject <UIApplicationDelegate>
{
...
}
- (IBAction)loginTapped:(id)sender;
@end
I set the action of that button to the First Responder in IB, however the responder chain doesn't give MyAppDelegate
a chance to respond.
My problem is that, I don't want to replicate the method at various parts of the responder chain, I would like to add it to a common class that is already a subclass.
The UIResponder
chain goes all the way through to the UIApplication
but that seems to be the end. My UIApplicationDelegate
doesn't get to participate.
I want to insert or add my app delegate to the responder chain!
(or find another way to hook up the UIButton
touch-up-inside to an app-wide implementation.. I want to avoid subclassing the UITabBarController
or UIWindow
if possible)
You could subclass UIApplication
to have -nextResponder
return the application delegate if it is a UIResponder
subclass. You'll then need to alter your call to UIApplicationMain
to use your custom subclass.
I haven't tried this myself, but I can't think of any immediate problems this would cause.
Starting with iOS 5, the AppDelegate is automatically the last link in the responder chain. Xcode project templates will create an AppDelegate that is a subclass of UIResponder
rather than NSObject
. However, to avoid cluttering up the AppDelegate, override the AppDelegate's nextResponder
and offload work into a custom UIResponder
object:
- (UIResponder *)nextResponder
{
static dispatch_once_t onceToken;
static LastUIResponder *lastResponder = nil;
dispatch_once(&onceToken, ^{
lastResponder = [[LastUIResponder alloc] init];
});
return lastResponder;
}
来源:https://stackoverflow.com/questions/3356863/how-do-i-add-the-uiapplicationdelegate-to-the-end-of-the-uiresponder-chain