Call AppDelegate Method From Subclass?

Question

I'm probably not explaining this logically, as I'm new to Objective-C, but here I go...

I am writing an application in Objective-C that interacts with a WebView. Part of the app involves sharing an image via NSSharingService that is currently displayed in the WebView. Consequently, I have a method like this defined in my AppDelegate.m file:

#import "CCAppDelegate.h" #import <WebKit/WebKit.h> #import <AppKit/AppKit.h> @implementation CCAppDelegate -(void)shareFromMenu:(id)sender shareType:(NSString *)type{ NSString *string = [NSString stringWithFormat: @"window.function('%@')", type]; [self.webView stringByEvaluatingJavaScriptFromString: string]; } @end

I then have a subclass of NSMenu, defined in CCShareMenu.m, which creates a menu of available sharing options:

#import "CCShareMenu.h" @implementation CCShareMenu - (void)awakeFromNib{ [self setDelegate:self]; } - (IBAction)shareFromService:(id)sender { NSLog(@"%@", [sender title]); // [CCAppDelegate shareFromMenu]; } - (void)menuWillOpen:(NSMenu *)menu{ [self removeAllItems]; NSArray *shareServicesForItems = @[ [NSSharingService sharingServiceNamed:NSSharingServiceNameComposeMessage], [NSSharingService sharingServiceNamed:NSSharingServiceNameComposeEmail], [NSSharingService sharingServiceNamed:NSSharingServiceNamePostOnFacebook], [NSSharingService sharingServiceNamed:NSSharingServiceNamePostOnTwitter] ]; for (NSSharingService *service in shareServicesForItems) { NSMenuItem *item = [[NSMenuItem alloc] init]; [item setRepresentedObject:service]; [item setImage:[service image]]; [item setTitle:[service title]]; [item setTarget:self]; [item setAction:@selector(shareFromService:)]; [self addItem:item]; } } @end

These methods both work fine on their own, except I need to call the shareFromMenu method from within the shareFromService IBAction.

I attempted moving the IBAction method to AppDelegate.m, then realized that made zero sense as the menuWillOpen-created selectors would never find the correct methods. Similarly, I tried following the instructions posted here, but:

[CCAppDelegate shareFromMenu];

Also responded with an error saying that the method was not found.

I realize I'm doing something fundamentally wrong here, so guidance would be appreciated.

CyberMoai · Accepted Answer · 2014-05-12 02:50:49Z

1

-[CCAppDelegate shareFromMenu]

is different from

-[CCAppDelegate shareFromMenu:shareType:]

I would try adding the following to CCAppDelegate.h between @interface and @end:

-(void)shareFromMenu:(id)sender shareType:(NSString *)type

Then change your shareFromService: method to something like:

- (IBAction)shareFromService:(id)sender { NSString *shareType = @"Set your share type string here."; CCAppDelegate *appDelegate = (CCAppDelegate *)[[UIApplication sharedApplication] delegate]; [appDelegate shareFromMenu:sender shareType:shareType]; }

answered May 12, 2014 at 2:50

CyberMoai

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5 Comments

Charlie Over a year ago

My fault on forgetting the parameter in the method; I neglected to copy and paste everything. Adding the void in the header file worked however, can you explain why though?

CyberMoai Over a year ago

Methods declared in the header file are public and therefore accessible to other classes that import said file. Methods declared in the implementation files are private to that class.

Charlie Over a year ago

Are they even private if instead of using a - sign I use a + sign? - void() vs + void()?

CyberMoai Over a year ago

That is correct. + denotes a class method while - denotes an instance method. They have nothing to do with scope. See also this question and this tutorial.

Charlie Over a year ago

I see. I was getting that confused from reading this answer incorrectly. Thanks for the help.

boycechang · Accepted Answer · 2014-05-12 04:00:36Z

-(void)shareFromMenu is a member method, but

[CCAppDelegate shareFromMenu]

is calling a class function which is not the correct way to call a member function.

You may try to get the CCAppDelegate instance and then call the function like this

CCAppDelegate *appDelegate = [[UIApplication sharedApplication] delegate]; [appDelegate shareFromMenu];

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