About #selector and MVC - ios

Question

What I have:
four TableViewController(A, B, C, D) - which would show four category
of content.
fake TabBarController based on UITabBarController, it
works fine.
What I want to do:
Add a button on ATableView, and it will use a method on my FakeTabBarController (because I want to share the method so I can use it on BTableViewController, CTableViewController rather than duplicate it two or three times)
So I just make the method public (on the .h file), and included the .h file in my ATableViewController. Then,
addTarget:action:forControlEvents: as always, but.. it doesn't work, please help!
Error:
[ATableViewController assisitantButtonPressed:]: unrecognized selector sent to instance 0x715a8d0
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[ATableViewController assisitantButtonPressed:]: unrecognized selector sent to instance 0x715a8d0'
*** First throw call stack:
(0x1ca1012 0x10dee7e 0x1d2c4bd 0x1c90bbc 0x1c9094e 0x10f2705 0x262c0 0x26258 0xe7021 0xe757f 0xe66e8 0x2ea1d3 0x1c69afe 0x1c69a3d 0x1c477c2 0x1c46f44 0x1c46e1b 0x1bfb7e3 0x1bfb668 0x22ffc 0x1c8d 0x1bb5)
libc++abi.dylib: terminate called throwing an exception
FakeTabBarController.h:
#import <UIKit/UIKit.h>
#interface CustomTabBarController : UITabBarController
- (IBAction)assisitantButtonPressed:(UIButton *)sender;
#end
FakeTabBarController.m:
...
- (IBAction)assisitantButtonPressed:(UIButton *)sender
{
switch ([sender tag]) {
case 0: // AA
NSLog(#"AA");
break;
case 1: // BB
NSLog(#"BB");
break;
default:
break;
}
}
...
ATableViewController.m:
#import "ATableViewController.h"
#import "ATableCell.h"
#import "FakeTabBarController.h"
...
- (void)viewDidLoad
{
[super viewDidLoad];
UIImage *AAImage = [UIImage imageNamed:#"search.png"];
UIButton *AAButton = [[UIButton alloc] initWithFrame:CGRectMake(self.view.frame.size.width * 0.73, 0, AAImage.size.width, AAImage.size.height)];
[AAButton setTag:0];
[AAButton setImage:searchImage forState:UIControlStateNormal];
[AAButton addTarget:self action:#selector(assisitantButtonPressed:) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:AAButton];
}

Answer 1

This line
[AAButton addTarget:self action:#selector(assisitantButtonPressed:) forControlEvents:UIControlEventTouchUpInside];
sets the target to method assisitantButtonPressed: of self, which is ATableViewController. It throws exception because ATableViewController doesn't have that method. The correct way is to add a weak property to ATableViewController to keep a reference to CustomTabBarController and addTarget to that TabBar, rather than self
#interface ATableViewController
#property (weak, nonatomic) CustomTabBarController* tabBar;
...
#end
#implementation ATableViewController
-(void)viewDidLoad {
[super viewDidLoad];
self.tabBar = <you must somehow obtain the tab bar reference, either here or in init>
...
[AAButton addTarget:self.tabBar action:#selector(assisitantButtonPressed:) forControlEvents:UIControlEventTouchUpInside];
...
}
#end
It's good that you're trying to avoid code duplication. However since ATableViewController, BTableViewController, ... are very similar (judging from your question and their naming), you may want to use just one single TableViewController but with different actual data. Besides, if the method assisitantButtonPressed: really belongs to the table view controller and you moved it to the navBar just to avoid code duplication, it is a very bad practice.