Question

Just beginning iOS development and I am getting a crash on creating an UITabBarController with a TableViewController in tab 1 (2nd tab).

Here is my code – AppDelegate.m:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 
{
diseases = [NSMutableArray arrayWithCapacity:5];
        Disease *disease1 = [[Disease alloc] init];
        Disease *disease2 = [[Disease alloc] init];
        Disease *disease3 = [[Disease alloc] init];
        Disease *disease4 = [[Disease alloc] init];
        Disease *disease5 = [[Disease alloc] init];

        disease1.name = @"disease1";
        disease2.name = @"disease2";
        disease3.name = @"disease3";
        disease4.name = @"disease4";
        disease5.name = @"disease5";

        [diseases addObject:disease1];
        [diseases addObject:disease2];
        [diseases addObject:disease3];
        [diseases addObject:disease4];
        [diseases addObject:disease5];


UITabBarController *tabBarController = (UITabBarController *)self.window.rootViewController;

UINavigationController *navigationController = 
[[tabBarController viewControllers] objectAtIndex:0];

FirstViewController *firstViewController = [[FirstViewController alloc] initWithNibName:@"NormalBiopsy" bundle:nil];
firstViewController = [[tabBarController viewControllers] objectAtIndex:0];

DiseaseTableViewController *diseaseTableViewController = [[DiseaseTableViewController alloc] initWithNibName:@"DiseaseTableViewController" bundle:nil];
diseaseTableViewController = [[tabBarController viewControllers] objectAtIndex:1];

SecondViewController *secondViewController = [[SecondViewController alloc] 
                                              initWithNibName:@"TestYourSelf" bundle:nil];
secondViewController = [[tabBarController viewControllers] objectAtIndex:2];

ThirdViewController *thirdViewController = [[ThirdViewController alloc] initWithNibName:@"About" bundle:nil];
thirdViewController = [[tabBarController viewControllers] objectAtIndex:3];

// Override point for customization after application launch.
return YES;
}

This leads to a UITabBarController with a blank table in the TableView of the DiseaseTableViewController – because no data populated.
But if I do

diseaseTableViewController.diseases = diseases;

the app crashes with:

    Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-                [UINavigationController setDiseases:]: unrecognized selector sent to instance

So I tried to add the diseaseTableViewController to the navigationController:

diseaseTableViewController = [[navigationController viewControllers] objectAtIndex:1];

Which causes:

    Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[FirstViewController viewControllers]: unrecognized selector sent to instance 

I tried populating the DiseaseTableViewController in that class implementation rather than the AppDelegate but ended with a blank table in the UI again.

Any ideas?

Answer 1

I resolved this by leaving the original AppDelegate as is, and populating the data of DiseaseController.diseases in the viewDidLoad() kind of like what @Zhang mentioned