Question

This one is new to me. Not even sure what RootViewController.o is? though this project does have a .m & .h. Building for Simulator 3.0. Cleaned before build (Shift-⌘-K).

Recently added some classes from another project that also had a RootViewController…but I didn’t transfer old one over. Haven’t built since. This could be part of the problem?!?

Building target “MyApp” of project “MyApp” with configuration “Debug” — (1 error)

    cd "/Volumes/MacHD/Development/iPhone/MyApp"
    setenv MACOSX_DEPLOYMENT_TARGET 10.5
    setenv PATH "/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
    /Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/gcc-4.2 -arch i386 -isysroot /Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator3.0.sdk -L/Volumes/MacHD/Development/iPhone/MyApp/build/Debug-iphonesimulator -F/Volumes/MacHD/Development/iPhone/MyApp/build/Debug-iphonesimulator -filelist /Volumes/MacHD/Development/iPhone/MyApp/build/MyApp.build/Debug-iphonesimulator/MyApp.build/Objects-normal/i386/MyApp.LinkFileList -mmacosx-version-min=10.5 -framework Foundation -framework UIKit -framework CoreGraphics -framework AddressBook -framework AddressBookUI -o /Volumes/MacHD/Development/iPhone/MyApp/build/Debug-iphonesimulator/MyApp.app/MyApp
Undefined symbols:
  ".objc_class_name_MyViewController", referenced from:
      literal-pointer@__OBJC@__cls_refs@MyViewController in RootViewController.o
ld: symbol(s) not found
collect2: ld returned 1 exit status

Build failed (1 error)

---

Edit: Cleaned ALL targets… still won’t build. Here’s my #includes:

RootViewController.h:

#import <UIKit/UIKit.h>
#import "MyViewController.h" //tried with this and as @class MyViewController

@class AddViewController, EditingViewController;

@interface RootViewController : UITableViewController <UITableViewDelegate, UITableViewDataSource> {
    MyViewController *myVC;
    UINavigationController *navController;
    AddViewController *addViewController;
    NSArray *keys;
    NSNumberFormatter *currencyFormatter;
}

RootViewController.m:

#import "RootViewController.h"
#import "MyAppDelegate.h"
#import "MyViewController.h"
#import "AddViewController.h" 
#import "EditingViewController.h"
#import "MyObject.h"
#import "ViewCell.h"
#import "AppColors.h"
#import "CustomCellBackgroundView.h"

// Manage the editing view controller from this class so it can be easily accessed from both the detail and add controllers.
static EditingViewController *__editingViewController = nil;

@implementation RootViewController

Answer 1

RootViewController.m has a reference in it somewhere to MyViewController, but you haven’t linked in a file with an @implementation MyViewController in it. RootViewController.o is the object file created by compiling RootViewController.m.