在类型“y *”的对象上找不到属性“x”，只有ARC [英] Property 'x' not found on object of type 'y *' error only with ARC

问题描述

这个错误很奇怪。我有一大堆属性在应用程序委托，我没有问题，访问。我的代码工作正常没有ARC，但当我打开ARC我收到这个非常奇怪的错误。
在'AppDelegate *'类型的对象上没有找到属性'navigationController'

This error very strange. I have a bunch of properties in app delegate which I have no problem to access. My code worked fine without ARC, but when I turned on ARC I receive this very strange error. Property 'navigationController' not found on object of type 'AppDelegate *'

除此之外，一系列其他属性都很好。

A bunch of other properties work just fine except this.

我已经清理所有内容并重新启动Xcode。

I already clean everything and restarted Xcode.

这是代码：

AppDelegate.h：

AppDelegate.h:

@interface AppDelegate : UIResponder <UINavigationControllerDelegate> {
    UINavigationController *navigationController;
    NSString *appName;
}
@property (strong, nonatomic) NSString *appName;
@property (strong, nonatomic) UINavigationController *navigationController;

AppDelegate.m

AppDelegate.m

    #import "AppDelegate.h"
    @synthesize navigationController, appName;

    - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
        appName = [NSString stringWithString:[[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleName"]];
        navigationController = [[UINavigationController alloc] initWithRootViewController:self.startViewController];
}

MyClass.h

MyClass.h

@class AppDelegate;
@interface MyClass: UIResponder {
    AppDelegate *appDelegate;

}

MyClass.m

MyClass.m

#import "AppDelegate.h"
#import "MyClass.h"

@implementation MyClass 
- (id)init
{
    self = [super init];
    if (self) {
        // Initialization code here. 
        appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate]; 
        [self initFacebook];
    }
    return self;
}

- (void) doStuff {
    NSLog(@"App Name:%@",appDelegate.appName); //this works fine

    //This one doesn't
    UINavigationController *myNavigationController = appDelegate.navigationController;
}

更新：
我做了一个解决方法。基本上，我在MyClass中创建了一个名为navigationViewController的属性，我在AppDelegate中实例化MyClass之后传递对象，而不是直接从MyCLass中的AppDelegate获取（如上所示）。我还是困惑，它一定是编译器中的一个错误。我仍然非常感兴趣如何使原始代码工作。

Update: I did a workaround. Basically I created a property in MyClass called navigationViewController and I pass the object after MyClass is instantiated in AppDelegate instead of getting directly from AppDelegate in MyCLass (as shown above). I'm still puzzled, it must be a bug in the compiler. I'm still very interested in how to make the original code work.

推荐答案

在MyClass.m，导入MyClass而不是MyClass.h。

有时清理项目是不够的：您可能需要打开管理器窗口，在项目选项卡下选择您的项目，并单击按钮以删除衍生数据。

Sometimes cleaning a project is not sufficient: you may need to open the Organizer window, select your project under the Projects tab, and click the button to delete Derived Data.

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