设置 UINavigationController 时“无法对类型进行比较查询:(空)" [英] 'Cannot do a comparison query for type: (null)' when setting up UINavigationController

问题描述

我的应用在应用委托中崩溃了.

My app is crashing in the app delegate.

它抛出的错误是:

由于未捕获的异常NSInvalidArgumentException"而终止应用，原因:无法对类型进行比较查询:(空)"

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Cannot do a comparison query for type: (null)'

我的代码如下.我已经把日志语句留在了，所以你可以看到我一直在检查的地方:

My code is below. I've left the logging statements in so you can see where I've been checking things:

self.viewController = [[ParseStarterProjectViewController alloc] initWithNibName:@"ParseStarterProjectViewController" bundle:nil];
NSLog(@"View controller is %@",self.viewController);
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:self.viewController];
NSLog(@"Nav controller is %@",navController);
NSLog(@"Self window is %@",self.window);
self.window.rootViewController = navController;

当它尝试运行最后一行时它会中断，将 rootViewController 设置为 navController.

It's breaking when it tries to run that last line, setting the rootViewController to the navController.

3 行 NSLog 的结果如下:

The results from the 3 NSLog lines are as follows:

View controller is <ParseStarterProjectViewController: 0x1fda0770>
Nav controller is <UINavigationController: 0x1fda1390>
Self window is <UIWindow: 0x1fd97c90; frame = (0 0; 320 480); opaque = NO; autoresize = RM+BM; layer = <UIWindowLayer: 0x1fd97d90>>

对我来说似乎没有任何东西是空的，这就是为什么我非常困惑.

It doesn't look like anything is null to me, which is why I'm extremely confused.

推荐答案

我刚刚遇到了这个问题，这是因为我在 PFQuery 中执行了一个 equalTo:[PFUser currentUser]但当时没有登录用户.

I just ran into this and it was due to the fact that I was doing an equalTo:[PFUser currentUser] in a PFQuery but there was no logged-in user at that point.

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