问题
My app is crashing in the app delegate.
The error it's throwing is:
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Cannot do a comparison query for type: (null)'
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;
It's breaking when it tries to run that last line, setting the rootViewController to the navController.
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>>
It doesn't look like anything is null to me, which is why I'm extremely confused.
回答1:
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.
回答2:
This really wound up being a question about "how do I get more information out of a crash log". rmaddy's comment pointed me in the right direciton.
Sean's answer here sorted me out.
来源：https://stackoverflow.com/questions/12965934/cannot-do-a-comparison-query-for-type-null-when-setting-up-uinavigationcont