ViewController的NULL检查有什么问题？

Question

myCustomController *controller = [myMutableArray objectAtIndex:page];

NSLog(@"%@",controller); // <- THIS RETURNS NULL IN CONSOLE

if ((NSNull *)controller == [NSNull null]) {
 // Why is the above check not working if controller in console says it's null?
 // It's not jumping into this loop. Has something changed in iOS4.0 SDK?
}

对null进行viewController检查有什么问题，它似乎无法正常工作。

Answer 1

NSLog应该在控制台中返回(null)（可能是nil的说明），而不是NULL。您的支票应如下所示：

if (!controller) {
  // do some stuff here
}