UITabBarItem未使用的表达式结果

Question

Im getting the warning "Expression result unused".

I dont know why this is showing. It is working correctly. Showing the right title and the images so why the warnings? what can i do to fix these warnings?

Thank you all for the help!

----------------------------------------------------- Edit 1

WHen i write it like this i get no warning.

   tabBarItem1 = [tabBarItem1 initWithTitle:@"Matcher Idag" image:[UIImage imageNamed:@"games-2.png"] selectedImage:[UIImage imageNamed:@"games-2.png"]];

BUT when i go to Product -> Analyze then it says: " Value stored to tabBarItem1 is never used

Answer 1

That code is very, very wrong.

Init methods return an object. You're supposed to use it, because sometimes the init method returns a different object than the one you started with.

You almost always use alloc and init together in a pair, eg:

tabBarItem1 = [[tabBarItem alloc] initWithTitle: @"title" 
  image: myImage
  selectedImage: anotherImage];

If you're not an experienced Objective-C developer and you're calling alloc and init separately, you are making a mistake. I can count on the fingers of 1 hand the number of times I've used init where it wasn't in the alloc/init pattern I showed above

The code you posted doesn't make a lot of sense. You shouldn't be sending init messages to objects that are already part of your tab bar. That's a no-no. Those objects have already been initialized, and you are only supposed to send one init message to an object in it's lifetime. What you are doing is going to cause problems. Big problems.

Instead you should use the title and image properties:

tableBarItem1.title = @"new title";
tableBarItem1.image  = myImage;
tableBarItem1.selectedImage  = mySelectedImage;