我如何知道是否已加载NIB文件？

Question

I made a series of UIView subclasses. Each is inherited from another.

In the grand grand parents of all the subclass is this code:

NSString * className = NSStringFromClass([self class]);
[[NSBundle mainBundle] loadNibNamed:className owner:self options:nil];

The problem with this code is that not all subclasses have their own NIB. Some resort to using the NIB of their parent class.

I want to check whether the UIView has been loaded from NIB or not before executing the code.

How would I do so?

Answer 1

That code will not works as you expected, sorry: you use NSStringFromClass([self class]) to get the nib name, so if it doesn't exist a nib with the class name it will not loaded and the object will be nil. There's no sort of inheritance in NIB. You could try using explicit nib name when the classname fails. Something like:

id myView = [[NSBundle mainBundle] loadNibNamed:className owner:self options:nil];
if (!myView)
    myView = [[NSBundle mainBundle] loadNibNamed:@"defaultNIBname" owner:self options:nil];

or you could get all the object hierarchy classes and try them all till you find one NIB..