NSClassFromString() always returns nil

Question

The following code prints `nil`, despite `ListCell` is a valid class. ``` var lCellClass : AnyClass! = NSClassFromString("ListCell"); println(lCellClass); ``` The docs are saying that method returns The class object named by aClassName, or `nil` if no class by that name is currently loaded. If aClassName is `nil`, returns `nil`. I also tried to get `NSClassFromString()` of current viewcontroller which is LOADED but still get `nil` What can be the problem ? Update: Even trying to do this `NSClassFromString("Array")` I still get `nil`

Accepted Answer

The `NSClassFromString` function does work for (pure and Objective-C-derived) swift classes, but only if you use the fully qualified name.

For example, in a module called `MyApp` with a pure swift class called `Person`:

```
let personClass: AnyClass? = NSClassFromString("MyApp.Person")
```

The module name is defined by the "Product Module Name" (`PRODUCT_MODULE_NAME`) build setting, typically the same name as your target (with some normalization applied to e.g. remove spaces).

This is atypical, but if the class you're loading is in the current module and you don't know the module name at compile-time e.g. because the code is compiled as part of multiple targets, you can look up the bundle name dynamically, which usually corresponds to the module name:

```
let moduleName = Bundle.main.infoDictionary!["CFBundleName"] as! String
let personClass: AnyClass? = NSClassFromString(moduleName + "." + "Person")
```

I don't recommend this however unless you really don't know at compile-time.

See Using Swift Class Names with Objective-C APIs in Using Swift With Cocoa and Objective-C for more information.

NSClassFromString() always returns nil

Solution

Problem