How to Prevent Clients from Accessing Internal Private Classes in an Android Library?

How can I restrict clients from accessing internal private classes in my Android library?

// Place internal classes in the correct package structure to hide them from the public API.

In Android development, safeguarding the internal structure of your library is crucial for maintaining code integrity and preventing misuse by clients. This can be achieved through various practices that ensure private classes remain hidden and inaccessible from external users.

// Example of package-private class in Java
class InternalClass {
    void internalMethod() {
        // Implementation
    }
}

// Example of Kotlin's internal modifier
internal class InternalKotlinClass {
    fun internalFunction() {
        // Implementation
    }
}

Causes

• Using public visibility modifiers for classes that should be private.
• Not adhering to package-level visibility, allowing internal classes to be exposed.

Solutions

• Use package-private classes (default visibility) for internal functionality that should not be exposed publicly.
• Employ the 'internal' modifier for Kotlin libraries to restrict access to contained classes only within the module.
• Organize your codebase to clearly separate public API from internal workings, leveraging sub-packages effectively.

Mistake: Making all classes public without considering access modifiers.

Solution: Review your class visibility and restrict to package-private or internal as necessary.

Mistake: Exposing too much functionality in the library public API.

Solution: Limit the public API to only essential methods and classes.