Dagger 2 Dependency Errors: How Can I Fix the '... cannot be provided [...]' Issue?

How to Resolve Dagger 2 Dependency Errors

Issue: Dagger 2 Error: "... cannot be provided [...]"

This error occurs when Dagger 2 is unable to provide a dependency without an @Inject-annotated constructor or an @Provides-annotated method.

Explanation:

Dagger 2 relies on annotation-based dependency injection to create and provide objects. Without an @Inject constructor or an @Provides method, Dagger does not have a way to create the dependency.

Solutions:

Use Constructor Injection:

• Add an @Inject-annotated constructor to the dependent class. This allows Dagger to use constructor injection to create the object.

Use a @Provides Method:

• Create a module and add an @Provides-annotated method to provide the dependency. Add this module to your component.

Example with Constructor Injection:

class MyDependency {

    // Add `@Inject` annotation to the constructor
    @Inject
    public MyDependency() {}
}

Example with @Provides Method:

@Module
public class MyModule {

    @Provides
    public MyDependency provideMyDependency() {
        return new MyDependency();
    }
}

@Component(modules = MyModule.class)
public interface MyComponent {
    MyDependency myDependency();
}

Pay Attention to Details:

• Make sure you provide and request the same type of dependency.
• Check for typos and mismatched annotations in your code.
• Double-check that you have added the necessary module to your component.

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