Dagger 2 Error: How Do I Resolve 'Cannot Be Provided'?

Dagger 2 Error: Resolve "Cannot Be Provided" Issue

)Problem Summary

Dagger 2 may display the following error when compiling a project:

error: com.example.MyDependency cannot be provided without an @Inject constructor or from an @Provides-annotated method.

This error indicates that Dagger lacks the necessary information to create or provide the specified dependency.

Understanding the Issue

Dagger requires a mechanism to provide or create the object it needs to inject. By default, it expects dependencies to have an @Inject-annotated constructor or a method in a module annotated with @Provides.

Resolution

There are two main approaches to resolving this issue:

1. Add an @Inject Annotated Constructor:

• Add an @Inject annotation to the constructor of the dependency class. For instance:

  class MyDependency {
    @Inject
    MyDependency() { /**/ }
  }

2. Create a @Provides-Annotated Method in a Module:

• Create a module class and add a method annotated with @Provides to it. This method will create or bind the desired dependency. For example:

  @Module
  class MyModule {
    @Provides
    MyDependency provideMyDependency() {
        return new MyDependency();
    }
  }

Additional Considerations

• Ensure that the dependency being provided is the same as the one being requested.
• Pay attention to interfaces and superclasses. Provide the implementation or extension when necessary.
• Consider using @Binds to link an implementation class to an interface or superclass.

The above is the detailed content of Dagger 2 Error: How Do I Resolve 'Cannot Be Provided'?. For more information, please follow other related articles on the PHP Chinese website!