Dagger AndroidInjector cannot be provided without

问题:

I've done my Android projects MainActivity by means of the MVP pattern. So in my MainPresenter I want to inject a dynamic String, which then shall populate a TextView for instance:

class MyMainPresenter @Inject constructor(@StringForTextView dynamicString : String ) 

whereas the StringForTextView annotation qualifier is defined as:

import javax.inject.Qualifier
@Qualifier
@MustBeDocumented
@Retention(AnnotationRetention.RUNTIME)
annotation class StringForTextView

then I also have my Interface:

interface DynamicString {
    @NonNull fun getDynamicString() : String
}

which is implemented as:

data class SimpleDynamicString(val dynString: String) : DynamicString {
    override fun getDynamicString(): String { return dynString }
}

then in my module:

@Provides
@StringForTextView
static DynamicString provideDynamicString(Application application)
{
    return new SimpleDynamicString(application.getString(R.string.example_string));
}

The problem is, that I get an error

Error:(51, 2) error: [dagger.android.AndroidInjector.inject(T)] @com.ralf.example.injection.qualifiers.StringForTextView java.lang.String cannot be provided without an @Provides-annotated method.

What am I missing?

回答1:

You're providing a DynamicString while expecting a regular String in the constructor. You should use DynamicString there as well:

class MyMainPresenter @Inject constructor(
    @StringForTextView dynamicString: DynamicString
)

Also, you might want to hols on to that injected value by making it a property with val.