Injecting Androidx Fragments using Dagger 2

问题:

I want to inject my Androidx fragments using dagger 2. In my activity I have:

  public class MainActivity extends AppCompatActivity implements HasSupportFragmentInjector
{
    @Inject Reposetory reposetory;
    @Inject DispatchingAndroidInjector<androidx.fragment.app.Fragment> dispatchingAndroidInjector;
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


    }

    @Override
    public AndroidInjector<androidx.fragment.app.Fragment> supportFragmentInjector()
    {
        return dispatchingAndroidInjector;
    }
}

the problem is when i want to build the project i get this error:

error: cannot find symbol class MapBuilder

and when i change androidx.fragment.app.Fragment to Fragment in DispatchingAndroidInjector i don't get this error any more.

回答1:

Androidx is not supported yet, but enabling jetifier maybe solve your problem.

Just add the below code to your gradle.properties

android.useAndroidX=true
android.enableJetifier=true

Also see these issues for detail:

• migration to androidx library

• AndroidInjection support for androidx Fragment

回答2:

as was suggested before, add the below code to your gradle.properties

android.useAndroidX=true
android.enableJetifier=true

And if you are trying to inject into a Fragment you have to replace AndroidInjection.inject(this) with AndroidSupportInjection.inject(this)

回答3:

Dagger supports were missing for AndroidX. It is added for version 2.21 and above

So you can use it as -

implementation 'com.google.dagger:dagger:2.21'
implementation 'com.google.dagger:dagger-android:2.21'
implementation 'com.google.dagger:dagger-android-support:2.21'
kapt "com.google.dagger:dagger-compiler:2.21"
kapt "com.google.dagger:dagger-android-processor:2.21"

回答4:

If jetifier does not change support packages to androidx packages. You can download jetifier tool from here and convert the android-dagger-support.aar file manually by using the following command.

./jetifier-standalone -i dagger-android-support-<version>.aar -o <output-name>

Then add the library to your project. This is the HasSupportFragment class after conversion

import androidx.fragment.app.Fragment;
import dagger.android.AndroidInjector;

public interface HasSupportFragmentInjector {
    AndroidInjector<Fragment> supportFragmentInjector();
}

Somehow, jetifier tool was not converting libraries in AndroidStudio. I had to do it manually.