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:

The following worked for me:

First, add gradle dependency the dagger for support library:

implementation "com.google.dagger:dagger-android-support:2.23.2"

Then in your fragment which is the child of androidx.fragment inject in the following way:

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"

Apart from this, if you are using for first time and migrating from support to AndroidX, you will also need to take care in gradle.properties as @Saeed Masoumi mentioned. You need to add following -

android.useAndroidX=true
android.enableJetifier=true

Jetifier will help you to migrate from support libraries to AndroidX packages at run time. Best answer you can find for that over here - https://stackoverflow.com/a/52002285/842607

回答4:

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5:

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.

来源：https://stackoverflow.com/questions/51827692/injecting-androidx-fragments-using-dagger-2

标签

android

dependency-injection

dagger-2

dagger