First baby steps into the world of dependency injection using Dagger.

app/src/main/java/fr/free/nrw/commons/di/ActivityBuilderModule.java

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+package fr.free.nrw.commons.di;
+
+import dagger.Module;
+import dagger.android.ContributesAndroidInjector;
+import fr.free.nrw.commons.AboutActivity;
+import fr.free.nrw.commons.WelcomeActivity;
+import fr.free.nrw.commons.auth.LoginActivity;
+import fr.free.nrw.commons.auth.SignupActivity;
+import fr.free.nrw.commons.contributions.ContributionsActivity;
+import fr.free.nrw.commons.nearby.NearbyActivity;
+import fr.free.nrw.commons.settings.SettingsActivity;
+import fr.free.nrw.commons.upload.MultipleShareActivity;
+import fr.free.nrw.commons.upload.ShareActivity;
+
+@Module
+public abstract class ActivityBuilderModule {
+
+    @ContributesAndroidInjector
+    abstract ContributionsActivity bindContributionsActivity();
+
+    @ContributesAndroidInjector
+    abstract MultipleShareActivity bindMultipleShareActivity();
+
+    @ContributesAndroidInjector
+    abstract ShareActivity bindShareActivity();
+
+    @ContributesAndroidInjector
+    abstract LoginActivity bindLoginActivity();
+
+    @ContributesAndroidInjector
+    abstract SignupActivity bindSignupActivity();
+
+    @ContributesAndroidInjector
+    abstract NearbyActivity bindNearbyActivity();
+
+    @ContributesAndroidInjector
+    abstract AboutActivity bindAboutActivity();
+
+    @ContributesAndroidInjector
+    abstract SettingsActivity bindSettingsActivity();
+
+    @ContributesAndroidInjector
+    abstract WelcomeActivity bindWelcomeActivity();
+
+}

app/src/main/java/fr/free/nrw/commons/di/CommonsApplicationComponent.java

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+package fr.free.nrw.commons.di;
+
+import javax.inject.Singleton;
+
+import dagger.Component;
+import dagger.android.AndroidInjectionModule;
+import dagger.android.AndroidInjector;
+import fr.free.nrw.commons.CommonsApplication;
+import fr.free.nrw.commons.auth.WikiAccountAuthenticatorService;
+import fr.free.nrw.commons.contributions.ContributionsSyncAdapter;
+import fr.free.nrw.commons.modifications.ModificationsSyncAdapter;
+
+@Singleton
+@Component(modules = {
+        CommonsApplicationModule.class,
+        AndroidInjectionModule.class,
+        ActivityBuilderModule.class,
+        ContentProviderBuilderModule.class
+})
+public interface CommonsApplicationComponent extends AndroidInjector<CommonsApplication> {
+    void inject(CommonsApplication application);
+
+    void inject(WikiAccountAuthenticatorService service);
+
+    void inject(ContributionsSyncAdapter syncAdapter);
+
+    void inject(ModificationsSyncAdapter syncAdapter);
+
+    @Component.Builder
+    interface Builder {
+        Builder appModule(CommonsApplicationModule applicationModule);
+
+        CommonsApplicationComponent build();
+    }
+}

app/src/main/java/fr/free/nrw/commons/di/CommonsApplicationModule.java

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+package fr.free.nrw.commons.di;
+
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+import fr.free.nrw.commons.CommonsApplication;
+import fr.free.nrw.commons.mwapi.ApacheHttpClientMediaWikiApi;
+import fr.free.nrw.commons.mwapi.MediaWikiApi;
+
+@Module
+public class CommonsApplicationModule {
+    private CommonsApplication application;
+
+    public CommonsApplicationModule(CommonsApplication application) {
+        this.application = application;
+    }
+
+    @Provides
+    public CommonsApplication providesCommonsApplication() {
+        return application;
+    }
+
+    @Provides
+    @Singleton
+    public MediaWikiApi provideMediaWikiApi() {
+        return new ApacheHttpClientMediaWikiApi(CommonsApplication.API_URL);
+    }
+}

app/src/main/java/fr/free/nrw/commons/di/ContentProviderBuilderModule.java

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+package fr.free.nrw.commons.di;
+
+import dagger.Module;
+import dagger.android.ContributesAndroidInjector;
+import fr.free.nrw.commons.auth.LoginActivity;
+import fr.free.nrw.commons.auth.SignupActivity;
+import fr.free.nrw.commons.category.CategoryContentProvider;
+import fr.free.nrw.commons.contributions.ContributionsActivity;
+import fr.free.nrw.commons.contributions.ContributionsContentProvider;
+import fr.free.nrw.commons.modifications.ModificationsContentProvider;
+
+@Module
+public abstract class ContentProviderBuilderModule {
+
+    @ContributesAndroidInjector
+    abstract CategoryContentProvider bindCategoryContentProvider();
+
+    @ContributesAndroidInjector
+    abstract ContributionsContentProvider bindContributionsContentProvider();
+
+    @ContributesAndroidInjector
+    abstract ModificationsContentProvider bindModificationsContentProvider();
+
+}