我正在尝试创建一个简单的 Dagger 2 应用程序，同时使用支持 v4 fragment 。 在我修改我的应用程序后，我得到了这个奇怪的编译错误

Error:(35, 8) error: [dagger.android.AndroidInjector.inject(T)] java.util.Map<java.lang.Class<? extends android.support.v4.app.Fragment>,javax.inject.Provider<dagger.android.AndroidInjector.Factory<? extends android.support.v4.app.Fragment>>> cannot be provided without an @Provides-annotated method.
java.util.Map<java.lang.Class<? extends android.support.v4.app.Fragment>,javax.inject.Provider<dagger.android.AndroidInjector.Factory<? extends android.support.v4.app.Fragment>>> is injected at
dagger.android.DispatchingAndroidInjector.<init>(injectorFactories)
dagger.android.DispatchingAndroidInjector<android.support.v4.app.Fragment> is injected at
app.series.com.tvshowsapplication.ui.main.MainActivity.fragmentDispatchingAndroidInjector
app.series.com.tvshowsapplication.ui.main.MainActivity is injected at
dagger.android.AndroidInjector.inject(arg0)

快速搜索后，我找到了这个 link .它说我需要使用

问题是我不明白我应该把这部分放在哪里

@Multibinds
abstract Map<Class<? extends android.app.Fragment>, AndroidInjector.Factory<? extends android.app.Fragment>> bindNativeFragments();

我想我需要把它放在 BaseActivity 中，因为它是一个抽象函数，但我如何在主要 Activity 中实现它？

我的主要 Activity :

public class MainActivity extends BaseActivity<ActivityMainBinding, MainViewModel> implements MainNavigator, HasSupportFragmentInjector {

    @Inject
    ViewModelProvider.Factory mViewModelFactory;

    @Inject
    DispatchingAndroidInjector<Fragment> fragmentDispatchingAndroidInjector;

    private MainViewModel mMainViewModel;

    private DrawerLayout mDrawer;
    private Toolbar mToolbar;
    private NavigationView mNavigationView;
//    private SwipePlaceHolderView mCardsContainerView;

    ActivityMainBinding mActivityMainBinding;

    public static Intent getStartIntent(Context context) {
        Intent intent = new Intent(context, MainActivity.class);
        return intent;
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mActivityMainBinding = getViewDataBinding();
        mMainViewModel.setNavigator(this);
        setUp();
    }

    @Override
    protected void onResume() {
        super.onResume();
        if (mDrawer != null)
            mDrawer.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED);
    }

    public void onFragmentDetached(String tag) {
        FragmentManager fragmentManager = getSupportFragmentManager();
        Fragment fragment = fragmentManager.findFragmentByTag(tag);
        if (fragment != null) {
            fragmentManager
                    .beginTransaction()
                    .disallowAddToBackStack()
                    .setCustomAnimations(R.anim.slide_left, R.anim.slide_right)
                    .remove(fragment)
                    .commitNow();
            unlockDrawer();
        }
    }

    private void setUp() {

        mDrawer = mActivityMainBinding.drawerView;
        mToolbar = mActivityMainBinding.toolbar;
        mNavigationView = mActivityMainBinding.navigationView;
//        mCardsContainerViewerView = mActivityMainBinding.cardsContainer;

        setSupportActionBar(mToolbar);
        ActionBarDrawerToggle mDrawerToggle = new ActionBarDrawerToggle(
                this,
                mDrawer,
                mToolbar,
                R.string.open_drawer,
                R.string.close_drawer) {
            @Override
            public void onDrawerOpened(View drawerView) {
                super.onDrawerOpened(drawerView);
                hideKeyboard();
            }

            @Override
            public void onDrawerClosed(View drawerView) {
                super.onDrawerClosed(drawerView);
            }
        };
        mDrawer.addDrawerListener(mDrawerToggle);
        mDrawerToggle.syncState();
        setupNavMenu();
        String version = getString(R.string.version) + " " + BuildConfig.VERSION_NAME;
        mMainViewModel.updateAppVersion(version);
        mMainViewModel.onNavMenuCreated();
//        setupCardContainerView();
        subscribeToLiveData();
    }

    private void subscribeToLiveData() {

    }



    private void setupNavMenu() {
        NavHeaderMainBinding navHeaderMainBinding = DataBindingUtil.inflate(getLayoutInflater(),
                R.layout.nav_header_main, mActivityMainBinding.navigationView, false);
        mActivityMainBinding.navigationView.addHeaderView(navHeaderMainBinding.getRoot());
        navHeaderMainBinding.setViewModel(mMainViewModel);

        mNavigationView.setNavigationItemSelectedListener(
                new NavigationView.OnNavigationItemSelectedListener() {
                    @Override
                    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                        mDrawer.closeDrawer(GravityCompat.START);
                        switch (item.getItemId()) {
//                            case R.id.navItemAbout:
//                                showAboutFragment();
//                                return true;
//                            case R.id.navItemRateUs:
//                                RateUsDialog.newInstance().show(getSupportFragmentManager());
//                                return true;
//                            case R.id.navItemFeed:
//                                startActivity(FeedActivity.getStartIntent(MainActivity.this));
//                                return true;
//                            case R.id.navItemLogout:
//                                mMainViewModel.logout();
//                                return true;
//                            default:
//                                return false;
                        }
                        return false;
                    }
                });
    }

//    private void showAboutFragment() {
//        lockDrawer();
//        getSupportFragmentManager()
//                .beginTransaction()
//                .disallowAddToBackStack()
//                .setCustomAnimations(R.anim.slide_left, R.anim.slide_right)
//                .add(R.id.clRootView, AboutFragment.newInstance(), AboutFragment.TAG)
//                .commit();
//    }

    private void lockDrawer() {
        if (mDrawer != null)
            mDrawer.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED);
    }

    private void unlockDrawer() {
        if (mDrawer != null)
            mDrawer.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED);
    }


    @Override
    public void openLoginActivity() {
        startActivity(LoginActivity.getStartIntent(this));
        finish();
    }

    @Override
    public void handleError(Throwable throwable) {
        // handle error
    }

    @Override
    public MainViewModel getViewModel() {
        mMainViewModel = ViewModelProviders.of(this, mViewModelFactory).get(MainViewModel.class);
        return mMainViewModel;
    }

    @Override
    public int getBindingVariable() {
        return BR.viewModel;
    }

    @Override
    public int getLayoutId() {
        return R.layout.activity_main;
    }

    @Override
    public AndroidInjector<Fragment> supportFragmentInjector() {
        return fragmentDispatchingAndroidInjector;
    }
}

更新

我实际上在组件类中添加了模块，这里是我的 AppComponent

@Singleton
@Component(modules = {AndroidInjectionModule.class, AppModule.class, ActivityBuilder.class})
public interface AppComponent {

    @Component.Builder
    interface Builder {

        @BindsInstance
        Builder application(Application application);

        AppComponent build();

    }

    void inject(TVShowsApp app);

}

应用模块

@Module
public class AppModule {

    @Provides
    @Singleton
    Context provideContext(Application application) {
        return application;
    }


    @Provides
    @Singleton
    CalligraphyConfig provideCalligraphyDefaultConfig() {
        return new CalligraphyConfig.Builder()
                .setDefaultFontPath("fonts/source-sans-pro/SourceSansPro-Regular.ttf")
                .setFontAttrId(R.attr.fontPath)
                .build();
    }
}

和 ActivityBuilder

@Module
public abstract class ActivityBuilder {

    @ContributesAndroidInjector(modules = MainActivityModule.class)
    abstract MainActivity bindMainActivity();

}

最佳答案

你需要把它放在一个模块中，然后在你的组件中注册，但你不必手动声明它，因为 Dagger 已经有了 AndroidInjectionModule(或 AndroidSupportInjectionModule 与 AppCompat)，你可以使用。

您可以在 official documentation 中找到有关 Android 设置的更多信息或在有关 when you need to install the module 的类似问题中查看一些附加信息这是最近有人问的。

您没有显示您的 AppComponent，但您很可能只是忘记添加该模块，因此您可以通过将其添加到您的组件来修复错误。

// add it somehow like this
@Component(modules = { AndroidSupportInjectionModule.class, AppModule.class })
public interface AppComponent {
  void inject(App app);
}

关于android - 使用支持 fragment 时的 fragmentDispatchingAndroidInjector，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/48482202/