Dagger2:没有注射器工厂限制碎片

Question

我正在尝试将我正在构建的项目转换为使用dagger-android API用于DI框架,但是当尝试使用@ContributesAnroidInjector注入片段时,我遇到了IllegalArgumentException的死胡同.

相关模块和组件包括在下面:

ApplicationComponent.java

@Singleton
@Component(modules = {AndroidSupportInjectionModule.class,
    ApplicationModule.class,
    ActivityBindingModule.class,
    DataManagerModule.class})
public interface ApplicationComponent extends AndroidInjector<MyApplication> {

DataManagerContract getDataManager();

void inject(MyApplication application);

@Component.Builder
interface Builder {

    @BindsInstance
    ApplicationComponent.Builder application(Application application);

    ApplicationComponent build();
    }
}

我的ActivityBindingModule.java:

@Module
public abstract class ActivityBindingModule {

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

    @ActivityScope
    @ContributesAndroidInjector(modules = SplashActivityModule.class)
    abstract SplashActivity bindSplashActivity();

    @ActivityScope
    @ContributesAndroidInjector(modules = LoginActivityModule.class)
    abstract LoginActivity bindLoginActivity();
}

MainActivityModule.java

@Module
public abstract class MainActivityModule {

    @ActivityScope
    @Binds
    abstract MainActivityContract.Presenter provideMainActivityPresenter(MainActivityPresenter presenter);

    @FragmentScope
    @ContributesAndroidInjector
    abstract HomeFragment provideHomeFragment();

    @FragmentScope
    @Binds
    abstract HomeFragmentContract.Presenter provideHomeFragmentPresenter(HomeFragmentPresenter presenter);

    // Inject other fragments and presenters
}

SplashActivity和LoginActivity仅取决于他们各自的演示者,并且匕首在这些方面工作得很好.但是我的MainActivity可以包含许多片段,并在尝试使用以下方法注入其中一个片段时导致崩溃:

HomeFragment.java

public class HomeFragment extends Fragment {
    ....
    @Override
    public void onAttach(Context context) {
        AndroidSupportInjection.inject(this);
        super.onAttach(context);
    }
    ....
}

这是我崩溃的logcat:

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.myapp/com.myapp.main.MainActivity}: java.lang.IllegalArgumentException: No injector factory bound for Class<com.myapp.ui.main.Home.HomeFragment>
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2665)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
Caused by: java.lang.IllegalArgumentException: No injector factory bound for Class<com.myapp.ui.main.Home.HomeFragment>
        at dagger.android.DispatchingAndroidInjector.inject(DispatchingAndroidInjector.java:104)
        at dagger.android.support.AndroidSupportInjection.inject(AndroidSupportInjection.java:74)
        at com.myapp.ui.main.Home.HomeFragment.onAttach(HomeFragment.java:65)
        at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1363)
        at android.support.v4.app.FragmentTransition.addToFirstInLastOut(FragmentTransition.java:1109)
        at android.support.v4.app.FragmentTransition.calculateFragments(FragmentTransition.java:996)
        at android.support.v4.app.FragmentTransition.startTransitions(FragmentTransition.java:99)
        at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2364)
        at android.support.v4.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2322)
        at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2229)
        at android.support.v4.app.FragmentManagerImpl.dispatchStateChange(FragmentManager.java:3221)
        at android.support.v4.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManager.java:3171)
        at android.support.v4.app.FragmentController.dispatchActivityCreated(FragmentController.java:192)
        at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:560)
        at android.support.v7.app.AppCompatActivity.onStart(AppCompatActivity.java:177)
        at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1248)
        at android.app.Activity.performStart(Activity.java:6696)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2628)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726) 
        at android.app.ActivityThread.-wrap12(ActivityThread.java) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477) 
        at android.os.Handler.dispatchMessage(Handler.java:102) 
        at android.os.Looper.loop(Looper.java:154) 
        at android.app.ActivityThread.main(ActivityThread.java:6119) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

我不确定代码中的问题在哪里.如果我将HomeFragment的绑定移动到ActivityBindingModule,应用程序运行正常,但如果我将这些绑定带回MainActivityModule,则会发生崩溃.我在这做错了什么？

编辑:

public class MyApp extends DaggerApplication {

    @Override
    protected AndroidInjector<? extends DaggerApplication> applicationInjector() {
        return DaggerApplicationComponent.builder().application(this).build();
    }
}

和我的主要活动:

public class MainActivity extends AppCompatActivity
    implements MainActivityContract.View,
    NavigationView.OnNavigationItemSelectedListener {

@Inject
MainActivityContract.Presenter mPresenter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    AndroidInjection.inject(this);
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // Open home fragment on first start
    if (savedInstanceState == null) {
        // Create new instance of HomeFragment
        HomeFragment homeFragment = HomeFragment.newInstance();

        FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
        fragmentTransaction.replace(R.id.content_main, homeFragment)
                .commit();
    }

// Other logic
}

Answer 1

当您AndroidSupportInjection.inject(this)从中注入使用时HomeFragment,Dagger将遍历父片段层次结构以找到实现的人HasSupportFragmentInjector.为了使它工作,使你的MainActivity扩展DaggerAppCompatActivity实现HasSupportFragmentInjector.

来自以下文件AndroidSupportInjection.inject(Fragment fragment):

如果可以找到关联的{@link dagger.android.AndroidInjector}实现,则注入{@code fragment},否则抛出{@link IllegalArgumentException}.

使用以下算法查找用于注入{@code fragment}的相应{@code AndroidInjector}:

1. 遍历父片段层次结构以查找实现{@link HasSupportFragmentInjector}的片段,如果没有,则执行
2. 如果它实现{@link HasSupportFragmentInjector},则使用{@code fragment}的{@link Fragment#getActivity()activity},如果没有
3. 如果它实现了{@link HasSupportFragmentInjector},则使用{@link android.app.Application}.

如果它们都没有实现{@link HasSupportFragmentInjector},则抛出{@link IllegalArgumentException}.

@throws IllegalArgumentException如果没有父片段,活动或应用程序实现{@link HasSupportFragmentInjector}.

有了这个,Dagger就会使用

@FragmentScope
@ContributesAndroidInjector
abstract HomeFragment provideHomeFragment();

从你MainActivityModule注入你的内心HomeFragment.