使用改型android时，Dagger2在主要活动中出现问题

使用dagger2注入改装服务对象时，我面临一个问题。以下是我的场景的详细信息：

改装Web服务类别：

public interface WebService {                                                               
    Observable<Name> searchName(@Query("id") String id);
}

@Module
public class SetupModule {

    @Provides
   MainActivity provideWebService(WebService webService) {
        return new MainActivity(webService);
    }
}

@SetupScope
@Subcomponent(modules = SubModule.class)
public interface SubComponent {
    MainActivity inject(MainActivity mainActivity);
}

@Singleton
@Component(modules = {
        AppModule.class,
        NetworkModule.class})
public interface AppComponent
{
    SubComponent plus(SubModule subModule);
}

 public SubComponent createSubComponent()
    {
        subComponent = appComponent.plus(new subModule());
        return subComponent;
    }

 public MainActivity(WebService webService) {
        this.webService = webService;
    }

@Override
    protected void onCreate(Bundle savedInstanceState) {
((BaseApplication) getApplication()).createSubComponent().inject(this);
}

下面是子组件类：

public interface WebService {                                                               
    Observable<Name> searchName(@Query("id") String id);
}

@Module
public class SetupModule {

    @Provides
   MainActivity provideWebService(WebService webService) {
        return new MainActivity(webService);
    }
}

@SetupScope
@Subcomponent(modules = SubModule.class)
public interface SubComponent {
    MainActivity inject(MainActivity mainActivity);
}

@Singleton
@Component(modules = {
        AppModule.class,
        NetworkModule.class})
public interface AppComponent
{
    SubComponent plus(SubModule subModule);
}

 public SubComponent createSubComponent()
    {
        subComponent = appComponent.plus(new subModule());
        return subComponent;
    }

 public MainActivity(WebService webService) {
        this.webService = webService;
    }

@Override
    protected void onCreate(Bundle savedInstanceState) {
((BaseApplication) getApplication()).createSubComponent().inject(this);
}

这里是AppComponent类：

public interface WebService {                                                               
    Observable<Name> searchName(@Query("id") String id);
}

@Module
public class SetupModule {

    @Provides
   MainActivity provideWebService(WebService webService) {
        return new MainActivity(webService);
    }
}

@SetupScope
@Subcomponent(modules = SubModule.class)
public interface SubComponent {
    MainActivity inject(MainActivity mainActivity);
}

@Singleton
@Component(modules = {
        AppModule.class,
        NetworkModule.class})
public interface AppComponent
{
    SubComponent plus(SubModule subModule);
}

 public SubComponent createSubComponent()
    {
        subComponent = appComponent.plus(new subModule());
        return subComponent;
    }

 public MainActivity(WebService webService) {
        this.webService = webService;
    }

@Override
    protected void onCreate(Bundle savedInstanceState) {
((BaseApplication) getApplication()).createSubComponent().inject(this);
}

下面是BaseApplication类中的组件创建：

public interface WebService {                                                               
    Observable<Name> searchName(@Query("id") String id);
}

@Module
public class SetupModule {

    @Provides
   MainActivity provideWebService(WebService webService) {
        return new MainActivity(webService);
    }
}

@SetupScope
@Subcomponent(modules = SubModule.class)
public interface SubComponent {
    MainActivity inject(MainActivity mainActivity);
}

@Singleton
@Component(modules = {
        AppModule.class,
        NetworkModule.class})
public interface AppComponent
{
    SubComponent plus(SubModule subModule);
}

 public SubComponent createSubComponent()
    {
        subComponent = appComponent.plus(new subModule());
        return subComponent;
    }

 public MainActivity(WebService webService) {
        this.webService = webService;
    }

@Override
    protected void onCreate(Bundle savedInstanceState) {
((BaseApplication) getApplication()).createSubComponent().inject(this);
}

这是主活动类：

public interface WebService {                                                               
    Observable<Name> searchName(@Query("id") String id);
}

@Module
public class SetupModule {

    @Provides
   MainActivity provideWebService(WebService webService) {
        return new MainActivity(webService);
    }
}

@SetupScope
@Subcomponent(modules = SubModule.class)
public interface SubComponent {
    MainActivity inject(MainActivity mainActivity);
}

@Singleton
@Component(modules = {
        AppModule.class,
        NetworkModule.class})
public interface AppComponent
{
    SubComponent plus(SubModule subModule);
}

 public SubComponent createSubComponent()
    {
        subComponent = appComponent.plus(new subModule());
        return subComponent;
    }

 public MainActivity(WebService webService) {
        this.webService = webService;
    }

@Override
    protected void onCreate(Bundle savedInstanceState) {
((BaseApplication) getApplication()).createSubComponent().inject(this);
}

在尝试从MainActivity访问webservice接口中的searchName方法时，我收到了

webservice nullpointerexception

---

请帮我找出为什么webservice对象会变为null？

我认为，首先应该从活动构造函数中删除webservice，并启动类似这样的服务：

@Inject
WebService webService;

---

对于android中的活动和片段，构造函数注入是不可能的。你必须在野外注射时给出提示，在这种情况下我该怎么做？参考匕首2的任何指南，这是基本的匕首，看起来很有效。但是为什么我需要从活动构造函数中删除webservice呢。因为我通过子模块活动构造函数提供依赖关系。