我想制作一个包含一个主要活动和多个片段的简单项目。 在这里,我在一次活动中有两个片段,我想注入演示者来登录片段,但是它不起作用。我的错误在哪里?
MainApplication.java
public class MainApplication extends DaggerApplication{
private static ApplicationComponent component;
@Override
public void onCreate() {
super.onCreate();
Utils.init(this);
}
public static ApplicationComponent getComponent() {
return component;
}
protected AndroidInjector<? extends DaggerApplication> applicationInjector()
{
component =
DaggerApplicationComponent.builder().application(this).build();
component.inject(this);
return component;
}
}
MainActivity.java
public class MainActivity extends DaggerAppCompatActivity {
private Fragment[] mFragments = new Fragment[2];
private int curIndex;
@Inject
HomeFragment homeFragment;
@Inject
LoginFragment loginFragment;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState != null) {
curIndex = savedInstanceState.getInt("curIndex");
}
mFragments[AppConstant.HOME_FRAGMENT] = homeFragment;
mFragments[AppConstant.LOGIN_FRAGMENT] = loginFragment;
FragmentUtils.add(getSupportFragmentManager(), mFragments,
R.id.container, curIndex);
showCurrentFragment(AppConstant.LOGIN_FRAGMENT);
}
private void showCurrentFragment(int index) {
FragmentUtils.showHide(curIndex = index, mFragments);
}
@Override
public void onSaveInstanceState(Bundle outState, PersistableBundle
outPersistentState) {
super.onSaveInstanceState(outState, outPersistentState);
outState.putInt("curIndex", curIndex);
}
}
ApplicationComponent.java
@Singleton
@Component(modules = {
ContextModule.class,
ApiServiceModule.class,
AndroidSupportInjectionModule.class,
ActivityBuilder.class
})
public interface ApplicationComponent extends
AndroidInjector<DaggerApplication> {
void inject(MainApplication component);
@Component.Builder
interface Builder {
ApplicationComponent build();
@BindsInstance
Builder application(MainApplication application);
}
}
LoginFragment.java
public class LoginFragment extends DaggerFragment{
View mRootView;
@Inject
HomeFragment homeFragment;
@Inject
LoginContract.Presenter mPresenter;
@Inject
public LoginFragment() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
mRootView =inflater.inflate(R.layout.fragment_login, container, false);
ButterKnife.bind(this,mRootView);
// Inflate the layout for this fragment
return mRootView;
}
@OnClick(R.id.button)
public void goToHome(){
FragmentUtils.replace(this,homeFragment,false);
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
}
@Override
public void onDetach() {
super.onDetach();
}
}
ActivityBuilder.java
@Module
public abstract class ActivityBuilder {
@ContributesAndroidInjector(modules = {MainActivityModule.class ,
FragmentContainerModule.class, AndroidSupportInjectionModule.class} )
abstract MainActivity bindMainActivity();
}
FragmentContainerModule.java
@Module
public abstract class FragmentContainerModule {
@ContributesAndroidInjector(modules =
{HomeFragmentModule.class,
AndroidSupportInjectionModule.class})
abstract HomeFragment contributeHomeFragmentInjector();
@FragmentScope
@ContributesAndroidInjector(modules =
{LoginFragmentModule.class,
AndroidSupportInjectionModule.class})
abstract LoginFragment contributeLoginFragmentInjector();
}
** LoginFragmentModule.java
@Module
public abstract class LoginFragmentModule {
@FragmentScope
@Binds
public abstract LoginContract.Presenter presenter(LoginPresenter
loginPresenter);
}
这是错误:
error: [Dagger/MissingBinding] [dagger.android.AndroidInjector.inject(T)]
ir.heart.heartproject.utils.MvpUtils.LoginContract.Presenter cannot be
provided without an @Provides-annotated method.
A binding with matching key exists in component:
ir.heart.heartproject.utils.di.
modules.FragmentContainerModule_ContributeLoginFr
agmentInjector.LoginFragmentSubcomponent
ir.heart.heartproject.utils.MvpUtils.
LoginContract.Presenter is injected at
ir.heart.heartproject.views.fragments.LoginFragment.mPresenter
ir.heart.heartproject.views.fragments.LoginFragment is injected at
ir.heart.heartproject.views.activities.MainActivity.loginFragment
ir.heart.heartproject.views.activities.MainActivity is injected at
dagger.android.AndroidInjector.inject(T)
component path:
ir.heart.heartproject.utils.di.component.ApplicationComponent ?
ir.heart.heartproject.utils.di.modules.
ActivityBuilder_BindMainActivity.MainActivitySubcomponent
答案 0 :(得分:4)
您可以使用@inject注释LoginFragment的构造函数,当请求一个新实例时,Dagger会构造LoginFragment类的实例并满足其依赖性(例如mPresenter字段)。由于MainActivitySubcomponent无法访问LoginFragmentModule,因此Dagger会为您提供一个无法提供LoginContract.Presenter的错误。如果您使用其他方法为MainActivity提供LoginFragment,而不是使用构造函数注入,则将解决此问题。您应该从LoginFragment构造函数中删除@inject并创建一个模块来提供它,如以下示例所示:
@Module
public class MainModule {
@Provides
public static LoginFragment provideLoginFragment() {
return LoginFragment.newInstance("param1", "param2");
}
}
Dagger技巧:不要对系统实例化它的对象使用构造方法注入。在android中,要在活动和片段中注入依赖关系,您应该使用字段注入方法。