Dagger 2 Presenter 注入返回空值

Question

我正在尝试将 Dagger 2 添加到我的 Android 项目中。我的应用程序有以下屏幕

登录扩展基础 activity
导航 Activity 扩展基础 activity
MW Activity 扩展导航 Activity

Presenter 注入在登录和导航中工作正常 activity 而在 MW activity 中它 return null

黄油刀在 MW 中也不工作 Activity 而在其他活动中工作正常

以下是我的 classes 申请class

public class abcApplication extends Application {
    ApplicationComponent mApplicationComponent;

    @Override
    public void onCreate() {
        super.onCreate();


        mApplicationComponent = DaggerApplicationComponent.builder()
                .applicationModule(new ApplicationModule(this))
                .build();
        mApplicationComponent.inject(this);
    }

    public static abcApplication get(Context context) {
        return (abcApplication) context.getApplicationContext();
    }

    public ApplicationComponent getComponent() {
        return mApplicationComponent;
    }

    // Needed to replace the component with a test specific one
    public void setComponent(ApplicationComponent applicationComponent) {
        mApplicationComponent = applicationComponent;
    }


}

基础activity

public class BaseActivity extends AppCompatActivity {
    private ActivityComponent mActivityComponent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }


    public ActivityComponent activityComponent() {
        if (mActivityComponent == null) {
            mActivityComponent = DaggerActivityComponent.builder()
                    .activityModule(new ActivityModule(this))
                    .applicationComponent(abcApplication.get(this).getComponent())
                    .build();
        }
        return mActivityComponent;
    }

}

导航Activity

public class NavigationActivity extends BaseActivity implements NavigationView {

    @Inject
    DataClient mDataClient;

    @Bind(R.id.drawer_layout)
    protected DrawerLayout mDrawerLayout;
    @Bind(R.id.navList)
    ExpandableListView mExpandableListView;

    private ActionBarDrawerToggle mDrawerToggle;
    private String mActivityTitle;
    private ExpandableListAdapter mExpandableListAdapter;
    private List<String> mExpandableListTitle;
    private Map<String, List<String>> mExpandableListData;

    private Map<String, String> activityMap;

    private int lastExpandedPosition = -1;

    @Inject
    NavigationPresenter navigationPresenter;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_navigation);
        activityComponent().inject(this);
        ButterKnife.bind(this);
        navigationPresenter.attachView(this);


        }
    @Override
    protected void onDestroy() {
    super.onDestroy();
    navigationPresenter.detachView();
    }
        }

兆瓦 Activity

public class MWActivity extends NavigationActivity implements MWView{
    private MWPagerAdapter mMWPagerAdapter;


    @Inject
    MWPresenter MWPresenter;

    private ViewPager mViewPager;


    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        LayoutInflater inflater = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        DrawerLayout mDrawer = (DrawerLayout) findViewById(R.id.drawer_layout);

        ButterKnife.bind(this);

        MWPresenter.attachView(this);
        MWPresenter.getMarketData();
        }

    }

Logcat : 致命例外：主要进程：com.abc.xyz，PID：21542

java.lang.RuntimeException: 无法启动 activity ComponentInfo{com.abc.xyz/com.abc.trading.xyz.ui.main.mw.view.MWActivity}: java.lang.NullPointerException 在 android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2318) 在 android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2396)

@PreActivity
@Component(dependencies = ApplicationComponent.class, modules = ActivityModule.class)

    public interface ActivityComponent {

        void inject(LoginActivity loginActivity);
        void inject(NavigationActivity navigationActivity);
        void inject(MWActivity mWActivity);
        void inject(MWTabFragment mWTabFragment);
        void inject(MWDetailsActivity mWDetailsActivity);


    }

Answer 1

Activity Component was not injected activityComponent().inject(this); in MW Activity

public class MWActivity extends NavigationActivity implements MWView{
    private MWPagerAdapter mMWPagerAdapter;


    @Inject
    MWPresenter MWPresenter;

    private ViewPager mViewPager;


    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        LayoutInflater inflater = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        activityComponent().inject(this);
        DrawerLayout mDrawer = (DrawerLayout) findViewById(R.id.drawer_layout);

        ButterKnife.bind(this);

        MWPresenter.attachView(this);
        MWPresenter.getMarketData();
        }

    }

Activity组件（基础Activity）

 public class BaseActivity extends AppCompatActivity {
    private ActivityComponent mActivityComponent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }


    public ActivityComponent activityComponent() {
        if (mActivityComponent == null) {
            mActivityComponent = DaggerActivityComponent.builder()
                    .activityModule(new ActivityModule(this))
                    .applicationComponent(OmsApplication.get(this).getComponent())
                    .build();
        }
        return mActivityComponent;
    }

}

Answer 2

您手头有 2 个关于超/子类型的问题。

Butterknife not support injection to super types
匕首确实

如前所述，要解决问题 2，您需要在 MWActivity 中调用 inject，而要使用 Butterknife，您需要在 super [=26= 中使用 ViewHolder 模式] 绑定/注入字段，因为它只会注入 MWActivity 而不是 NavigationActivity.

Dagger 2 Presenter 注入返回空值

Dagger 2 presenter injection returning null

android

dependency-injection

dagger-2

butterknife