Question

我正在尝试将Dagger 2添加到我的Android项目中。我的申请有以下屏幕

登录扩展基本活动
导航活动扩展基本活动
MW活动范围导航活动

Presenter Injection在登录和导航活动中工作正常，而在MW活动中它返回null

Butter Knife也没有在MW活动中工作，在其他活动中工作正常

以下是我的课程申请类

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;
    }


}

基础活动

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;
    }

}

导航活动

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();
    }
        }

MW活动

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：致命异议：主要处理：com.abc.xyz，PID：21542

java.lang.RuntimeException：无法启动活动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

您手头有2个关于超级/子类型的问题。

Butterknife not support injection to super types
Dagger做not support injection to sub types

正如已经指出的，要解决2.你需要在你的inject中调用MWActivity，并使用Butterknife你需要在超类中使用ViewHolder模式来绑定/注入字段，因为它只会注入MWActivity而不是NavigationActivity。

Answer 2

活动组件未注入activityComponent（）。inject（this）; 在MW活动中

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();
        }

    }

ActivityComponent（基本活动）

 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;
    }

}

Dagger 2主持人注射返回null

2 个答案: