Question

public class HostActivity extends Activity {
    @Inject HostedFragment fragment;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_host);

        ObjectGraph.create(new HostActivityModule()).inject(this);

        if (savedInstanceState == null) {
            getFragmentManager().beginTransaction().add(R.id.fragment_container, fragment).commit();
        }
    }

    public static class HostedFragment extends Fragment{
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            return inflater.inflate(R.layout.fragment_hosted, container, false);
        }
    }

    @Module(injects = HostActivity.class)
    public static class HostActivityModule {
        @Provides @Singleton
        HostedFragment provideHostedFragment() {
            return new HostedFragment();
        }
    }
}

在一个新项目中，我开始使用匕首和嵌套片段，在我的脑海中得到了两个问题。 1.片段是否应注入活动或其他片段？ 2.在配置更改后注入处理娱乐的片段的正确方法是什么？我遇到的问题是在上面的代码中，将创建另一个HostedFragment并将其注入HostActivity。

if (savedInstanceState == null) {
   ObjectGraph.create(new HostActivityModule()).inject(this);
    getFragmentManager().beginTransaction().add(R.id.fragment_container, fragment).commit();
}

修改上述版本可能会避免重复创建HostedFragment，但如果我们需要注射除片段之外的其他注入，则不会在重新创建时注入它们。

任何人都可以帮助我吗？

Answer 1

我提出了一种方法，我是否正确？唯一困扰我的是如果在@Module注入中未指定HostedFragment，我无法从图中获取它。

public class HostActivity extends Activity { private static final String FRAGMENT_TAG =“fragment tag”;

private ObjectGraph objectGraph;
private HostedFragment fragment;
@Inject LocationManager locationManager;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_host);

    // Injecting fields that are required
    objectGraph = ObjectGraph.create(new HostActivityModule(this));
    objectGraph.inject(this);

    // Injecting fragment
    fragment = (HostedFragment) getFragmentManager().findFragmentByTag(FRAGMENT_TAG);
    if (fragment == null) {
        fragment = objectGraph.get(HostedFragment.class);
        getFragmentManager().beginTransaction().add(R.id.fragment_container, fragment, FRAGMENT_TAG).commit();
    }
}

public static class HostedFragment extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_hosted, container, false);
    }
}

@Module(
        injects = {
                HostActivity.class,
                HostedFragment.class
        },
        library = true
)
public static class HostActivityModule {

    private Context mContext;

    public HostActivityModule(Context mContext) {
        this.mContext = mContext;
    }

    @Provides @Singleton HostedFragment provideHostedFragment() {
        return new HostedFragment();
    }

    @Provides @Singleton LocationManager provideLocationManager() {
        return (LocationManager) mContext.getSystemService(LOCATION_SERVICE);
    }
}

}

注入片段和配置更改处理

1 个答案: