Question

我正在尝试重构我的代码，所以我在想Dagger2来解决我的问题。我已创建AppComponent来存储我的所有Singletons：

@AppScope
@Component(
        modules = {
                AppModule.class,
                // more here...
        }
)
public interface AppComponent {

    Context exposeContext();

    CmdComponent newCmdComponent(CmdModule module);

    // ... few injections here
}

我的AppModule：

@Module
public class AppModule {

    private Context context;

    public AppModule(Context context) {
        this.context = context;
    }

    // ... provide appContext etc.

    @AppScope @Provides
    MyClass provideMyClass() {
        Log.i("DAGGER", "provideMyClass: ");
        return new MyClass();
    }

}

我在我的Application课程中注入了这个：

public class App extends Application {

    private static AppComponent component;

    @Override
    public void onCreate() {
        super.onCreate();
        component = DaggerAppComponent.builder()
                .appModule(new AppModule(app))
                .build();
    }

    public static AppComponent getAppComponent() {
        return component;
    }
}

然后我的子组件CmdComponent具有不同的@Scope

@CmdScope
@Subcomponent(
        modules = {
                CmdModule.class
        }
)
public interface CmdComponent {
    void inject(Cmd cmd);
}

现在我将依赖项注入我的Cmd实例中，如：

@Inject MyClass myClass;

public Cmd() {
    App.getAppComponent()
            .newCmdComponent(new CmdModule())
            .inject(this);
}

不幸的日志：Log.i("DAGGER", "provideMyClass: ");和MyClass构造函数中的日志多次显示...所以每次都会获得MyClass的新实例。如何告诉Dagger每次都给我相同的实例（创建一次）？

Answer 1

Ok. I solve my issue. The solution is simple. My AppScope was created wrong. For some reason, I thought that annotation works like inheritance.

My custom annotation was like:

@Singleton
@Retention(RetentionPolicy.RUNTIME)
public @interface AppScope {
}

and Dagger thought that my component is unscoped.. It should be like:

@Scope
@Retention(RetentionPolicy.RUNTIME)
public @interface AppScope {
}

Answer 2

.newCmdComponent(new CmdModule())怎么样？为什么这样做，每次创建一个新模块？该组件已经附加了一个模块，您可以在创建组件时设置该模块。

Dagger 2 MyClass的单个实例

2 个答案:

Dagger 2 MyClass的单​​个实例

2 个答案:

Dagger 2 MyClass的单个实例