Otto 和 Dagger 的 NullPointerException

Question

我是 Otto 的新手，我在确定它与 Dagger 依赖注入器和 JobManager 一起运行时遇到了严重的问题。每当我启动我的应用程序时，我都会收到相同的错误消息：

"java.lang.RuntimeException: Unable to resume activity {sdos.juanjosemelero.pruebaormlite2/sdos.juanjosemelero.pruebaormlite2.MainActivity}:
java.lang.NullPointerException: Attempt to invoke virtual method 'void com.squareup.otto.Bus.register(java.lang.Object)' on a null object reference"

[...]

"Caused by java.lang.NullPointerException:
Attempt to invoke virtual method 'void com.squareup.otto.Bus.register(java.lang.Object)' on a null object reference".

它引用的是这一行：

bus.register(this);

这是我的 activity:

public class MainActivity extends ActionBarActivity {

    @Inject Bus bus;   

    @Override
    protected void onResume() {
        super.onResume();
        bus.register(this);
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.inject(this);

    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        bus.unregister(this);
    }
}

这是我的 Dagger 注入模块：

@Module(
    injects = {MainActivity.class},
    library = true
)

public class MyModule {

    private final MyApplication application;

    public MyModule (MyApplication application) {
        this.application = application;
    }

    @Provides
    @Singleton
    MyApplication provideMyApplication() {
        return application;
    }

    @Provides
    @Singleton
    public Bus provideBus (){
        return new Bus(ThreadEnforcer.ANY);
    }
}

还有MyApplicationclass如果有兴趣可以看看：

public class MyApplication extends Application {

    private ObjectGraph objectGraph;
    private static MyApplication application;

    //Constructor
    public MyApplication() {
        application = this;
    }

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

    public void buildObjectGraph() {
        objectGraph = ObjectGraph.create(new MyModule(this));
    }

    public void inject(Object o) {
        objectGraph.inject(o);
    }

    public static MyApplication get() {
        return application;
    }
}

我应该以某种方式初始化 MainActivity 吗？

Answer 1

您没有使用对象图在 onCreate 中注入 MainActivity。就这样。

直接打电话

MyApplication.get().inject(this);

在 MainActivity onCreate() 中。

Otto 和 Dagger 的 NullPointerException

NullPointerException with Otto and Dagger

android

bus

registering

otto

dagger