我是Otto的新手,我在与Dagger依赖注入器和JobManager一起完成其功能时遇到了严重的麻烦.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".

它引用的线是这一行：

bus.register(this);

这是我的活动：

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);
    }
}

这是我的匕首注射模块：

@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);
    }
}

和MyApplication类一样,有趣的是看看它：

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;
    }
}

我想以某种方式初始化MainActivity？

解决方法:

您没有使用对象图在onCreate中注入MainActivity.就这样.

打电话吧

MyApplication.get().inject(this);

在MainActivity onCreate()中.