android - 方形/ Dagger 。安卓。 java.lang.StackOverflowError 错误

Question

尝试为 Android 使用 Dagger 依赖注入(inject)器。这是扩展的应用程序类:

public class MyApplication extends Application {

    private ObjectGraph objectGraph;

    protected List<Object> getModules() {
        List<Object> objectArrayList = new ArrayList<Object>();

        objectArrayList.add(new AndroidModule(this));
        objectArrayList.add(new DeviceModule());

        return objectArrayList;
    }

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

        objectGraph = ObjectGraph.create(getModules().toArray());
    }

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

这是我的模块:

安卓模块

@Module(library = true)
public class AndroidModule {
    private final MyApplication myApplication;

    public AndroidModule(MyApplication myApplication) {
        this.myApplication = myApplication;
    }

    @Provides
    @Singleton
    @ForApplication
    public Context provideApplicationContext() {
        return myApplication.getApplicationContext();
    }

    @Provides
    @Singleton
    public LocationManager provideLocationManager() {
        return (LocationManager)myApplication.getSystemService(Context.LOCATION_SERVICE);
    }

    @Provides
    public NetworkInfo provideNetworkInfo() {
        ConnectivityManager connectivityManager = (ConnectivityManager)myApplication.getSystemService(Context.CONNECTIVITY_SERVICE);
        return connectivityManager.getActiveNetworkInfo();
    }
}

设备模块

 @Module(injects = MainActivity.class, complete = false, library = true)
public class DeviceModule {

    @Provides
    public SystemValidator provideSystemValidator() {
        return new AndroidSystemValidator();
    }

    @Provides
    public Device provideDevice(SystemValidator systemValidator) {
        return new Device(systemValidator);
    }
}

设备类

public class Device {
    private final SystemValidator systemValidator;

    @Inject
    public Device(SystemValidator systemValidator) {
        this.systemValidator = systemValidator;
    }

    public void validate() {
        boolean isGPSTurnedOn = systemValidator.isGPS();
        boolean isNetworkActive = systemValidator.isNetwork();
    }
}

SystemValidator 类

public class AndroidSystemValidator implements SystemValidator {
    @Inject
    LocationManager locationManager;

    @Inject
    NetworkInfo networkInfo;

    @Override
    public boolean isNetwork() {
        return (null != networkInfo && (networkInfo.getType() == ConnectivityManager.TYPE_MOBILE));
    }

    @Override
    public boolean isGPS() {
        return locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
    }
}

这段成功编译，但在运行时我得到 java.lang.StackOverflowError试图注入(inject) MainActivity对象到 ObjectGraph

java.lang.StackOverflowError
        at com.xxxx.app.modules.system.DeviceModule$$ModuleAdapter$ProvideDeviceProvidesAdapter.get(DeviceModule$$ModuleAdapter.java:77)
        at com.xxxx.app.modules.system.DeviceModule$$ModuleAdapter$ProvideDeviceProvidesAdapter.get(DeviceModule$$ModuleAdapter.java:113)
        at com.xxxx.app.modules.system.DeviceModule$$ModuleAdapter$ProvideDeviceProvidesAdapter.get(DeviceModule$$ModuleAdapter.java:77)
        at com.xxxx.app.modules.system.DeviceModule$$ModuleAdapter$ProvideDeviceProvidesAdapter.get(DeviceModule$$ModuleAdapter.java:113)
        at com.xxxx.app.modules.system.DeviceModule$$ModuleAdapter$ProvideDeviceProvidesAdapter.get(DeviceModule$$ModuleAdapter.java:77)
        at com.xxxx.app.modules.system.DeviceModule$$ModuleAdapter$ProvideDeviceProvidesAdapter.get(DeviceModule$$ModuleAdapter.java:113)

已编辑:

代码已被可行的解决方案更改，但即使 LocationManager和 NetworkInfo对象标记为 @Inject , 是 null。试图告诉AndroidModule通过添加 injects = AndroidSystemValidator.class 放置这些对象的位置但没有成功。如何在不创建参数化构造函数的情况下注入(inject)这些对象？

Answer 1

你有一个循环依赖

@Provides
public Device provideDevice(Device device) {
    return device;
}

当 Dagger 尝试获取 Device 实例以用作 provideDevice 方法的参数时，它会一次又一次地为其调用 provideDevice StackOverflowError 发生。但这只是我的假设。