【问题标题】:Retrofit LiveDataCallAdapter doesn't call function adapt (call)Retrofit LiveDataCallAdapter 不调用函数adapter(调用)
【发布时间】:2019-09-09 20:48:08
【问题描述】:

尝试解决这个问题大约 4 天,请帮助。 我正在使用 rest API(改造)创建一个应用程序,尝试从 Google 示例中实现 LiveDataCallAdapter https://github.com/googlesamples/android-architecture-components/tree/master/GithubBrowserSample,但改造不会调用适配器方法来适应从服务器获取响应。 我只编辑了 NetworkBoundResourse(用于没有 DB 的工作) 尝试放置断点,在我开始回购(登录)后,LiveDataCallAdapter 有趣的适应(call.enequeue 不想开始)调试不要调用

这是我的一段代码,谢谢

提供我的服务实例

@Singleton
   @Provides
   fun provideRetrofit(): BrizSmartTVService {
       return Retrofit.Builder()
           .baseUrl(baseUrl)
           .addConverterFactory(GsonConverterFactory.create())
           .addCallAdapterFactory(LiveDataCallAdapterFactory())
           .build()
           .create(BrizSmartTVService::class.java)
   }

有我的 LiveDataCallAdapterFactory 和 LiveDataCallAdapter

class LiveDataCallAdapterFactory : Factory() {
    override fun get(
        returnType: Type,
        annotations: Array<Annotation>,
        retrofit: Retrofit
    ): CallAdapter<*, *>? {
        if (getRawType(returnType) != LiveData::class.java) {
            return null
        }
        val observableType = getParameterUpperBound(0, returnType as ParameterizedType)
        val rawObservableType = getRawType(observableType)
        if (rawObservableType != ApiResponse::class.java) {
            throw IllegalArgumentException("type must be a resource")
        }
        if (observableType !is ParameterizedType) {
            throw IllegalArgumentException("resource must be parameterized")
        }
        val bodyType = getParameterUpperBound(0, observableType)
        return LiveDataCallAdapter<Any>(bodyType)
    }
}

class LiveDataCallAdapter<R>(private val responseType: Type) :
    CallAdapter<R, LiveData<ApiResponse<R>>> {

    override fun responseType() = responseType

    override fun adapt(call: Call<R>): LiveData<ApiResponse<R>> {
        return object : LiveData<ApiResponse<R>>() {
            private var started = AtomicBoolean(false)
            override fun onActive() {
                super.onActive()
                if (started.compareAndSet(false, true)) {
                    Log.d("TAG", ": onActive Started ");
                    call.enqueue(object : Callback<R> {
                        override fun onResponse(call: Call<R>, response: Response<R>) {
                            Log.d("TAG", ":    $response");
                            postValue(ApiResponse.create(response))
                        }

                        override fun onFailure(call: Call<R>, throwable: Throwable) {
                            Log.d("TAG", ":    ${throwable.localizedMessage}");
                            postValue(ApiResponse.create(throwable))
                        }
                    })
                }
            }
        }
    }
}

有我的 NetworkBoundResource(仅适用于网络)


abstract class NetworkBoundResource<RequestType> {

    private val result = MediatorLiveData<Resource<RequestType>>()

    init {
        setValue(Resource.loading(null))
        fetchFromNetwork()
    }

    @MainThread
    private fun setValue(newValue: Resource<RequestType>) {
        if (result.value != newValue) {
            result.value = newValue
        }
    }

    private fun fetchFromNetwork() {
        val apiResponse = createCall()
        result.addSource(apiResponse) { response ->
            result.removeSource(apiResponse)

            when (response) {
                is ApiSuccessResponse -> {
                    setValue(Resource.success(processResponse(response)))
                }

                is ApiErrorResponse -> {
                    onFetchFailed()
                    setValue(Resource.error(response.errorMessage, null))

                }
            }
        }
    }

    protected fun onFetchFailed() {
    }

    fun asLiveData() = result as LiveData<Resource<RequestType>>

    @WorkerThread
    protected open fun processResponse(response: ApiSuccessResponse<RequestType>) = response.body

    @MainThread
    protected abstract fun createCall(): LiveData<ApiResponse<RequestType>>
}

我的回购类


@Singleton
class AuthApiRepo @Inject constructor(
    val apiService: BrizSmartTVService
) {

    fun authLoginPass(login: String, password: String): LiveData<Resource<AuthResponse>> {
        return object : NetworkBoundResource<AuthResponse>() {

            override fun createCall(): LiveData<ApiResponse<AuthResponse>> {
                val authLogPassBody = AuthLogPassBody(login,password,"password")
                Log.d("TAG", ":   $authLogPassBody");
                return apiService.authLoginPass(authLogPassBody)
            }

        }.asLiveData()
    }
}

还有我的 AuthResponse 类


class AuthResponse {
    @SerializedName("token_type")
    var tokenType: String? = null
    @SerializedName("access_token")
    var accessToken: String? = null
    @SerializedName("refresh_token")
    var refreshToken: String? = null
    @SerializedName("user_id")
    var userId: String? = null
    @SerializedName("expires_in")
    var expiresIn: Long = 0
    @SerializedName("portal_url")
    var portalUrl: String? = null
}

我开始调用的 ViewModel 类


class AuthViewModel @Inject constructor(private val authApiRepo: AuthApiRepo) : ViewModel() {

    private var _isSigned = MutableLiveData<Boolean>()
    val isSigned: LiveData<Boolean>
        get() = _isSigned


    fun signIn(login: String, password: String) {
        authApiRepo.authLoginPass(login, password)
        val authRespons =  authApiRepo.authLoginPass(login, password)
        Log.d("TAG", ":   " +   authRespons.value.toString());
        //here will by always data null and status LOADING
    }

    override fun onCleared() {
        super.onCleared()
    }
}

【问题讨论】:

  • 你有什么错误吗?或者你在你的 logcat 中看到了什么?
  • 什么都没有,没有任何错误或 logcat 条目

标签: android kotlin retrofit android-livedata


【解决方案1】:

所以伙计们,我终于找到了解决方案。对于在 MVVM(实时数据)主题中经验丰富的人来说,这非常简单,但我是 MVVM 的初学者,当我来到这里时,我的大脑爆炸了。 所以,问题是我从 ViewModel 订阅了 Repo livedata,而不是从 View(在我的例子中是 Fragment)。在我锁定了 livedata 观察者链后,View - ViewModel - Repo - Service - 一切正常。谢谢大家

【讨论】:

  • 非常感谢!!我从没想过这个问题会在完全相同的情况下出现在stackoverflow上。大声笑(也使用谷歌示例)
  • 这对我来说没有意义..我面临同样的问题。我希望通过单击按钮获得 API 的响应.. 但是如果我直接观察响应的实时数据,一旦我的活动启动,它就会被调用
  • 您好,您能否详细解释一下,因为我面临同样的问题。我是 MVVM 的初学者,我找不到合适的解决方案
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