java - Retrofit 2 请求没有给我数据

Question

我正在尝试通过 Retrofit 2 发送 GET 请求。

但是，该请求没有执行任何操作..

API服务

package com.example.brews.network

import com.jakewharton.retrofit2.adapter.kotlin.coroutines.CoroutineCallAdapterFactory
import com.squareup.moshi.Moshi
import com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory
import kotlinx.coroutines.Deferred
import retrofit2.Retrofit
import retrofit2.converter.moshi.MoshiConverterFactory
import retrofit2.http.GET
import retrofit2.http.Query

/*
    This is the sandbox base url (way less data than production environment)
    When deploying app -> use production base url
 */
private const val BASE_URL = "https://sandbox-api.brewerydb.com/v2/"

/**
 * Build the Moshi object that Retrofit will be using, making sure to add the Kotlin adapter for
 * full Kotlin compatibility.
 */
private val moshi = Moshi.Builder()
    .add(KotlinJsonAdapterFactory())
    .build()

/**
 * Use the Retrofit builder to build a retrofit object using a Moshi converter with our Moshi
 * object.
 */
private val retrofit = Retrofit.Builder()
    .addConverterFactory(MoshiConverterFactory.create(moshi))
    .addCallAdapterFactory(CoroutineCallAdapterFactory())
    .baseUrl(BASE_URL)
    .build()

/**
 * A public interface that exposes the [getProperties] method
 */
interface BreweryApiService {
    /**
     * Returns a Coroutine [Deferred] [List] of [BeerProperty] which can be fetched with await() if
     * in a Coroutine scope.
     * The @GET annotation indicates that the "beers" endpoint will be requested with the GET
     * HTTP method
     */
    @GET("beers/")
    fun getProperties(@Query("?key") key: String):
    // The Coroutine Call Adapter allows us to return a Deferred, a Job with a result
            Deferred<List<BeerProperty>>

}

/**
 * A public Api object that exposes the lazy-initialized Retrofit service
 */
object BreweryApi {
    val retrofitService: BreweryApiService by lazy { retrofit.create(BreweryApiService::class.java) }
}

数据类

package com.example.brews.network

data class BeerProperty(
    val id: Int,
    val name: String
)

填充我的列表的方法

private fun getBeersProperties() {
    coroutineScope.launch {
        var getPropertiesDeferred =
            BreweryApi.retrofitService.getProperties("13e9caaf80adac04dce90ef55600d898")
        try {
            _status.value = BreweryApiStatus.LOADING
            val listResult = getPropertiesDeferred.await()
            _status.value = BreweryApiStatus.DONE
            _properties.value = listResult
        } catch (e: Exception) {
            _status.value = BreweryApiStatus.ERROR
            _properties.value = ArrayList()
        }
    }
}

通过链接检索的 JSON

{ “当前页”:1， “页数”:23， “总结果”:1109， “数据”: [ { “id”:“c4f2KE”， "name": "'穆里肯比尔森啤酒", "nameDisplay": "'穆里肯比尔森啤酒", “酒精度”:“5.5”， “玻璃器皿ID”:4， “风格ID”:98， “是有机的”:“N”， “已退休”:“N” }
] }

我需要检索的是“数据”内的“ID”和“名称”。但是，这是在一个数组中，我不知道如何通过改造来提取它..

Answer 1

您需要有一个 DAO 对象来从 Retrofit 获取 JSON 响应，然后解析 JSON 对象以获得您想要的结果。

因此创建一个像这样的 DAO 对象:-

data class BeerResponse(
  val data: List<BeerProperty>?
)

并将您的服务方法更改为:-

@GET("beers/")
fun getProperties(@Query("?key") key: String):
// The Coroutine Call Adapter allows us to return a Deferred, a Job with a result
        Deferred<BeerResponse>

然后在您的 getBeerProperties 方法中，将其更改为:-

private fun getBeersProperties() {
coroutineScope.launch {
    var getPropertiesDeferred =
        BreweryApi.retrofitService.getProperties("13e9caaf80adac04dce90ef55600d898")
    try {
        _status.value = BreweryApiStatus.LOADING
        val listResult = getPropertiesDeferred.await()
        listResult.data?.let {
            _status.value = BreweryApiStatus.DONE
            _properties.value = it
        } ?: let {
            _status.value = BreweryApiStatus.ERROR
            _properties.value = ArrayList()
        }
    } catch (e: Exception) {
        _status.value = BreweryApiStatus.ERROR
        _properties.value = ArrayList()
    }
}