使用Retrofit+Moshi调用API无响应，Android新闻App求助

我正在学习Android开发，尝试搭建一个简易新闻App，但已卡壳3天无法从服务器获取JSON响应。怀疑Retrofit调用存在问题却找不到原因，Logcat中无响应输出（已替换个人API密钥）。

相关代码 #

private const val BASE_URL = "https://newsapi.org"

private val moshi = Moshi.Builder()
    .add(KotlinJsonAdapterFactory())
    .build()

private val retrofit = Retrofit.Builder()
    .addConverterFactory(MoshiConverterFactory.create(moshi))
    .baseUrl(BASE_URL)
    .build()

interface CallNewsApi {
    @GET("/v2/top-headlines")
    suspend fun getHeadlines(
        @Query("apiKey") key: String,
        @Query("category") category: String,
        @Query("country") country: String
    ): Response<NewsApiResponse>
}

object NewsApi {
    val retrofitService: CallNewsApi by lazy {
        retrofit.create(CallNewsApi::class.java)
    }
}

data class NewsApiResponse(
    var status: String,
    var totalResults: Int,
    var articles: List<NewsHeadlines>
)

data class NewsHeadlines(
    var source: Source,
    var author: String,
    var title: String,
    var description: String,
    var url: String,
    var urlToImage: String,
    var publishedAt: String,
    var content: String
)

data class Source(
    var id: String,
    var name: String
)

class NewsViewModel : ViewModel() {
    private val _newsList = MutableLiveData<List<NewsHeadlines>>()
    val status: LiveData<List<NewsHeadlines>> = _newsList
    init {
        getNewsLines()
    }
    private fun getNewsLines() {
        viewModelScope.launch {
            try {
                Log.d("ViewModel"," before retrofit")
                val call = NewsApi.retrofitService.getHeadlines(
                    "myApiKey",
                    "sports",
                    "il"
                )
                Log.d("ViewModel", call.body().toString())
            } catch (e: java.lang.Exception) {
                _newsList.value = listOf()
            }
        }
    }
}

1. 未处理响应状态与错误信息 #

当前代码仅打印响应体，未检查请求是否成功，也未捕获并打印请求失败的状态码、错误信息及异常栈，导致无法定位问题。修改getNewsLines方法：

private fun getNewsLines() {
    viewModelScope.launch {
        try {
            Log.d("ViewModel"," before retrofit")
            val response = NewsApi.retrofitService.getHeadlines(
                "myApiKey",
                "sports",
                "il"
            )
            if (response.isSuccessful) {
                Log.d("ViewModel", "响应成功: ${response.body().toString()}")
                response.body()?.let {
                    _newsList.value = it.articles
                } ?: Log.e("ViewModel", "响应体为空")
            } else {
                Log.e("ViewModel", "请求失败，状态码: ${response.code()}")
                response.errorBody()?.let {
                    Log.e("ViewModel", "错误详情: ${it.string()}")
                }
            }
        } catch (e: Exception) {
            Log.e("ViewModel", "请求异常", e)
            _newsList.value = listOf()
        }
    }
}

2. 数据类字段未兼容空值 #

NewsAPI返回的部分字段（如author、source.id、urlToImage）可能为null，当前数据类使用非空类型会导致Moshi解析抛出异常。修改数据类为可空类型：

data class NewsHeadlines(
    var source: Source,
    var author: String?,
    var title: String,
    var description: String?,
    var url: String,
    var urlToImage: String?,
    var publishedAt: String,
    var content: String?
)

data class Source(
    var id: String?,
    var name: String
)

3. 基础配置检查 #

• 确认AndroidManifest.xml已添加网络权限：

  <uses-permission android:name="android.permission.INTERNET" />
  

• 用浏览器/Postman直接访问接口链接（替换真实API密钥），验证接口本身是否能返回有效数据：
  https://newsapi.org/v2/top-headlines?apiKey=你的密钥&category=sports&country=il
• 检查API密钥有效性：确认密钥未过期、未超出请求次数限制，且允许当前App包名访问。

内容的提问来源于stack exchange，提问作者Sami Kassoum