如何在Jetpack Compose中通过Retrofit多参数GET请求获取词汇数据

我正在开发一款面向初学者的英语学习APP，现在需要通过Retrofit发起GET请求，携带Level和Unit两个查询参数，从数据库获取对应词汇数据。接口示例为https://adeega.xisaabso.online/Api/Article_vocabulary.php?Level=1&Unit=1，以下是我的现有代码，求解决方案：

Vocabulary_Api.kt #

const val Vocabulary = "https://adeega.xisaabso.online/Api/"

interface getVocabularies {
   @GET("Article_vocabulary.php")
   fun getVocabularies(): Call<Vocabularies>
}

object getVocabulariesInstance {
   val getVocabulariesSections: getVocabularies

   init {
      val retrofit = Retrofit.Builder()
         .baseUrl(Vocabulary)
         .addConverterFactory(GsonConverterFactory.create())
         .build()
      getVocabulariesSections = retrofit.create(getVocabularies::class.java)
   }
}

Vocabulary.kt #

val users = getVocabulariesInstance.getVocabulariesSections.getVocabularies()

val data = remember { mutableStateOf(Vocabularies()) }
users.enqueue(object: Callback<Vocabularies> {
   override fun onResponse(
      call: Call<Vocabularies>,
      response: Response<Vocabularies>
   ) {
      val userData = response.body()
      if(userData != null) {
         data.value = userData
      }
   }
   override fun onFailure(call: Call<Vocabularies>, t: Throwable) {
      Toast.makeText(context, t.toString(), Toast.LENGTH_SHORT).show()
   }
})


LazyColumn(
   contentPadding = PaddingValues(
      horizontal = 12.dp,
      /*vertical = 0.dp*/
   ),
   verticalArrangement = Arrangement.spacedBy(10.dp)
) {
   items(data.value) { item ->
      Cards_Vocabulary(data = item, navController)
      //Divider(color = Color.Gray, thickness = 1.dp)
   }
} // END LazyColumn

database.php #

if(!empty($_GET['Level']) && !empty($_GET['Unit'])) {

    $Level = (int)$_GET['Level'];
    $Unit  = (int)$_GET['Unit'];


    $Article = $pdo->prepare("SELECT * FROM App_vocabularies 
                                WHERE LevelID = ? AND UnitID = ?");
    $Article->bindParam(1, $Level);
    $Article->bindParam(2, $Unit);
    $Article->execute();
    $Article = $Article->fetchAll(PDO::FETCH_OBJ);
        echo json_encode($Article);

}

1. 修改Retrofit接口，添加查询参数 #

当前接口未传递Level和Unit参数，需要通过@Query注解添加这两个参数，同时调整返回类型为列表（PHP接口返回的是词汇数组）：

const val Vocabulary = "https://adeega.xisaabso.online/Api/"

// 接口名遵循大驼峰规范，改为VocabularyApi
interface VocabularyApi {
   @GET("Article_vocabulary.php")
   fun getVocabularies(
       @Query("Level") level: Int,
       @Query("Unit") unit: Int
   ): Call<List<VocabularyItem>>
}

object VocabularyApiInstance {
   val api: VocabularyApi

   init {
      val retrofit = Retrofit.Builder()
         .baseUrl(Vocabulary)
         .addConverterFactory(GsonConverterFactory.create())
         .build()
      api = retrofit.create(VocabularyApi::class.java)
   }
}

2. 创建单个词汇的数据模型类 #

根据数据库字段创建VocabularyItem类，确保属性名和JSON返回的字段一致：

data class VocabularyItem(
    val id: Int,
    val LevelID: Int,
    val UnitID: Int,
    val word: String,
    val meaning: String,
    // 添加其他数据库对应的字段
)

3. 调整接口调用逻辑 #

传入Level和Unit参数，同时将状态变量改为列表类型：

// 示例值，实际可从导航参数或用户选择获取
val targetLevel = 1
val targetUnit = 1

val users = VocabularyApiInstance.api.getVocabularies(targetLevel, targetUnit)

val data = remember { mutableStateOf(emptyList<VocabularyItem>()) }
users.enqueue(object: Callback<List<VocabularyItem>> {
   override fun onResponse(
      call: Call<List<VocabularyItem>>,
      response: Response<List<VocabularyItem>>
   ) {
      val userData = response.body()
      if(userData != null) {
         data.value = userData
      } else {
          Toast.makeText(context, "未获取到对应词汇数据", Toast.LENGTH_SHORT).show()
      }
   }
   override fun onFailure(call: Call<List<VocabularyItem>>, t: Throwable) {
      Toast.makeText(context, "请求失败：${t.message}", Toast.LENGTH_SHORT).show()
   }
})

4. 适配LazyColumn数据源 #

因为data现在是列表类型，直接使用items(data.value)即可：

LazyColumn(
   contentPadding = PaddingValues(
      horizontal = 12.dp,
      /*vertical = 0.dp*/
   ),
   verticalArrangement = Arrangement.spacedBy(10.dp)
) {
   items(data.value) { item ->
      Cards_Vocabulary(data = item, navController)
      //Divider(color = Color.Gray, thickness = 1.dp)
   }
} // END LazyColumn

额外优化建议 #

给PHP接口添加参数缺失的处理逻辑，方便客户端调试：

if(!empty($_GET['Level']) && !empty($_GET['Unit'])) {
    // 现有查询逻辑...
} else {
    echo json_encode(array("error" => "Level或Unit参数缺失"));
}

内容的提问来源于stack exchange，提问作者Mohammed