Android Kotlin Retrofit手机充值API调用失败问题求助

作为编程新手，在Android平台使用Kotlin+Retrofit开发手机充值功能时，调用POST类型API出现异常，代码无法正常运行。以下是相关信息及问题排查：

1. 相关代码片段 #

PHP API查询语句 #

query('select mt.translationID,mt.mobile,mt.amount, mt.operatorCodeTimestamp as rechargedate, mt.status from mst_translation mt join agent_users mu on mu.agent_id=mt.userID where mu.mobile="'.$userID.'" and mu.domainName="'.$domain.'"')->result();

Retrofit接口定义 #

interface ApiEndPoint {
    @POST("api/Recharge/make")
    fun rechargeMobile(
        @Query("userId") userId: String,
        @Query("domain") domain: String,
        @Body request: RechargeRequest
    ): Call<RechargeResponce?>?
}

Main Activity代码 #

class MoneyTransfer : AppCompatActivity() {

    val binding by lazy{
        ActivityMoneyTransferBinding.inflate(layoutInflater)
    }
    private lateinit var apiEndPoint : ApiEndPoint
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(binding.root)

        initBlock()

        binding.proceed.setOnClickListener {
            dataSetup()
        }
    }

    fun dataSetup(){
        val mobileRechargeRequest = RechargeRequest(
            operatorCode = binding.operatorCode.text.toString(),
            userID = "2050",
            userpin = "1234",
            amount = binding.mobileNumber.text.toString(),
            servicenumber = binding.mobileNumber.text.toString(),
            domain = "www.pay2kart.com",
            servicetype = "MOBILE"
        )

        val response = apiEndPoint.rechargeMobile("2050", "www.pay2kart.com",mobileRechargeRequest)

        response!!.enqueue(object : Callback<RechargeResponce?> {
            override fun onResponse(
                call: Call<RechargeResponce?>,
                response: Response<RechargeResponce?>
            ) {
                try {
                    if (response != null) {
                        Log.e("message", response.message().toString())
                        Toast.makeText(
                            this@MoneyTransfer,
                            response.message().toString(),
                            Toast.LENGTH_LONG
                        ).show()
                    }
                } catch (e: Exception) {
                    Toast.makeText(
                        this@MoneyTransfer,
                        "Some NetWork Error Has been found ... ",
                        Toast.LENGTH_LONG
                    ).show()
                }
            }

            override fun onFailure(call: Call<RechargeResponce?>, t: Throwable) {
                Toast.makeText(this@MoneyTransfer, "Failed ...", Toast.LENGTH_LONG).show()
            }
        })
    }

    private fun initBlock() {
        var retrofit = ServerConnection.getConnection()
        if (retrofit != null) {
            apiEndPoint = retrofit.create(ApiEndPoint::class.java)
        }
    }
}

2. API信息 #

API地址：https://www.pay2kart.com/pay2kart_api_testing/Services/index.php/api/Recharge/make

3. Postman测试成功的请求体 #

{
"operatorCode":"102",
"userID":"2050",
"userpin":"1234",
"servicenumber":"8878840990", 
"domain":"www.pay2kart.com",
"servicetype":"MOBILE"
}

问题排查与修正 #

核心错误点 #

1. 参数传递方式不匹配：Postman测试时所有参数都放在请求Body中，但你的Retrofit接口把userId和domain作为URL Query参数传递，与API期望的接收方式不符，API会从Body读取参数，忽略Query参数导致校验失败。
2. 请求体结构冗余：RechargeRequest中已经包含userID和domain，却额外通过@Query传递，造成参数重复；同时你给amount赋值了手机号输入框的内容，而Postman成功请求里并不存在amount字段，导致请求体结构不匹配。
3. 空安全风险：使用response!!强制非空，一旦接口返回null会触发空指针异常。

修正方案 #

1. 修改Retrofit接口：移除@Query参数，仅保留@Body传递完整请求体：

interface ApiEndPoint {
    @POST("api/Recharge/make")
    fun rechargeMobile(
        @Body request: RechargeRequest
    ): Call<RechargeResponce?>
}

2. 调整RechargeRequest类：删除多余的amount字段，确保所有字段名、大小写与Postman成功请求的JSON完全一致。

3. 修正API调用逻辑：仅传递RechargeRequest对象，去掉冗余的Query参数：

val response = apiEndPoint.rechargeMobile(mobileRechargeRequest)

4. 优化空安全与调试信息：

response?.enqueue(object : Callback<RechargeResponce?> {
    override fun onResponse(call: Call<RechargeResponce?>, response: Response<RechargeResponce?>) {
        Log.e("API Code", response.code().toString())
        Log.e("API Body", response.body().toString())
        Toast.makeText(this@MoneyTransfer, "Code: ${response.code()}, Msg: ${response.message()}", Toast.LENGTH_LONG).show()
    }

    override fun onFailure(call: Call<RechargeResponce?>, t: Throwable) {
        Log.e("API Error", t.message.toString())
        Toast.makeText(this@MoneyTransfer, "Error: ${t.message}", Toast.LENGTH_LONG).show()
    }
})

5. 检查Retrofit配置：确保初始化时添加了JSON转换器（如GsonConverterFactory），否则无法正确序列化请求体：

Retrofit.Builder()
    .baseUrl("https://www.pay2kart.com/pay2kart_api_testing/Services/index.php/")
    .addConverterFactory(GsonConverterFactory.create())
    .build()

内容的提问来源于stack exchange，提问作者Sabuj Ahmed