kotlin: 用Retrofit访问网络接口

一，安装第三方库

build.gradle.kts中添加

    implementation("com.squareup.retrofit2:retrofit:2.9.0")
    implementation("com.squareup.retrofit2:converter-gson:2.9.0")
    implementation("com.google.code.gson:gson:2.13.0")

然后点击:Sync Now 链接

二，代码：

json.php

model类

package com.example.okdemo2.fragment

//import com.google.gson.annotations.
import com.google.gson.annotations.SerializedName
import java.io.Serializable

open class ApiResponse<T>(
    open val data: T? = null,
    open val code: Int = -1,
    open val msg: String = "",
    open val status: String? = null,
    open val time: String? = null,
    open val error: Throwable? = null,
) : Serializable {
    val isSuccess: Boolean
        get() = code == 200
}

data class UserList(
    @SerializedName("list")
    val `list`: MutableList<UserListItem>,
    @SerializedName("curpage")
    val curPage: Int,
    @SerializedName("total")
    val total: Int,
    @SerializedName("totalpage")
    val totalPage: Int
) : Serializable

data class UserListItem(
    @SerializedName("id")
    val id: Int,
    @SerializedName("name")
    val name: String,
    @SerializedName("image")
    val image: String,
) : Serializable

接口列表:

package com.example.okdemo2.fragment

import retrofit2.Call
import retrofit2.http.Body
import retrofit2.http.GET
import retrofit2.http.POST

interface ApiService {
    @GET("/json.php")
    fun queryUser() : Call<ApiResponse<UserList>>
}

调用retrofit访问接口

        //按钮点击
        binding.getJsonButton.setOnClickListener {
            println("按钮被点击了")

            val retrofit = Retrofit.Builder()
                .baseUrl("http://www.testit.net")
                .addConverterFactory(GsonConverterFactory.create())
                .build()
            val appService = retrofit.create(ApiService::class.java)

            appService.queryUser().enqueue(object: Callback<ApiResponse<UserList>> {
                override fun onResponse(call: Call<ApiResponse<UserList>>, response: Response<ApiResponse<UserList>>) {
                    if (response.isSuccessful) {
                        val user = response.body()
                        if (user?.status == "success") {
                            println("成功")
                            println(user?.data?.list)
                        } else {
                            println("失败")
                        }
                    }
                }

                override fun onFailure(call: Call<ApiResponse<UserList>>, t: Throwable) {
                    println("Retrofit onFailure:${t.message}")
                }
            })
        }

三，运行结果 ：