Kotlin版封装网络请求（MVVM+Flow+Retrofit2+Coroutine协程）

1.在activity调用方式

   
class MainActivity : BaseActivity() {

    private val viewModel: UserViewModel by viewModels()  
    private val adapter: UserAdapter by lazy { UserAdapter() }
  override fun initView(savedInstanceState: Bundle?) {
      initNetworkObserver()
        initViewObserver()
        //网络请求（这里是下拉刷新）
        mBindingView.smartRefresh.setOnRefreshListener {
            lifecycleScope.launch {
                viewModel.searchUser()

            }
        }

    }


  //网络请求监听
    private fun initNetworkObserver() {
        lifecycleScope.launch {
            viewModel.userResult.collect {
                adapter.setList(listOf(it))
                mBindingView.smartRefresh.finishRefresh()

            }
        }
    }

    //视图事件监听
    private fun initViewObserver() {
        viewModel.viewEvent.observeEvent(getParentActivity()) {
            when (it) {
                ViewEvent.DismissDialog -> {
                }

                else -> {

                }
            }
        }


    }

2. ViewMode写法

class UserViewModel(application: Application) : AndroidViewModel(application) {
     
    //视图
    private val _viewEvent: SharedFlowEvents = SharedFlowEvents()
    val viewEvent = _viewEvent.asSharedFlow()

    //数据
    private val _userResult: MutableSharedFlow = MutableSharedFlow()
    val userResult = _userResult.asSharedFlow()

     suspend fun searchUser() {
        viewModelScope.launch {
            flow {
                //调用请求方法
                val data = Api.api.getUser()
                if (data.data != null) {
                    _userResult.emit(data.data!!)
                } else {
                    _viewEvent.setEvent(ViewEvent.ShowToast("查询失败"))
                }
                _viewEvent.setEvent(ViewEvent.DismissDialog)
            }.onStart {
                // delay(2000)
                _viewEvent.setEvent(ViewEvent.ShowDialog)
            }.catch { ex ->
                //当网络请求尚未完成，且抛出了error，则返回Error出去
                val networkResult = call(ex)
                LogUtil.d(networkResult.toString())
                _viewEvent.setEvent(ViewEvent.DismissDialog, ViewEvent.ShowToast("登录失败:${networkResult.second}"))
            }.collect()
        }

    }
}

3.请求封装Api类

package com.ceshi.network

import android.annotation.SuppressLint
import com.ceshi.BuildConfig
import com.ceshi.config.ApiConfig

import okhttp3.OkHttpClient
import okhttp3.logging.HttpLoggingInterceptor
import retrofit2.Retrofit
import retrofit2.converter.gson.GsonConverterFactory
import retrofit2.converter.scalars.ScalarsConverterFactory
import java.security.*
import java.security.cert.X509Certificate
import java.util.concurrent.TimeUnit
import javax.net.ssl.*

/**
 * "ht" 创建
 * 界面名称以及功能:网络请求Retrofit2+Coroutine(协程)
 */
object Api {
    private const val DEFAULT_TIMEOUT: Long = 30
    val api: ApiService by lazy {
        //支持RxJava2
        val retrofit = Retrofit.Builder().baseUrl(ApiConfig.BaseUrl)
            .addConverterFactory(ScalarsConverterFactory.create()) //添加ScalarsConverterFactory支持
            .addConverterFactory(GsonConverterFactory.create())//可以接收自定义的Gson，当然也可以不传
            .client(unsafeOkHttpClient)
            .build()
        return@lazy retrofit.create(ApiService::class.java)
    }

    // Install the all-trusting trust manager TLS
    private val unsafeOkHttpClient: OkHttpClient
        get() = try {
            // Install the all-trusting trust manager TLS
            val sslContext = SSLContext.getInstance("TLS")
            sslContext.init(null, trustAllCerts, SecureRandom())
            // Create an ssl socket factory with our all-trusting manager
            val sslSocketFactory = sslContext.socketFactory
            val okBuilder = OkHttpClient.Builder()
            okBuilder.sslSocketFactory(sslSocketFactory, trustAllCerts[0] as X509TrustManager)
            okBuilder.readTimeout(DEFAULT_TIMEOUT, TimeUnit.SECONDS)
            okBuilder.connectTimeout(DEFAULT_TIMEOUT, TimeUnit.SECONDS)
            okBuilder.writeTimeout(DEFAULT_TIMEOUT, TimeUnit.SECONDS)
            okBuilder.addInterceptor(if (BuildConfig.DEBUG) HttpLoggingInterceptor().setLevel(HttpLoggingInterceptor.Level.BODY) else HttpLoggingInterceptor().setLevel(HttpLoggingInterceptor.Level.NONE))
            /*okBuilder.addInterceptor { chain ->
                val request: Request = chain.request().newBuilder()
                                       .header("Cache-Control", "public") //如果只有一个请求头，就使用这
                                       .addHeader("header2","aa") //如果是多个请求头，就是用addHeader
                                       .removeHeader("Pragma")//删除掉请求过程中的所有key为Pragma的请求头
                                       .build()
                chain.proceed(request);
            }*/
            okBuilder.hostnameVerifier { _, _ -> true }
            okBuilder.build()
        } catch (e: Exception) {
            throw RuntimeException(e)
        }
    @SuppressLint("CustomX509TrustManager")
    private val trustAllCerts = arrayOf(object : X509TrustManager {
        @SuppressLint("TrustAllX509TrustManager")
        override fun checkClientTrusted(chain: Array, authType: String) {
        }

        @SuppressLint("TrustAllX509TrustManager")
        override fun checkServerTrusted(chain: Array, authType: String) {
        }

        override fun getAcceptedIssuers(): Array {
            return arrayOf()
        }
    })

}

4.http接口ApiService类

interface ApiService {

//ApiConfig为请求链接入（http://datavmap-public.oss-cn-hangzhou.aliyuncs.com/areas/csv/100000_province.json）

    @GET(ApiConfig.city) //get无参
    suspend fun getCity(): City

    @GET(SearchMusic)//get带参
    suspend fun getSearchMusic(
              @Query("keyword") keyword: String
    ): SearchList



  
   @POST(ApiConfig.user)//post无参
    suspend fun getUser(): User


    @POST(ApiConfig.Uid)//post带参
    suspend fun getUid(
        @Body uid: Uid
    ): UidData
}