目标

采用Coroutines结合Retrofit,发送单个或多个网络请求(串行),并更新UI.

实现方案

发送单个网络请求方案

1. 修改app工程的build.gradle文件

• 在android节点下添加如下信息

compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
}

• 添加依赖

implementation 'com.squareup.retrofit2:retrofit:2.7.2'
implementation 'com.squareup.retrofit2:converter-gson:2.7.2'

implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:1.3.3"
implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.3"

2. 定义数据类Task.kt

data class Task(val id: Int, var name: String)

3. 创建网络接口类NetworkService.kt

interface NetworkService {
    @GET("cxyzy1/AndroidAsyncTaskDemo/raw/master/data.json")
    suspend fun query(): Task
}

4. 创建网络工具类NetworkUtils.kt

fun getNetworkService(): NetworkService {
    val okHttpClient = OkHttpClient.Builder().build()
    val retrofit = Retrofit.Builder()
        .client(okHttpClient)
        .baseUrl("https://gitee.com/")
        .addConverterFactory(GsonConverterFactory.create())
        .build()

    return retrofit.create(NetworkService::class.java)
}

5. activity调用

private fun queryData() {
    val networkService = getNetworkService()
    GlobalScope.launch(Dispatchers.Main) {
        val result = withContext(Dispatchers.IO) { networkService.query() }
        contentTv.text = result.toString()
    }
}

发送两个网络请求方案

1. 修改app工程的build.gradle文件,同上
2. 定义数据类Task.kt,同上
3. 创建网络接口类NetworkService.kt

interface NetworkService {
    @GET("cxyzy1/AndroidAsyncTaskDemo/raw/master/data.json")
    suspend fun query(): Task

    @GET("cxyzy1/AndroidAsyncTaskDemo/raw/master/data2.json")
    suspend fun query2(): Task
}

4. 创建网络工具类NetworkUtils.kt,同上
5. activity调用

private fun queryData() {
    val networkService = getNetworkService()
    GlobalScope.launch(Dispatchers.Main) {
        val result = withContext(Dispatchers.IO) { networkService.query() }
        contentTv.text = result.name

        val result2 = withContext(Dispatchers.IO) { networkService.query2() }
        contentTv2.text = result2.name
    }
}

代码说明:
直接顺序调用query和query2两个接口.

完整源代码

https://gitee.com/cxyzy1/AndroidAsyncTaskDemo/tree/master/coroutinesDemo