目标

采用RxJava和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 'io.reactivex.rxjava2:rxjava:2.2.6'
implementation 'io.reactivex.rxjava2:rxandroid:2.1.1'
implementation 'com.squareup.retrofit2:adapter-rxjava2:2.6.2'

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")
    fun query(): Observable<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())
        .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
        .build()

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

5. activity调用

private fun queryData() {
    val networkService = getNetworkService()
    networkService.query()
        .subscribeOn(Schedulers.io())
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe { t -> contentTv.text = t.name }
}

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")
    fun query(): Observable<Task>

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

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

private fun queryData() {
    val networkService = getNetworkService()
    networkService.query()
        .subscribeOn(Schedulers.io())
        .observeOn(AndroidSchedulers.mainThread())
        .map { contentTv.text = it.name }
        .observeOn(Schedulers.io())
        .flatMap { return@flatMap networkService.query2() }
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe({ contentTv2.text = it.name },
            { Log.e("MainActivity2", it.message) }, {})
}

代码说明:
先调用query接口,然后再调用query2接口.

完整源代码

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