java - 改造中的多个相似请求顺序

Question

Retrofit中有没有什么方法可以顺序执行多个请求？

这些请求使用相同的 Java 接口(interface)，只是它们采用的参数不同，这些参数包含在 ArrayList 中。

对于请求A1、A2、A3、A4、A5……一个

1. 点击A1，

2. A1的onResponse()被调用

3. 点击A2，

4. A2的onResponse()被调用

5. 点击 A3.

.

.

.

.

.调用 An 的 onResponse()。

Answer 1

这个问题可以用RxJava轻松解决.

假设您有一个 retrofit Api 类，它返回一个 Completable :

    interface Api {
      @GET(...)
      fun getUser(id: String): Completable
    }

然后你可以执行这个:

    // Create a stream, that emits each item from the list, in this case "param1" continued with "param2" and then "param3"
    Observable.fromIterable(listOf("param1", "param2", "param3"))
      // we are converting `Observable` stream into `Completable`
      // also we perform request here: first time parameter `it` is equal to "param1", so a request is being made with "param1"
      // execution will halt here until responce is received. If response is successful, only then a call with second param ("param2") will be executed
      // then the same again with "param3"
      .flatMapCompletable { api.getUser(it) }
      // we want request to happen on a background thread
      .subscribeOn(Schedulers.io())
      // we want to be notified about completition on UI thread
      .observeOn(AndroidSchedulers.mainThread())
      // here we'll get notified, that operation has either successfully performed OR failed for some reason (specified by `Throwable it`)
      .subscribe({ println("completed") }, { println(it.message) })

如果您的改造 API 未返回 Completable，则将 api.getUser(it) 更改为 api.getUser(it).toCompletable().