使用 Volley 在 kotlin 中创建请求类

Question

我正在尝试用 kotlin 创建一个通用的 Request 类，我可以用它来用 Volley 发出 Request。

我遇到的问题是我无法返回请求的响应。

我正在尝试获取请求的响应，以便处理数据。

我似乎找不到一个很好的资源来描述如何制作一个 Helper 类来发出请求

请求类

import android.content.Context
import android.util.Log
import com.android.volley.RequestQueue
import com.android.volley.Response
import com.android.volley.toolbox.StringRequest
import com.android.volley.toolbox.Volley

class Request(var context: Context, var url: String) {

    var response : String? = null

    fun makePOSTRequest() {

        val requestQueue: RequestQueue? = Volley.newRequestQueue(context)

        val stringRequest = object : StringRequest(
            Method.POST, url,
            Response.Listener { response ->

            }, Response.ErrorListener { error ->
                Log.i("Error", "[" + error + "]")
            }) {

            override fun getParams(): Map<String, String> {
                val params = HashMap<String, String>()
                return params
            }

        }

        requestQueue?.add(stringRequest)

    }

    fun makeGETRequest() {

        val requestQueue: RequestQueue? = Volley.newRequestQueue(context)

        val stringRequest = object : StringRequest(
            Method.GET, url,
            Response.Listener { response ->

                println(response) // Response: {"message":"ok","locaties"[{"id":"739","name":"Company","code":"","klant":"Client"}]}


               this.response = response // Here I'm trying to fill the response var



            }, Response.ErrorListener { error ->
                Log.i("Error", "[" + error + "]")
            }) {
        }

        requestQueue?.add(stringRequest)

    }


}

实施

var request = context?.let { Request(it, BuildConfig.API_URL + "getLocatiesLijst.php?name=" + bdl?.getString("name")) }

        request?.makeGETRequest()

        var response = request?.response

        println(response) // This give Null back

Answer 1

我一直忙于用协程实现一个请求助手类。我想我已经找到了解决我自己问题的方法。我正在使用协程使请求异步。

Source of solution

请求.kt

import android.content.Context
import com.android.volley.Request
import com.android.volley.Response
import com.android.volley.toolbox.StringRequest
import com.android.volley.toolbox.Volley
import kotlin.coroutines.*;

class Request(var context: Context, var url: String) {

    suspend fun makeGetRequest() = suspendCoroutine<String> { cont ->
        val queue = Volley.newRequestQueue(context)

        val stringRequest = StringRequest(
            Request.Method.GET, url,
            Response.Listener<String> { response ->
                cont.resume("Response is: ${response}")
            },
            Response.ErrorListener { cont.resume("Something went wrong!") })

        queue.add(stringRequest)
    }

}

实施

class LocationFragment : Fragment(), CoroutineScope {

     protected lateinit var job: Job
     override val coroutineContext: CoroutineContext
                get() = job + Dispatchers.Main

     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {

        var rootView =  inflater.inflate(R.layout.location_list, container, false)

        //TODO doe verzoek voor lijst van locaties

        val bdl = arguments

        var request = context?.let { Request(it, BuildConfig.API_URL + "getLocatiesLijst.php?name=" + bdl?.getString("name")) }

         job = Job()

         launch {
             val data = request?.makeGetRequest()
             println(data)
         }
    }

结果

I/System.out：响应为：{"message":"ok","locaties":[{"id":"739","name":"Company","lce_code":"code" ,"klant":"客户"}]}

Answer 2

我猜问题是请求是异步的，但是当你运行它时， println("") 将立即被调用。你应该等待结果。 您可以向监听器添加一些回调或尝试使用协程。