如何检查异步任务是否从另一个类中完成

Question

我有一个片段，它运行asynctask来通过解析api并将其存储在数组列表中来获取数据。

但是我想做的是我想从另一个类中打印该列表，以便我可以创建搜索过滤器。

package com.example.rsquare_android_fixed.mywork.building

import android.os.AsyncTask
import android.os.Bundle
import android.util.Log
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import androidx.core.view.size
import androidx.fragment.app.Fragment
import com.example.rsquare_android_fixed.R
import com.example.test.mainF.Address_data
import kotlinx.android.synthetic.main.fragment_building.*
import org.json.JSONArray
import org.json.JSONObject
import java.net.HttpURLConnection
import java.net.URL

class buildingFragment: Fragment(){

    private val list=ArrayList<Address_data>()
    private val list2=ArrayList<Address_map>()
    public var list3=ArrayList<Address_all>()
    public var check_list3:Int = 0


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


        val inflate=inflater.inflate(R.layout.fragment_building, container, false)

        val url="https://manage-dev.rsquare.co.kr/api/sample/buildings"

        AsyncTaskHandleJson().execute(url)
        return inflate
    }

    inner class AsyncTaskHandleJson: AsyncTask<String, String, String>(){
        override fun doInBackground(vararg url: String?): String {
            var text:String
            val connection= URL(url[0]).openConnection() as HttpURLConnection

            try{
                connection.connect()
                text=connection.inputStream.use{it.reader().use{reader->reader.readText()}}
            }
            finally{
                connection.disconnect()
            }

            return text
        }

        override fun onPostExecute(result: String?) {
            super.onPostExecute(result)
            handleJson(result)

            naverGeo()
        }

        //json parsing
        private fun handleJson(jsonString: String?) {
            val jsonArray= JSONArray(jsonString)
            //val list=ArrayList<Address_data>()
            var x=0
            while(x<jsonArray.length()){
                val jsonObject=jsonArray.getJSONObject(x)
                list.add(
                    Address_data(
                        jsonObject.getString("address"),
                        jsonObject.getString("bunji"),
                        jsonObject.getString("streetAddress"),
                        jsonObject.getString("updateAt")
                    )
                )
                x++
            }
            val adapter=MW_Adapter_list(requireActivity(),list)
            data_list.adapter=adapter

//            val a = list[0]
//            a.address
            list.forEach { println(it) }
            println("listsize1="+list.size)

        }
    }

    
    fun naverGeo(){
        println("naverGeo")
        var query:String
        println("listsize2="+list.size)
        for(i in 0..list.size-1){
            var a = list[i]
            query=a.address

            println("test  : $i")
            println("query : $query")
            var url2 = "https://naveropenapi.apigw.ntruss.com/map-geocode/v2/geocode?X-NCP-APIGW-API-KEY-ID=key&X-NCP-APIGW-API-KEY=pw&query="+query

            AsyncTaskNaver().execute(url2)
        }
    }

    inner class AsyncTaskNaver:AsyncTask<String,String,String>(){
        override fun doInBackground(vararg url2: String?): String {
            var text:String
            val connection=URL(url2[0]).openConnection() as HttpURLConnection

            try{
                connection.connect()
                text=connection.inputStream.use{it.reader().use{reader->reader.readText()}}
            }
            finally{
                connection.disconnect()
            }
            return text
        }

        override fun onPostExecute(result: String?) {
            super.onPostExecute(result)
            handleJson2(result)

            //merge to longitude and latitude with original data
            if(list2.size==30){
                mergeList()
            }
        }
        private fun handleJson2(jsonString: String?){
            val jsonObj=JSONObject(jsonString)
            val jsonArray=JSONArray(jsonObj.get("addresses").toString())
            var x=0
            while(x<jsonArray.length()){
                val jsonObject=jsonArray.getJSONObject(x)
                list2.add(
                    Address_map(
                        jsonObject.getString("roadAddress"),
                        jsonObject.getString("x"), //long
                        jsonObject.getString("y") //lat
                    )
                )
                x++
            }
            //println(list2.size)
        }
    }


    fun mergeList(){
        //println(list2.size)
        for (i in 0..list.size-1){
            var list_api=list[i]
            var list_naver=list2[i]
            var query_api=list_api.address
            var query_naver=list_naver.raddress
            var bunji_api=list_api.bunji
            var street_api=list_api.streeetAddress
            var long_naver=list_naver.x
            var lat_naver=list_naver.y

            //by comparing first 2 letters, last 3 letters from address to merge them into one
            if(query_api.takeLast(3)==query_naver.takeLast(3)&&query_api.take(2)==query_naver.take(2)){
                list3.add(
                    Address_all(
                        query_api,
                        bunji_api,
                        street_api,
                        long_naver,
                        lat_naver
                    )
                )
            }

        }
        check_list3=1
        list3.forEach { println(it) }

    }

}

以下是我要在其中打印列表的另一个代码

package com.example.rsquare_android_fixed.mywork.search

import android.os.Bundle
import android.text.Editable
import android.text.TextWatcher
import android.util.Log
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.view.inputmethod.EditorInfo
import android.widget.ListView
import android.widget.TextView
import androidx.appcompat.widget.SearchView
import androidx.fragment.app.Fragment
import com.example.rsquare_android_fixed.R
import com.example.rsquare_android_fixed.mywork.building.MWFragment
import com.example.rsquare_android_fixed.mywork.building.MW_Adapter_list
import com.example.rsquare_android_fixed.mywork.building.buildingFragment
import com.naver.maps.geometry.LatLng
import com.naver.maps.geometry.LatLngBounds
import com.naver.maps.map.NaverMap
import com.naver.maps.map.NaverMapSdk
import com.naver.maps.map.overlay.Marker
import kotlinx.android.synthetic.main.fragment_building.*
import kotlinx.android.synthetic.main.fragment_search.*
import kotlinx.android.synthetic.main.list_search.*


class searchFragment: Fragment(){

    private var list: ListView?=null
    private var adapter:SearchAdapter?=null
    private var editsearch:SearchView?=null
    private var addrList:Array<String>?=null
    //lateinit var naverMap:NaverMap

    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
        val view:View = inflater.inflate(R.layout.fragment_search, container, false)

        //list=findViewById(R.id.search_list) as ListView

        val a = buildingFragment()
        if(a.check_list3==0){
            println("nulnunlnlunlnl")
        }
        else{
            println(a.list3)
            println("not null")
            //println(a.list3)
        }
        return view
    }

    /*override fun onViewCreated(view: View, savedInstanceState: Bundle?) {

        super.onViewCreated(view, savedInstanceState)

        //NaverMapSdk.getInstance(requireContext()).client=NaverMapSdk.NaverCloudPlatformClient("dp3mci4foz")

        val a = buildingFragment()

    }

     */

}

我认为我的第二个代码正在调用列表中的代码，然后从第一个代码完成asynctask。这导致我打印空列表。

所以第二代码有什么方法可以注意到第一代码已完成asynctask？

（很抱歉，我的代码很脏）

Answer 1

创建界面

interface CallBack {
    fun asyncompleted(list:ArrayList<Address_all>)
}

在searchFragment中实现。

class searchFragment: Fragment(), CallBack {
    fun asyncCompleted(list:ArrayList<Address_all>) {
      println(list)
   }
}

在buildingFragment中创建方法

var callback: CallBack 
setCallback(value) { callback = value }  

在searchFragment中创建buildingFragment实例后设置回调

val a = buildingFragment()
a.setCallback(this)

设置列表3后调用异步完成的方法

override fun onPostExecute(result: String?) {
        super.onPostExecute(result)
        handleJson2(result)

        //merge to longitude and latitude with original data
        if(list2.size==30){
            mergeList()
        }
        callback.asyncompleted(list3)
 }