Android Kotlin调用suspend函数getInfo报错，请求排查错误原因

错误信息：

suspend function 'getInfo' should be called only from a coroutine or another suspend function

WidgetService 类代码 #

import android.appwidget.AppWidgetManager
import android.content.BroadcastReceiver
import android.content.ComponentName
import android.content.Context
import android.content.Intent
import android.util.Log
import com.myapp.test.WakeLocker.acquire
import com.myapp.test.WakeLocker.release
import org.json.JSONObject
import java.util.concurrent.ExecutionException

class WidgetService : BroadcastReceiver() {
    var json = JSONObject()
    override fun onReceive(context: Context, intent: Intent) {
        //唤醒设备
        acquire(context)

        //更新widget中的数值
        val preferences = context.getSharedPreferences("PREFS", 0)
        val urlCode = preferences.getString("urlCode", "")
        Log.d("WidgetService1", urlCode!!)
        if (urlCode != "") {
            val getPack = GetPack(urlCode)
            json = try {
                getPack.getInfo()
            } catch (e: ExecutionException) {
                throw RuntimeException(e)
            } catch (e: InterruptedException) {
                throw RuntimeException(e)
            }
            val editor = preferences.edit()
            editor.putString("json", json.toString())
            editor.apply()
        }

        //强制更新widget
        val widgetIntent = Intent(context, MyWidget::class.java)
        widgetIntent.action = AppWidgetManager.ACTION_APPWIDGET_UPDATE
        val ids = AppWidgetManager.getInstance(context)
            .getAppWidgetIds(ComponentName(context, MyWidget::class.java))
        widgetIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_IDS, ids)
        context.sendBroadcast(widgetIntent)
        Log.d("WidgetService", "Widget set to update!")

        //释放唤醒锁
        release()
    }
}

GetPack 类代码 #

import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.withContext
import org.json.JSONArray
import org.json.JSONObject
import org.jsoup.Jsoup
import java.io.IOException

class GetPack(id: String) {
    private val baseURL = "http://192.xxx.xxx.xxx"
    private val finalURL = "$baseURL:8080"

    suspend fun getInfo(): JSONObject = withContext(Dispatchers.IO) {
        val json = JSONObject()
        try {
            val document = Jsoup.connect(finalURL).get()
            val steps = JSONArray()
            val elements = document.select("#progressTracker-container > div")
            for (ele in elements) {
                val item = JSONObject()
                val reached = ele.attr("data-reached") == "reached"
                val message = ele.select(".milestone-primaryMessage").first().ownText()
                val data = ele.select(".milestone-primaryMessage > .nowrap").text()
                item.put("reached", reached)
                item.put("message", message)
                item.put("data", data)
                steps.put(item)
            }
            val primaryStatus = document.getElementById("primaryStatus")
            json.put("status", primaryStatus.text())
            json.put("steps", steps)
        } catch (e: IOException) {
            e.printStackTrace()
        } catch (e: Exception) {
            throw RuntimeException(e)
        }
        json
    }
}

依赖配置 #

dependencies {

    implementation 'androidx.appcompat:appcompat:1.6.1'
    implementation 'com.google.android.material:material:1.5.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.1.4'
    testImplementation 'junit:junit:4.13.2'
    androidTestImplementation 'androidx.test.ext:junit:1.1.5'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.5.1'

    implementation 'org.jsoup:jsoup:1.11.2'
}

问题原因 #

getInfo()是标记为suspend的协程函数，这类函数的调用必须在协程作用域内，或者在另一个suspend函数中。但你直接在BroadcastReceiver的onReceive()（普通非suspend函数）里调用它，违反了协程的调用规则。另外你错误捕获了ExecutionException和InterruptedException——这两个是Java线程池相关异常，和Kotlin协程无关。

解决步骤 #

1. 添加协程依赖
   你的gradle配置中缺少Kotlin协程的Android依赖，先补充：

   implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.7.3'
   

2. 在onReceive中启动协程调用suspend函数
   使用自定义协程作用域在onReceive()内启动协程，处理耗时的网络请求。同时调整唤醒锁、widget更新的逻辑，确保异步任务完成后再执行收尾操作：

   import android.appwidget.AppWidgetManager
   import android.content.BroadcastReceiver
   import android.content.ComponentName
   import android.content.Context
   import android.content.Intent
   import android.util.Log
   import com.myapp.test.WakeLocker.acquire
   import com.myapp.test.WakeLocker.release
   import kotlinx.coroutines.CoroutineScope
   import kotlinx.coroutines.Dispatchers
   import kotlinx.coroutines.launch
   import org.json.JSONObject
   
   class WidgetService : BroadcastReceiver() {
       // 创建绑定IO调度器的协程作用域
       private val coroutineScope = CoroutineScope(Dispatchers.IO)
   
       override fun onReceive(context: Context, intent: Intent) {
           acquire(context)
   
           val preferences = context.getSharedPreferences("PREFS", 0)
           val urlCode = preferences.getString("urlCode", "") ?: ""
           Log.d("WidgetService1", urlCode)
           
           if (urlCode.isNotEmpty()) {
               coroutineScope.launch {
                   try {
                       val json = GetPack(urlCode).getInfo()
                       val editor = preferences.edit()
                       editor.putString("json", json.toString())
                       editor.apply()
                   } catch (e: Exception) {
                       Log.e("WidgetService", "获取数据失败", e)
                   } finally {
                       updateWidget(context)
                       release()
                   }
               }
           } else {
               updateWidget(context)
               release()
           }
       }
   
       private fun updateWidget(context: Context) {
           val widgetIntent = Intent(context, MyWidget::class.java)
           widgetIntent.action = AppWidgetManager.ACTION_APPWIDGET_UPDATE
           val ids = AppWidgetManager.getInstance(context)
               .getAppWidgetIds(ComponentName(context, MyWidget::class.java))
           widgetIntent.putExtra(AppWidgetManager.EXTRA_APPWIDGET_IDS, ids)
           context.sendBroadcast(widgetIntent)
           Log.d("WidgetService", "Widget set to update!")
       }
   }
   

3. 优化GetPack的异常处理
   可以将返回值改为可空类型，避免未处理的异常导致崩溃：

   suspend fun getInfo(): JSONObject? = withContext(Dispatchers.IO) {
       val json = JSONObject()
       return@withContext try {
           val document = Jsoup.connect(finalURL).get()
           val steps = JSONArray()
           val elements = document.select("#progressTracker-container > div")
           for (ele in elements) {
               val item = JSONObject()
               val reached = ele.attr("data-reached") == "reached"
               val message = ele.select(".milestone-primaryMessage").first()?.ownText() ?: ""
               val data = ele.select(".milestone-primaryMessage > .nowrap").text()
               item.put("reached", reached)
               item.put("message", message)
               item.put("data", data)
               steps.put(item)
           }
           val primaryStatus = document.getElementById("primaryStatus")
           json.put("status", primaryStatus?.text() ?: "")
           json.put("steps", steps)
           json
       } catch (e: IOException) {
           e.printStackTrace()
           null
       } catch (e: Exception) {
           Log.e("GetPack", "解析失败", e)
           null
       }
   }
   

内容的提问来源于stack exchange，提问作者Paul