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

Question

I am getting the following error:

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

Can you tell me what I'm doing wrong?

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) {
        //wake the device
        acquire(context)

        //increase the number in the widget
        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()
        }

        //force widget update
        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!")

        //go back to sleep
        release()
    }
}

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
    }
}

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'
}

Answer 1

Your suspend fun getInfo() from GetPack class is mentioned with suspend. In Kotlin, suspend functions should be either called from suspend function or from Coroutines.

More regarding Coroutines: https://developer.android.com/kotlin/coroutines/coroutines-adv

Answer:

You can either do one of the following to resolve this error:

1. Remove suspend from getInfo() and make it simple fun getInfo(). But my suggestion is don't do this as we are doing Json parsing here which might take time.
2. Instead, in the WidgetService class you can start Coroutine with IO dispatcher as follow:

1. Add implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.4.0' in app build gradle. 
2. Use lifecycleScope.launch(Dispatchers.IO) {} as follow

        lifecycleScope.launch(Dispatchers.IO) {
            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()
        }