make google sync service fetching a context extension function

app/src/main/kotlin/com/simplemobiletools/calendar/activities/SettingsActivity.kt

@@ -328,7 +328,7 @@ class SettingsActivity : SimpleActivity() {
             showAccountChooser()
         } else {
             credential.selectedAccountName = config.syncAccountName
-            FetchGoogleEventsTask(this, credential).execute()
+            FetchGoogleEventsTask(this).execute()
         }
     }
 

app/src/main/kotlin/com/simplemobiletools/calendar/asynctasks/FetchGoogleEventsTask.kt

@@ -4,17 +4,14 @@ import android.app.Activity
 import android.graphics.Color
 import android.os.AsyncTask
 import android.util.SparseIntArray
-import com.google.api.client.extensions.android.http.AndroidHttp
-import com.google.api.client.googleapis.extensions.android.gms.auth.GoogleAccountCredential
 import com.google.api.client.googleapis.extensions.android.gms.auth.UserRecoverableAuthIOException
-import com.google.api.client.json.gson.GsonFactory
 import com.google.gson.Gson
 import com.google.gson.JsonObject
 import com.google.gson.reflect.TypeToken
-import com.simplemobiletools.calendar.R
 import com.simplemobiletools.calendar.activities.SettingsActivity
 import com.simplemobiletools.calendar.extensions.config
 import com.simplemobiletools.calendar.extensions.dbHelper
+import com.simplemobiletools.calendar.extensions.getGoogleSyncService
 import com.simplemobiletools.calendar.extensions.seconds
 import com.simplemobiletools.calendar.helpers.*
 import com.simplemobiletools.calendar.models.*
@@ -22,7 +19,7 @@ import org.joda.time.DateTime
 import java.util.*
 
 // more info about event fields at https://developers.google.com/google-apps/calendar/v3/reference/events/insert
-class FetchGoogleEventsTask(val activity: Activity, credential: GoogleAccountCredential) : AsyncTask<Void, Void, List<Event>>() {
+class FetchGoogleEventsTask(val activity: Activity) : AsyncTask<Void, Void, List<Event>>() {
     private val CONFIRMED = "confirmed"
     private val PRIMARY = "primary"
     private val ITEMS = "items"
@@ -30,18 +27,11 @@ class FetchGoogleEventsTask(val activity: Activity, credential: GoogleAccountCre
     private val POPUP = "popup"
     private val NEXT_PAGE_TOKEN = "nextPageToken"
 
-    private var service: com.google.api.services.calendar.Calendar
     private var lastError: Exception? = null
     private var dbHelper = activity.dbHelper
     private var eventTypes = ArrayList<EventType>()
     private var eventColors = SparseIntArray()
-
+    private var service = activity.getGoogleSyncService()
-    init {
-        val transport = AndroidHttp.newCompatibleTransport()
-        service = com.google.api.services.calendar.Calendar.Builder(transport, GsonFactory(), credential)
-                .setApplicationName(activity.resources.getString(R.string.app_name))
-                .build()
-    }
 
     override fun doInBackground(vararg params: Void): List<Event>? {
         return try {

app/src/main/kotlin/com/simplemobiletools/calendar/extensions/Context.kt

@@ -13,6 +13,11 @@ import android.graphics.Color
 import android.net.Uri
 import android.os.Build
 import android.support.v7.app.NotificationCompat
+import com.google.api.client.extensions.android.http.AndroidHttp
+import com.google.api.client.googleapis.extensions.android.gms.auth.GoogleAccountCredential
+import com.google.api.client.json.gson.GsonFactory
+import com.google.api.client.util.ExponentialBackOff
+import com.google.api.services.calendar.CalendarScopes
 import com.simplemobiletools.calendar.R
 import com.simplemobiletools.calendar.activities.EventActivity
 import com.simplemobiletools.calendar.helpers.*
@@ -225,6 +230,15 @@ fun Context.launchNewEventIntent(startNewTask: Boolean = false, today: Boolean =
     }
 }
 
+fun Context.getGoogleSyncService(): com.google.api.services.calendar.Calendar {
+    val credential = GoogleAccountCredential.usingOAuth2(this, arrayListOf(CalendarScopes.CALENDAR)).setBackOff(ExponentialBackOff())
+    credential.selectedAccountName = config.syncAccountName
+    val transport = AndroidHttp.newCompatibleTransport()
+    return com.google.api.services.calendar.Calendar.Builder(transport, GsonFactory(), credential)
+            .setApplicationName(resources.getString(R.string.app_name))
+            .build()
+}
+
 fun Context.getNewEventTimestampFromCode(dayCode: String) = Formatter.getLocalDateTimeFromCode(dayCode).withTime(13, 0, 0, 0).seconds()
 
 fun Context.getCurrentOffset() = SimpleDateFormat("Z", Locale.getDefault()).format(Date())

app/src/main/kotlin/com/simplemobiletools/calendar/models/GoogleEvent.kt

@@ -3,5 +3,5 @@ package com.simplemobiletools.calendar.models
 import com.google.gson.JsonArray
 import com.google.gson.JsonObject
 
-data class GoogleEvent(val summary: String, val description: String, val status: String, val start: GoogleEventDateTime, val end: GoogleEventDateTime,
+data class GoogleEvent(val summary: String, val description: String?, val status: String, val start: GoogleEventDateTime, val end: GoogleEventDateTime,
                        val reminders: JsonObject, val recurrence: JsonArray?, val iCalUID: String, val colorId: Int, val updated: String)