Back up string set preferences

app/src/main/java/org/tasks/backup/BackupContainer.kt

@@ -17,8 +17,9 @@ class BackupContainer(
         val intPrefs: Map<String, Integer>?,
         val longPrefs: Map<String, java.lang.Long>?,
         val stringPrefs: Map<String, String>?,
-        val boolPrefs: Map<String, java.lang.Boolean>?) {
-
+        val boolPrefs: Map<String, java.lang.Boolean>?,
+        val setPrefs: Map<String, java.util.Set<*>>?,
+) {
     class TaskBackup(
             val task: Task,
             val alarms: List<Alarm>,

app/src/main/java/org/tasks/backup/TasksJsonExporter.kt

@@ -135,7 +135,9 @@ class TasksJsonExporter @Inject constructor(
                 preferences.getPrefs(Integer::class.java),
                 preferences.getPrefs(java.lang.Long::class.java),
                 preferences.getPrefs(String::class.java),
-                preferences.getPrefs(java.lang.Boolean::class.java))
+                preferences.getPrefs(java.lang.Boolean::class.java),
+                preferences.getPrefs(java.util.Set::class.java),
+        )
         val out = OutputStreamWriter(os, UTF_8)
         val gson = if (BuildConfig.DEBUG) GsonBuilder().setPrettyPrinting().create() else Gson()
         out.write(gson.toJson(data))

app/src/main/java/org/tasks/backup/TasksJsonImporter.kt

@@ -207,6 +207,10 @@ class TasksJsonImporter @Inject constructor(
                     .boolPrefs
                     ?.filterNot { (key, _) -> ignoreKeys.contains(key) }
                     ?.forEach { (key, value) -> preferences.setBoolean(key, value as Boolean) }
+            backupContainer
+                    .setPrefs
+                    ?.filterNot { (key, _) -> ignoreKeys.contains(key) }
+                    ?.forEach { (key, value) -> preferences.setStringSet(key, value as HashSet<String>)}
             if (version < Upgrader.V8_2) {
                 val themeIndex = preferences.getInt(R.string.p_theme_color, 7)
                 preferences.setInt(

app/src/main/java/org/tasks/preferences/Preferences.kt

@@ -243,10 +243,10 @@ class Preferences @JvmOverloads constructor(
         editor.apply()
     }
 
-    fun setStringSet(key: Int, newValue: HashSet<String>) =
+    fun setStringSet(key: Int, newValue: Set<String>) =
         setStringSet(context.getString(key), newValue)
 
-    private fun setStringSet(key: String, newValue: HashSet<String>) {
+    fun setStringSet(key: String, newValue: Set<String>) {
         val editor = prefs.edit()
         editor.putStringSet(key, newValue)
         editor.apply()