use new permission system and fix a few compiler warnings

app/src/main/java/info/nightscout/androidaps/activities/MyPreferenceFragment.kt

@@ -151,7 +151,7 @@ class MyPreferenceFragment : PreferenceFragmentCompat(), OnSharedPreferenceChang
     override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
         (savedInstanceState ?: arguments)?.let { bundle ->
             if (bundle.containsKey("id")) {
-                pluginId = bundle.getInt("id") ?: -1
+                pluginId = bundle.getInt("id")
             }
             if (bundle.containsKey("filter")) {
                 filter = bundle.getString("filter") ?: ""

app/src/main/java/info/nightscout/androidaps/plugins/general/maintenance/ImportExportPrefs.kt

@@ -1,13 +1,13 @@
 package info.nightscout.androidaps.plugins.general.maintenance
 
 import android.Manifest
-import androidx.appcompat.app.AppCompatActivity
 import android.bluetooth.BluetoothAdapter
 import android.content.Context
 import android.content.Intent
 import android.content.pm.PackageManager
 import android.provider.Settings
 import androidx.annotation.StringRes
+import androidx.appcompat.app.AppCompatActivity
 import androidx.core.content.ContextCompat
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.FragmentActivity
@@ -21,6 +21,7 @@ import info.nightscout.androidaps.logging.AAPSLogger
 import info.nightscout.androidaps.logging.LTag
 import info.nightscout.androidaps.plugins.bus.RxBusWrapper
 import info.nightscout.androidaps.plugins.general.maintenance.formats.*
+import info.nightscout.androidaps.utils.AndroidPermission
 import info.nightscout.androidaps.utils.DateUtil
 import info.nightscout.androidaps.utils.ToastUtils
 import info.nightscout.androidaps.utils.alertDialogs.OKDialog
@@ -43,12 +44,6 @@ import javax.inject.Singleton
  * Created by mike on 03.07.2016.
  */
 
-private const val REQUEST_EXTERNAL_STORAGE = 1
-private val PERMISSIONS_STORAGE = arrayOf(
-    Manifest.permission.READ_EXTERNAL_STORAGE,
-    Manifest.permission.WRITE_EXTERNAL_STORAGE
-)
-
 @Singleton
 class ImportExportPrefs @Inject constructor(
     private var log: AAPSLogger,
@@ -57,6 +52,7 @@ class ImportExportPrefs @Inject constructor(
     private val buildHelper: BuildHelper,
     private val rxBus: RxBusWrapper,
     private val passwordCheck: PasswordCheck,
+    private val androidPermission: AndroidPermission,
     private val classicPrefsFormat: ClassicPrefsFormat,
     private val encryptedPrefsFormat: EncryptedPrefsFormat,
     private val prefFileList: PrefFileListProvider
@@ -73,12 +69,15 @@ class ImportExportPrefs @Inject constructor(
     }
 
     fun verifyStoragePermissions(fragment: Fragment, onGranted: Runnable) {
-        fragment.context?.let {
+        fragment.context?.let { ctx ->
-            val permission = ContextCompat.checkSelfPermission(it,
+            val permission = ContextCompat.checkSelfPermission(ctx,
                 Manifest.permission.WRITE_EXTERNAL_STORAGE)
             if (permission != PackageManager.PERMISSION_GRANTED) {
                 // We don't have permission so prompt the user
-                fragment.requestPermissions(PERMISSIONS_STORAGE, REQUEST_EXTERNAL_STORAGE)
+                fragment.activity?.let {
+                    androidPermission.askForPermission(it, arrayOf(Manifest.permission.READ_EXTERNAL_STORAGE,
+                        Manifest.permission.WRITE_EXTERNAL_STORAGE), AndroidPermission.CASE_STORAGE)
+                }
             } else {
                 onGranted.run()
             }

app/src/main/java/info/nightscout/androidaps/utils/AndroidPermission.kt

@@ -46,7 +46,7 @@ class AndroidPermission @Inject constructor(
     private var permission_battery_optimization_failed = false
 
     @SuppressLint("BatteryLife")
-    private fun askForPermission(activity: FragmentActivity, permission: Array<String>, requestCode: Int) {
+    fun askForPermission(activity: FragmentActivity, permission: Array<String>, requestCode: Int) {
         var test = false
         var testBattery = false
         for (s in permission) {

omnipod/src/main/java/info/nightscout/androidaps/plugins/pump/omnipod/ui/PodManagementActivity.kt

@@ -209,7 +209,7 @@ class PodManagementActivity : NoSplashAppCompatActivity() {
     }
 
     private fun displayNotConfiguredDialog() {
-        context?.let {
+        context.let {
             UIRunnable(Runnable {
                 OKDialog.show(it, resourceHelper.gs(R.string.omnipod_warning),
                     resourceHelper.gs(R.string.omnipod_error_operation_not_possible_no_configuration), null)