Handle API changes

mobile/src/main/java/be/mygod/vpnhotspot/App.kt

@@ -7,13 +7,13 @@ import android.content.res.Configuration
 import android.net.ConnectivityManager
 import android.net.wifi.WifiManager
 import android.os.Build
-import android.preference.PreferenceManager
 import androidx.browser.customtabs.CustomTabsIntent
 import androidx.core.content.ContextCompat
 import androidx.core.content.getSystemService
 import androidx.core.provider.FontRequest
 import androidx.emoji.text.EmojiCompat
 import androidx.emoji.text.FontRequestEmojiCompatConfig
+import androidx.preference.PreferenceManager
 import be.mygod.vpnhotspot.net.DhcpWorkaround
 import be.mygod.vpnhotspot.room.AppDatabase
 import be.mygod.vpnhotspot.util.DeviceStorageApp
@@ -32,7 +32,8 @@ class App : Application() {
         app = this
         if (Build.VERSION.SDK_INT >= 24) {
             deviceStorage = DeviceStorageApp(this)
-            deviceStorage.moveSharedPreferencesFrom(this, PreferenceManager.getDefaultSharedPreferencesName(this))
+            // alternative to PreferenceManager.getDefaultSharedPreferencesName(this)
+            deviceStorage.moveSharedPreferencesFrom(this, PreferenceManager(this).sharedPreferencesName)
             deviceStorage.moveDatabaseFrom(this, AppDatabase.DB_NAME)
         } else deviceStorage = this
         DebugHelper.init()
@@ -51,7 +52,7 @@ class App : Application() {
         if (DhcpWorkaround.shouldEnable) DhcpWorkaround.enable(true)
     }
 
-    override fun onConfigurationChanged(newConfig: Configuration?) {
+    override fun onConfigurationChanged(newConfig: Configuration) {
         super.onConfigurationChanged(newConfig)
         ServiceNotification.updateNotificationChannels()
     }

mobile/src/main/java/be/mygod/vpnhotspot/RepeaterService.kt

@@ -120,9 +120,9 @@ class RepeaterService : Service(), WifiP2pManager.ChannelListener, SharedPrefere
                 if (intent.getIntExtra(WifiP2pManager.EXTRA_WIFI_STATE, 0) ==
                         WifiP2pManager.WIFI_P2P_STATE_DISABLED) clean() // ignore P2P enabled
             WifiP2pManager.WIFI_P2P_CONNECTION_CHANGED_ACTION -> onP2pConnectionChanged(
-                    intent.getParcelableExtra(WifiP2pManager.EXTRA_WIFI_P2P_INFO),
+                    intent.getParcelableExtra(WifiP2pManager.EXTRA_WIFI_P2P_INFO)!!,
                     intent.getParcelableExtra(WifiP2pManager.EXTRA_NETWORK_INFO),
-                    intent.getParcelableExtra(WifiP2pManager.EXTRA_WIFI_P2P_GROUP))
+                    intent.getParcelableExtra(WifiP2pManager.EXTRA_WIFI_P2P_GROUP)!!)
         }
     }
     private val deviceListener = broadcastReceiver { _, intent ->

mobile/src/main/java/be/mygod/vpnhotspot/TetheringService.kt

@@ -90,7 +90,7 @@ class TetheringService : IpNeighbourMonitoringService() {
                     if (start()) check(downstreams.put(iface, this) == null) else destroy()
                 }
             }
-            intent.getStringExtra(EXTRA_ADD_INTERFACE_MONITOR)?.let { iface ->
+            intent.getStringExtra(EXTRA_ADD_INTERFACE_MONITOR)?.also { iface ->
                 val downstream = downstreams[iface]
                 if (downstream == null) Downstream(this, iface, true).apply {
                     start()
@@ -98,7 +98,7 @@ class TetheringService : IpNeighbourMonitoringService() {
                     downstreams[iface] = this
                 } else downstream.monitor = true
             }
-            downstreams.remove(intent.getStringExtra(EXTRA_REMOVE_INTERFACE))?.destroy()
+            intent.getStringExtra(EXTRA_REMOVE_INTERFACE)?.also { downstreams.remove(it)?.destroy() }
             updateNotification()    // call this first just in case we are shutting down immediately
             onDownstreamsChangedLocked()
         } else if (downstreams.isEmpty()) stopSelf(startId)

mobile/src/main/java/be/mygod/vpnhotspot/client/MacLookup.kt

@@ -47,7 +47,7 @@ object MacLookup {
             try {
                 val response = conn.inputStream.bufferedReader().readText()
                 val obj = JSONObject(response).getJSONObject("result")
-                obj.optString("error", null)?.also { throw UnexpectedError(mac, it) }
+                obj.opt("error")?.also { throw UnexpectedError(mac, it.toString()) }
                 val company = obj.getString("company")
                 val match = extractCountry(mac, response, obj)
                 val result = if (match != null) {
@@ -71,7 +71,7 @@ object MacLookup {
     }
 
     private fun extractCountry(mac: Long, response: String, obj: JSONObject): MatchResult? {
-        obj.optString("country")?.let { countryCodeRegex.matchEntire(it) }?.also { return it }
+        countryCodeRegex.matchEntire(obj.optString("country"))?.also { return it }
         val address = obj.optString("address")
         if (address.isNullOrBlank()) return null
         countryCodeRegex.find(address)?.also { return it }

mobile/src/main/java/be/mygod/vpnhotspot/net/wifi/WifiApManager.kt

@@ -25,11 +25,13 @@ object WifiApManager {
     private fun WifiManager.setWifiApEnabled(wifiConfig: WifiConfiguration?, enabled: Boolean) =
             setWifiApEnabled.invoke(this, wifiConfig, enabled) as Boolean
 
+    @Suppress("DEPRECATION")
     @Deprecated("Not usable since API 26, malfunctioning on API 25")
     fun start(wifiConfig: WifiConfiguration? = null) {
         app.wifi.isWifiEnabled = false
         app.wifi.setWifiApEnabled(wifiConfig, true)
     }
+    @Suppress("DEPRECATION")
     @Deprecated("Not usable since API 26")
     fun stop() {
         app.wifi.setWifiApEnabled(null, false)

mobile/src/main/java/be/mygod/vpnhotspot/util/SpanFormatter.kt

@@ -57,7 +57,7 @@ object SpanFormatter {
             i = m.start()
             val exprEnd = m.end()
 
-            val argTerm = m.group(1)
+            val argTerm = m.group(1)!!
             val modTerm = m.group(2)
             val typeTerm = m.group(3)