fix exception on hostname detection

Author: lhns

app/src/main/AndroidManifest.xml

@@ -2,8 +2,8 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
 
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+    <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
     <uses-permission android:name="android.permission.INTERNET" />
-    <uses-permission android:name="android.permission.BLUETOOTH" />
     <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
     <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

app/src/main/java/de/lolhens/resticui/BackupManager.kt

@@ -57,16 +57,16 @@ class BackupManager private constructor(context: Context) {
                 ResticNameServers.fromContext(context)
         _restic = Restic(
             ResticStorage.fromContext(context),
-            hostname = config.hostname ?: HostnameUtil.detectHostname(),
+            hostname = config.hostname ?: HostnameUtil.detectHostname(context),
             nameServers = resticNameServers
         )
     }
 
-    fun setHostname(hostname: String?): String {
+    fun setHostname(hostname: String?, defaultHostname: () -> String): String {
         configure { config ->
             config.copy(hostname = hostname)
         }
-        val hostname = hostname ?: HostnameUtil.detectHostname()
+        val hostname = hostname ?: defaultHostname()
         _restic = _restic.withHostname(hostname)
         return hostname
     }

app/src/main/java/de/lolhens/resticui/ui/settings/SettingsFragment.kt

@@ -8,6 +8,7 @@ import androidx.fragment.app.Fragment
 import de.lolhens.resticui.BackupManager
 import de.lolhens.resticui.databinding.FragmentSettingsBinding
 import de.lolhens.resticui.ui.InputDialogUtil
+import de.lolhens.resticui.util.HostnameUtil
 
 class SettingsFragment : Fragment() {
     private var _binding: FragmentSettingsBinding? = null
@@ -66,7 +67,9 @@ class SettingsFragment : Fragment() {
                 binding.textHostname.text = BackupManager.instance(requireContext()).setHostname(
                     if (hostname.isBlank()) null
                     else hostname.trim()
-                )
+                ) {
+                    HostnameUtil.detectHostname(requireContext())
+                }
             }
         }
 

app/src/main/java/de/lolhens/resticui/util/HostnameUtil.kt

@@ -1,17 +1,26 @@
 package de.lolhens.resticui.util
 
+import android.Manifest
 import android.bluetooth.BluetoothAdapter
+import android.content.Context
+import android.content.pm.PackageManager
+import androidx.core.app.ActivityCompat
 
 object HostnameUtil {
     private const val DEFAULT_HOSTNAME = "android-device"
 
-    fun detectHostname(): String {
-        val blueToothAdapter = BluetoothAdapter.getDefaultAdapter()
+    fun detectHostname(context: Context): String {
+        if (ActivityCompat.checkSelfPermission(
+                context,
+                Manifest.permission.BLUETOOTH_CONNECT
+            ) == PackageManager.PERMISSION_GRANTED
+        ) {
+            val bluetoothAdapter = BluetoothAdapter.getDefaultAdapter()
 
-        if (blueToothAdapter != null) {
-            // Some Devices do not have a BluetoothAdapter e.g. the Android Emulator. For this case we use a default
-            // value
-            return BluetoothAdapter.getDefaultAdapter().name
+            // Some Devices do not have a BluetoothAdapter e.g. the Android Emulator
+            if (bluetoothAdapter != null) {
+                return bluetoothAdapter.name
+            }
         }
 
         return DEFAULT_HOSTNAME