Fixed Bluetooth scan not working on Android 6.0

android/src/main/AndroidManifest.xml

@@ -9,6 +9,7 @@
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
     <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
+    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
 
     <uses-feature android:name="android.hardware.bluetooth" android:required="false" />
 

android/src/main/res/values/strings.xml

@@ -18,6 +18,8 @@
     <!-- Label for button to finish activity -->
     <string name="done">Done</string>
 
+    <!-- Toast shown if location permission is not granted -->
+    <string name="toast_location_required">Location permission is required to scan for other Bluetooth devices</string>
 
     <!-- MainActivity -->
 

android/src/main/scala/com/nutomic/ensichat/activities/FirstStartActivity.scala

@@ -1,15 +1,19 @@
 package com.nutomic.ensichat.activities
 
+import android.Manifest
 import android.bluetooth.BluetoothAdapter
+import android.content.pm.PackageManager
 import android.content.{Context, Intent}
 import android.os.Bundle
 import android.preference.PreferenceManager
+import android.support.v4.app.ActivityCompat
+import android.support.v4.content.ContextCompat
 import android.support.v7.app.AppCompatActivity
 import android.view.View.OnClickListener
 import android.view.inputmethod.{EditorInfo, InputMethodManager}
 import android.view.{KeyEvent, View}
 import android.widget.TextView.OnEditorActionListener
-import android.widget.{Button, EditText, TextView}
+import android.widget.{Button, EditText, TextView, Toast}
 import com.nutomic.ensichat.R
 import com.nutomic.ensichat.core.interfaces.SettingsInterface
 import com.nutomic.ensichat.core.interfaces.SettingsInterface._
@@ -20,6 +24,7 @@ import com.nutomic.ensichat.core.interfaces.SettingsInterface._
 class FirstStartActivity extends AppCompatActivity with OnEditorActionListener with OnClickListener {
 
   private val KeyIsFirstStart = "first_start"
+  private val RequestLocationPermission = 127
 
   private lazy val preferences = PreferenceManager.getDefaultSharedPreferences(this)
   private lazy val imm = getSystemService(Context.INPUT_METHOD_SERVICE)
@@ -31,11 +36,6 @@ class FirstStartActivity extends AppCompatActivity with OnEditorActionListener w
   override def onCreate(savedInstanceState: Bundle): Unit = {
     super.onCreate(savedInstanceState)
 
-    if (!preferences.getBoolean(KeyIsFirstStart, true)) {
-      startMainActivity()
-      return
-    }
-
     setContentView(R.layout.activity_first_start)
     setTitle(R.string.welcome)
 
@@ -43,7 +43,16 @@ class FirstStartActivity extends AppCompatActivity with OnEditorActionListener w
     username.setOnEditorActionListener(this)
     done.setOnClickListener(this)
 
-    imm.showSoftInput(username, InputMethodManager.SHOW_IMPLICIT)
+    val permission = ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION)
+    if (preferences.getBoolean(KeyIsFirstStart, true)) {
+      imm.showSoftInput(username, InputMethodManager.SHOW_IMPLICIT)
+    }
+    else if (permission != PackageManager.PERMISSION_GRANTED) {
+      requestLocationPermission()
+    }
+    else {
+      startMainActivity()
+    }
   }
 
   /**
@@ -77,7 +86,20 @@ class FirstStartActivity extends AppCompatActivity with OnEditorActionListener w
       .putString(KeyAddresses,              DefaultAddresses)
       .apply()
 
-    startMainActivity()
+    requestLocationPermission()
+  }
+
+  private def requestLocationPermission(): Unit =
+    ActivityCompat.requestPermissions(this, Array(Manifest.permission.ACCESS_COARSE_LOCATION), RequestLocationPermission)
+
+  override def onRequestPermissionsResult(requestCode: Int,
+                                          permissions: Array[String], grantResults: Array[Int]): Unit = requestCode match {
+    case RequestLocationPermission =>
+      if (grantResults.length > 0 && grantResults(0) == PackageManager.PERMISSION_GRANTED) {
+        startMainActivity()
+      } else {
+        Toast.makeText(this, R.string.toast_location_required, Toast.LENGTH_SHORT).show()
+      }
   }
 
   def startMainActivity(): Unit = {