Added option to start on boot (fixes #19).

This does not trigger the "enable Bluetooth" dialog, which means
Bluetooth won't be enabled. Even if Bluetooth was already active,
we might not have the necessary permissions. Internet will work
fine though.

android/src/main/AndroidManifest.xml

@@ -6,6 +6,7 @@
 
     <uses-permission android:name="android.permission.BLUETOOTH" />
     <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
+    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
 
     <uses-feature android:name="android.hardware.bluetooth" android:required="true" />
 
@@ -51,6 +52,12 @@
                 android:value=".activities.MainActivity" />
         </activity>
 
+        <receiver android:name=".service.BootReceiver">
+            <intent-filter>
+                <action android:name="android.intent.action.BOOT_COMPLETED"/>
+            </intent-filter>
+        </receiver>
+
         <service android:name=".service.ChatService" />
 
     </application>

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

@@ -78,6 +78,9 @@
     <!-- Preference title -->
     <string name="scan_interval_seconds">Scan Interval (seconds)</string>
 
+    <!-- Preference title -->
+    <string name="start_on_boot">Start on Boot</string>
+
     <!-- Preference title -->
     <string name="notification_sounds">Notification Sounds</string>
 

android/src/main/res/xml/settings.xml

@@ -12,6 +12,10 @@
         android:key="user_status"
         android:inputType="textCapSentences" />
 
+    <CheckBoxPreference
+        android:title="@string/start_on_boot"
+        android:key="start_on_boot" />
+
     <CheckBoxPreference
         android:title="@string/notification_sounds"
         android:key="notification_sounds" />

android/src/main/scala/com/nutomic/ensichat/service/BootReceiver.scala

@@ -0,0 +1,18 @@
+package com.nutomic.ensichat.service
+
+import android.content.{Intent, Context, BroadcastReceiver}
+import android.preference.PreferenceManager
+
+/**
+ * Starts [[ChatService]] on boot if preference is enabled.
+ */
+class BootReceiver extends BroadcastReceiver {
+
+  override def onReceive(context: Context, intent: Intent): Unit = {
+    val sp = PreferenceManager.getDefaultSharedPreferences(context)
+    if (sp.getBoolean("start_on_boot", false)) {
+      context.startService(new Intent(context, classOf[ChatService]))
+    }
+  }
+
+}