Add option to start directly into web gui (fixes #578)

src/main/java/com/nutomic/syncthingandroid/activities/FirstStartActivity.java

@@ -60,11 +60,18 @@ public class FirstStartActivity extends Activity implements Button.OnClickListen
         if (isFirstStart) {
             mPreferences.edit().putBoolean("first_start", false).apply();
         }
-        Intent intent = new Intent(this, MainActivity.class);
-        intent.putExtra(MainActivity.EXTRA_FIRST_START, isFirstStart);
-        startActivity(intent);
-        finish();
 
+        // In case start_into_web_gui option is enabled, start both activities so that back
+        // navigation works as expected.
+        Intent mainIntent = new Intent(this, MainActivity.class);
+        mainIntent.putExtra(MainActivity.EXTRA_FIRST_START, isFirstStart);
+        Intent webIntent = new Intent(this, WebGuiActivity.class);
+        if (mPreferences.getBoolean("start_into_web_gui", false)) {
+            startActivities(new Intent[] {mainIntent, webIntent});
+        } else {
+            startActivity(mainIntent);
+        }
+        finish();
     }
 
     private boolean haveStoragePermission() {

src/main/res/values/strings.xml

@@ -277,6 +277,10 @@ Please report any problems you encounter via Github.</string>
 
     <string name="preference_language_summary">Change the app language</string>
 
+    <string name="start_into_web_gui_title">Start directly into web GUI</string>
+
+    <string name="start_into_web_gui_summary">When starting the app, open web GUI instead of the main screen</string>
+
     <string name="pref_language_default">Default Language</string>
 
     <string-array name="versioning_types">

src/main/res/xml/app_settings.xml

@@ -54,6 +54,12 @@
             android:title="@string/preference_language_title"
             android:summary="@string/preference_language_summary" />
 
+        <CheckBoxPreference
+            android:key="start_into_web_gui"
+            android:title="@string/start_into_web_gui_title"
+            android:summary="@string/start_into_web_gui_summary"
+            android:defaultValue="false"/>
+
     </PreferenceScreen>
 
     <PreferenceScreen