Bugfix: [Android] Joystick is not visible if connected after start of QGC

When starting up, if you start the GS before connecting the bluetooth joystick the QGC needs to be closed and restarted to get it to recognize the joystick

src/Joystick/JoystickAndroid.cc

@@ -73,7 +73,6 @@ JoystickAndroid::~JoystickAndroid() {
 
 
 QMap<QString, Joystick*> JoystickAndroid::discover(MultiVehicleManager* _multiVehicleManager) {
-    bool joystickFound = false;
     static QMap<QString, Joystick*> ret;
 
     QMutexLocker lock(&m_mutex);
@@ -87,6 +86,8 @@ QMap<QString, Joystick*> JoystickAndroid::discover(MultiVehicleManager* _multiVe
     int SOURCE_GAMEPAD = QAndroidJniObject::getStaticField<jint>("android/view/InputDevice", "SOURCE_GAMEPAD");
     int SOURCE_JOYSTICK = QAndroidJniObject::getStaticField<jint>("android/view/InputDevice", "SOURCE_JOYSTICK");
 
+    QList<QString> names;
+
     for (int i = 0; i < sz; ++i) {
         QAndroidJniObject inputDevice = QAndroidJniObject::callStaticObjectMethod("android/view/InputDevice", "getDevice", "(I)Landroid/view/InputDevice;", buff[i]);
         int sources = inputDevice.callMethod<jint>("getSources", "()I");
@@ -97,9 +98,9 @@ QMap<QString, Joystick*> JoystickAndroid::discover(MultiVehicleManager* _multiVe
         QString id = inputDevice.callObjectMethod("getDescriptor", "()Ljava/lang/String;").toString();
         QString name = inputDevice.callObjectMethod("getName", "()Ljava/lang/String;").toString();
 
+        names.push_back(name);
 
-        if (joystickFound) { //skipping {
-            qWarning() << "Skipping joystick:" << name;
+        if (ret.contains(name)) {
             continue;
         }
 
@@ -121,7 +122,14 @@ QMap<QString, Joystick*> JoystickAndroid::discover(MultiVehicleManager* _multiVe
         qCDebug(JoystickLog) << "\t" << name << "id:" << buff[i] << "axes:" << axisCount << "buttons:" << buttonCount;
 
         ret[name] = new JoystickAndroid(name, axisCount, buttonCount, buff[i], _multiVehicleManager);
-        joystickFound = true;
+    }
+
+    for (auto i = ret.begin(); i != ret.end();) {
+        if (!names.contains(i.key())) {
+            i = ret.erase(i);
+        } else {
+            i++;
+        }
     }
 
     env->ReleaseIntArrayElements(jarr, buff, 0);

src/Joystick/JoystickManager.cc

@@ -1,6 +1,6 @@
 /****************************************************************************
  *
- *   (c) 2009-2016 QGROUNDCONTROL PROJECT <http://www.qgroundcontrol.org>
+ *   (c) 2009-2019 QGROUNDCONTROL PROJECT <http://www.qgroundcontrol.org>
  *
  * QGroundControl is licensed according to the terms in the file
  * COPYING.md in the root of the source code directory.
@@ -29,8 +29,8 @@ const char * JoystickManager::_settingsKeyActiveJoystick =  "ActiveJoystick";
 
 JoystickManager::JoystickManager(QGCApplication* app, QGCToolbox* toolbox)
     : QGCTool(app, toolbox)
-    , _activeJoystick(NULL)
-    , _multiVehicleManager(NULL)
+    , _activeJoystick(nullptr)
+    , _multiVehicleManager(nullptr)
 {
 }
 
@@ -54,18 +54,17 @@ void JoystickManager::setToolbox(QGCToolbox *toolbox)
 
 void JoystickManager::init() {
 #ifdef __sdljoystick__
-    if (JoystickSDL::init()) {
-        _setActiveJoystickFromSettings();
-        connect(&_joystickCheckTimer, &QTimer::timeout, this, &JoystickManager::_updateAvailableJoysticks);
-        _joystickCheckTimer.start(250);
+    if (!JoystickSDL::init()) {
+        return;
     }
-#elif defined(__android__)
-    if (JoystickAndroid::init()) {
     _setActiveJoystickFromSettings();
-        connect(&_joystickCheckTimer, &QTimer::timeout, this, &JoystickManager::_updateAvailableJoysticks);
-        _joystickCheckTimer.start(250);
+#elif defined(__android__)
+    if (!JoystickAndroid::init()) {
+        return;
     }
 #endif
+    connect(&_joystickCheckTimer, &QTimer::timeout, this, &JoystickManager::_updateAvailableJoysticks);
+    _joystickCheckTimer.start(1000);
 }
 
 void JoystickManager::_setActiveJoystickFromSettings(void)
@@ -81,7 +80,7 @@ void JoystickManager::_setActiveJoystickFromSettings(void)
 
     if (_activeJoystick && !newMap.contains(_activeJoystick->name())) {
         qCDebug(JoystickManagerLog) << "Active joystick removed";
-        setActiveJoystick(NULL);
+        setActiveJoystick(nullptr);
     }
 
     // Check to see if our current mapping contains any joysticks that are not in the new mapping
@@ -100,7 +99,7 @@ void JoystickManager::_setActiveJoystickFromSettings(void)
     emit availableJoysticksChanged();
 
     if (!_name2JoystickMap.count()) {
-        setActiveJoystick(NULL);
+        setActiveJoystick(nullptr);
         return;
     }
 
@@ -126,7 +125,7 @@ void JoystickManager::setActiveJoystick(Joystick* joystick)
 {
     QSettings settings;
 
-    if (joystick != NULL && !_name2JoystickMap.contains(joystick->name())) {
+    if (joystick != nullptr && !_name2JoystickMap.contains(joystick->name())) {
         qCWarning(JoystickManagerLog) << "Set active not in map" << joystick->name();
         return;
     }
@@ -141,7 +140,7 @@ void JoystickManager::setActiveJoystick(Joystick* joystick)
     
     _activeJoystick = joystick;
     
-    if (_activeJoystick != NULL) {
+    if (_activeJoystick != nullptr) {
         qCDebug(JoystickManagerLog) << "Set active:" << _activeJoystick->name();
 
         settings.beginGroup(_settingsGroup);
@@ -208,8 +207,6 @@ void JoystickManager::_updateAvailableJoysticks(void)
         }
     }
 #elif defined(__android__)
-    /*
-     * TODO: Investigate Android events for Joystick hot plugging
-     */
+    _setActiveJoystickFromSettings();
 #endif
 }