Improved UI when no joysticks are connected. Also removed hotplugging support...

Improved UI when no joysticks are connected. Also removed hotplugging support for joysticks as it wasn't working, though SDL2 should fix that.

src/input/JoystickInput.cc

@@ -313,7 +313,7 @@ void JoystickInput::setEnabled(bool enabled)
 
 void JoystickInput::init()
 {
-    // INITIALIZE SDL Joystick support
+    // Initialize SDL Joystick support and detect number of joysticks.
     if (SDL_InitSubSystem(SDL_INIT_JOYSTICK | SDL_INIT_NOPARACHUTE) < 0) {
         printf("Couldn't initialize SimpleDirectMediaLayer: %s\n", SDL_GetError());
     }
@@ -321,16 +321,11 @@ void JoystickInput::init()
     // Enumerate joysticks and select one
     numJoysticks = SDL_NumJoysticks();
 
-    // Wait for joysticks if none are connected
-    while (numJoysticks == 0 && !done)
+    // If no joysticks are connected, there's nothing we can do, so just keep
+    // going back to sleep every second unless the program quits.
+    while (!numJoysticks && !done)
     {
-        QGC::SLEEP::msleep(400);
-        // INITIALIZE SDL Joystick support
-        if (SDL_InitSubSystem(SDL_INIT_JOYSTICK | SDL_INIT_NOPARACHUTE) < 0)
-        {
-            printf("Couldn't initialize SimpleDirectMediaLayer: %s\n", SDL_GetError());
-        }
-        numJoysticks = SDL_NumJoysticks();
+        QGC::SLEEP::sleep(1);
     }
     if (done)
     {

src/ui/JoystickWidget.cc

@@ -67,17 +67,18 @@ void JoystickWidget::initUI()
         {
             m_ui->joystickFrame->setEnabled(true);
         }
+
+        // Create the initial UI.
+        createUIForJoystick();
     }
-    // But if there're no joysticks, just disable everything.
+    // But if there're no joysticks, disable everything and hide empty UI.
     else
     {
         m_ui->enableCheckBox->setEnabled(false);
         m_ui->joystickNameComboBox->addItem(tr("No joysticks found. Connect and restart QGC to add one."));
         m_ui->joystickNameComboBox->setEnabled(false);
+        m_ui->joystickFrame->hide();
     }
-
-    // Add any missing buttons
-    createUIForJoystick();
 }
 
 void JoystickWidget::styleChanged(MainWindow::QGC_MAINWINDOW_STYLE newStyle)
@@ -225,7 +226,7 @@ void JoystickWidget::createUIForJoystick()
     }
     else
     {
-        m_ui->buttonBox->hide();
+        m_ui->axesBox->hide();
     }
 }