MythMusic: Add an exit prompt to the import screen

This asks if you are sure you want to exit the import tracks screen if there
are tracks that haven't been imported yet. Once to often I've edited some
tracks metadata that are waiting to be imported only to accidentally exit
out of the screen before they've been imported.

mythplugins/mythmusic/mythmusic/importmusic.cpp

@@ -210,6 +210,31 @@ bool ImportMusicDialog::keyPressEvent(QKeyEvent *event)
         {
             showMenu();
         }
+        else if (action == "ESCAPE" && !GetMythMainWindow()->IsExitingToMain())
+        {
+            bool found = false;
+            if (!m_tracks->empty())
+            {
+                uint track = 0;
+                while (track < m_tracks->size())
+                {
+                    if (m_tracks->at(track)->isNewTune)
+                    {
+                        found = true;
+                        break;
+                    }
+                    track++;
+                }
+
+                if (found)
+                {
+                    QString msg = tr("You might have unsaved changes.\nAre you sure you want to exit this screen?");
+                    ShowOkPopup(msg, this, SLOT(doExit(bool)), true);
+                }
+            }
+
+            handled = found;
+        }
         else if (action == "1")
         {
             setCompilation();
@@ -313,6 +338,12 @@ bool ImportMusicDialog::Create()
     return true;
 }
 
+void ImportMusicDialog::doExit(bool ok)
+{
+    if (ok)
+        Close();
+}
+
 void ImportMusicDialog::locationPressed()
 {
     MythScreenStack *popupStack = GetMythMainWindow()->GetStack("popup stack");

mythplugins/mythmusic/mythmusic/importmusic.h

@@ -66,6 +66,7 @@ class ImportMusicDialog : public MythScreenType
     void prevPressed(void);
     void showEditMetadataDialog(void);
     void startScan(void);
+    void doExit(bool ok);
 
     // popup menu
     void showMenu(void);