Use icons from theme. Qt already handles this in a nice way

src/mirall/application.cpp

@@ -94,7 +94,7 @@ void Application::setupActions()
 void Application::setupSystemTray()
 {
     _tray = new QSystemTrayIcon(this);
-    _tray->setIcon(QIcon(FOLDER_ICON));
+    _tray->setIcon(QIcon::fromTheme(FOLDER_ICON));
     _tray->show();
 }
 
@@ -204,7 +204,7 @@ void Application::slotFolderSyncStarted()
     _folderSyncCount++;
 
     if (_folderSyncCount > 0) {
-        _tray->setIcon(QIcon(FOLDER_SYNC_ICON));
+        _tray->setIcon(QIcon::fromTheme(FOLDER_SYNC_ICON));
     }
 }
 
@@ -213,7 +213,7 @@ void Application::slotFolderSyncFinished()
     _folderSyncCount--;
 
     if (_folderSyncCount < 1) {
-        _tray->setIcon(QIcon(FOLDER_ICON));
+        _tray->setIcon(QIcon::fromTheme(FOLDER_ICON));
     }
 }
 

src/mirall/constants.h

@@ -15,8 +15,8 @@
 #ifndef MIRALL_CONSTANTS_H
 #define MIRALL_CONSTANTS_H
 
-#define FOLDER_ICON "/usr/share/icons/oxygen/48x48/places/folder-favorites.png"
-#define FOLDER_SYNC_ICON "/usr/share/icons/oxygen/48x48/actions/folder-sync.png"
-#define FOLDER_SYNC_ERROR "/usr/share/icons/oxygen/48x48/places/folder-important.png"
+#define FOLDER_ICON "folder-favorites"
+#define FOLDER_SYNC_ICON "folder-sync"
+#define FOLDER_SYNC_ERROR "folder-important"
 
 #endif

src/mirall/folder.cpp

@@ -35,9 +35,9 @@ Folder::Folder(const QString &alias, const QString &path, QObject *parent)
       _pollInterval(DEFAULT_POLL_INTERVAL_SEC),
       _alias(alias)
 {
-    _openAction = new QAction(QIcon(FOLDER_ICON), path, this);
+    _openAction = new QAction(QIcon::fromTheme(FOLDER_ICON), path, this);
     _openAction->setIconVisibleInMenu(true);
-    _openAction->setIcon(QIcon(FOLDER_ICON));
+    _openAction->setIcon(QIcon::fromTheme(FOLDER_ICON));
 
     QObject::connect(_openAction, SIGNAL(triggered(bool)), SLOT(slotOpenFolder()));
 
@@ -109,13 +109,13 @@ void Folder::slotSyncStarted()
 {
     // disable events until syncing is done
     _watcher->setEventsEnabled(false);
-    _openAction->setIcon(QIcon(FOLDER_SYNC_ICON));
+    _openAction->setIcon(QIcon::fromTheme(FOLDER_SYNC_ICON));
 }
 
 void Folder::slotSyncFinished()
 {
     _watcher->setEventsEnabled(true);
-    _openAction->setIcon(QIcon(FOLDER_ICON));
+    _openAction->setIcon(QIcon::fromTheme(FOLDER_ICON));
     // reenable the poll timer
     qDebug() << "* " << path() << "Poll timer enabled";
     _pollTimer->start();