Add KDDockWidgets::initPlatform()

Instead of using the static variable, which is initialized before
having QApplication.

Will allow us to remove the QTimer from Platform init

src/CMakeLists.txt

@@ -22,6 +22,7 @@ add_definitions(-DQT_NO_SIGNALS_SLOTS_KEYWORDS
 )
 
 set(DOCKSLIBS_SRCS
+    KDDockWidgets.cpp
     Config.cpp
     Config.h
     Qt5Qt6Compat_p.h

src/KDDockWidgets.cpp

@@ -0,0 +1,33 @@
+/*
+  This file is part of KDDockWidgets.
+
+  SPDX-FileCopyrightText: 2019-2022 Klarälvdalens Datakonsult AB, a KDAB Group company <info@kdab.com>
+  Author: Sérgio Martins <sergio.martins@kdab.com>
+
+  SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only
+
+  Contact KDAB at <info@kdab.com> for commercial licensing options.
+*/
+
+
+#include "KDDockWidgets.h"
+
+#include "qtwidgets/Platform_qtwidgets.h"
+#include "qtquick/Platform_qtquick.h"
+
+#include <QDebug>
+
+void KDDockWidgets::initFrontend(FrontendType type)
+{
+    if (Platform::instance())
+        return;
+
+    switch (type) {
+    case FrontendType::QtWidgets:
+        new Platform_qtwidgets();
+        break;
+    case FrontendType::QtQuick:
+        // new Platform_qtquick(); // TODOv2
+        break;
+    }
+}

src/KDDockWidgets.h

@@ -60,12 +60,12 @@ enum MainWindowOption {
 Q_DECLARE_FLAGS(MainWindowOptions, MainWindowOption)
 Q_ENUM_NS(MainWindowOptions)
 
-enum class FrontEndType
+enum class FrontendType
 {
     QtWidgets = 1,
     QtQuick
 };
-Q_ENUM_NS(FrontEndType)
+Q_ENUM_NS(FrontendType)
 
 ///@internal
 ///@brief Describes some sizing strategies for the layouting engine.
@@ -310,7 +310,11 @@ inline QString locationStr(Location loc)
 
     return QString();
 }
-}
+
+/// @brief Initializes the desired frontend
+void DOCKS_EXPORT initFrontend(FrontendType);
+
+} // end namespace
 
 QT_BEGIN_NAMESPACE
 ///@internal

src/Platform.cpp

@@ -10,6 +10,7 @@
 */
 
 #include "Platform.h"
+
 #include <qglobal.h>
 #include <QDebug>
 
@@ -19,6 +20,7 @@ static Platform *s_platform = nullptr;
 
 Platform::Platform()
 {
+    Q_ASSERT(!s_platform);
     s_platform = this;
 }
 

src/qtcommon/Platform_qt.cpp

@@ -13,6 +13,7 @@
 #include "Window_qt.h"
 
 #include <QWindow>
+#include <QDebug>
 #include <QGuiApplication>
 
 using namespace KDDockWidgets;
@@ -20,6 +21,8 @@ using namespace KDDockWidgets;
 
 Platform_qt::Platform_qt()
 {
+    if (!qApp)
+        qWarning() << "Please call KDDockWidgets::initPlatform() after QGuiApplication";
 }
 
 Platform_qt::~Platform_qt()

src/qtquick/Platform_qtquick.cpp

@@ -22,8 +22,6 @@
 #include <QTimer>
 #include <QWindow>
 
-static KDDockWidgets::Platform_qtquick s_platformQtQuick;
-
 using namespace KDDockWidgets;
 
 

src/qtwidgets/Platform_qtwidgets.cpp

@@ -22,7 +22,6 @@
 
 #include <memory.h>
 
-static KDDockWidgets::Platform_qtwidgets s_platformQtWidgets;
 
 using namespace KDDockWidgets;