added screen manager

src/actions/switchscreenaction.h

@@ -2,6 +2,7 @@
 
 // local includes
 #include "actioninterface.h"
+#include "screenmanager.h"
 
 namespace espgui {
 template<typename Tscreen, typename ...Targs>

src/screenmanager.cpp

@@ -0,0 +1,8 @@
+#include "screenmanager.h"
+
+namespace espgui {
+
+std::unique_ptr<Display> currentDisplay;
+std::function<void()> changeScreenCallback;
+
+} // namespace espgui

src/screenmanager.h

@@ -0,0 +1,49 @@
+#pragma once
+
+// system includes
+#include <memory>
+#include <functional>
+#include <utility>
+
+// local includes
+#include "display.h"
+
+namespace espgui {
+
+extern std::unique_ptr<Display> currentDisplay;
+
+inline void deconstructScreen()
+{
+    if (currentDisplay)
+    {
+        currentDisplay->stop();
+        //currentDisplay->~Display();
+        currentDisplay = nullptr;
+    }
+}
+
+template<typename T, typename... Args>
+void switchScreenImpl(Args&&... args)
+{
+    deconstructScreen();
+
+    std::unique_ptr<T> ptr = std::make_unique<T>(std::forward<Args>(args)...);
+    currentDisplay = std::move(ptr);
+    currentDisplay->start();
+    currentDisplay->initScreen();
+    currentDisplay->update();
+    currentDisplay->redraw();
+}
+
+extern std::function<void()> changeScreenCallback;
+
+template<typename T, typename... Args>
+void switchScreen(Args&&... args)
+{
+    if (currentDisplay)
+        changeScreenCallback = [&args...](){ switchScreenImpl<T>(std::forward<Args>(args)...); };
+    else
+        switchScreenImpl<T>(std::forward<Args>(args)...);
+}
+
+} // namespace espgui