Introduced new screen stack to keep selected menu item when going back

CMakeLists.txt

@@ -34,6 +34,8 @@ set(headers
     src/actions/backproxyaction.h
     src/actions/dummyaction.h
     src/actions/multiaction.h
+    src/actions/pushscreenaction.h
+    src/actions/popscreenaction.h
     src/actions/setvalueaction.h
     src/actions/switchscreenaction.h
     src/actions/toggleboolaction.h

src/actions/popscreenaction.h

@@ -0,0 +1,18 @@
+#pragma once
+
+// system includes
+#include <utility>
+
+// local includes
+#include "actioninterface.h"
+#include "screenmanager.h"
+
+namespace espgui {
+
+class PopScreenAction : public virtual ActionInterface
+{
+public:
+    void triggered() override { popScreen(); }
+};
+
+} // namespace espgui

src/actions/pushscreenaction.h

@@ -0,0 +1,59 @@
+#pragma once
+
+// system includes
+#include <utility>
+
+// local includes
+#include "actioninterface.h"
+#include "screenmanager.h"
+
+namespace espgui {
+
+template<typename Tscreen>
+class PushScreenAction : public virtual ActionInterface
+{
+public:
+    void triggered() override { pushScreen<Tscreen>(); }
+};
+
+template<typename Tscreen, typename ...Targs>
+class PushScreenActionArgs;
+
+template<typename Tscreen, typename T1>
+class PushScreenActionArgs<Tscreen, T1> : public virtual ActionInterface
+{
+public:
+    PushScreenActionArgs(T1 &&arg1) :
+        m_arg1{std::move<T1>(arg1)}
+    {}
+    PushScreenActionArgs(const T1 &arg1) :
+        m_arg1{arg1}
+    {}
+
+    void triggered() override { pushScreen<Tscreen>(std::move(m_arg1)); }
+
+private:
+    T1 m_arg1;
+};
+
+template<typename Tscreen, typename T1, typename T2>
+class PushScreenActionArgs<Tscreen, T1, T2> : public virtual ActionInterface
+{
+public:
+    PushScreenActionArgs(T1 &&arg1, T2 &&arg2) :
+        m_arg1{std::move<T1>(arg1)},
+        m_arg2{std::move<T2>(arg2)}
+    {}
+    PushScreenActionArgs(const T1 &arg1, const T2 &arg2) :
+        m_arg1{arg1},
+        m_arg2{arg2}
+    {}
+
+    void triggered() override { pushScreen<Tscreen>(std::move(m_arg1), std::move(m_arg2)); }
+
+private:
+    T1 m_arg1;
+    T2 m_arg2;
+};
+
+} // namespace espgui

src/actions/switchscreenaction.h

@@ -8,6 +8,7 @@
 #include "screenmanager.h"
 
 namespace espgui {
+
 template<typename Tscreen>
 class SwitchScreenAction : public virtual ActionInterface
 {
@@ -15,7 +16,6 @@ public:
     void triggered() override { switchScreen<Tscreen>(); }
 };
 
-
 template<typename Tscreen, typename ...Targs>
 class SwitchScreenActionArgs;
 
@@ -55,4 +55,5 @@ private:
     T1 m_arg1;
     T2 m_arg2;
 };
+
 } // namespace espgui

src/menudisplay.cpp

@@ -8,8 +8,8 @@ void MenuDisplay::start()
 {
     Base::start();
 
-    m_selectedIndex = 0;
+//    m_selectedIndex = 0;
-    m_scrollOffset = 0;
+//    m_scrollOffset = 0;
 
     m_rotateOffset = 0;
     m_pressed = false;

src/menudisplay.h

@@ -138,8 +138,8 @@ private:
 
     std::array<const Icon<24, 24> *, rowCount> m_icons;
 
-    int m_selectedIndex;
+    int m_selectedIndex{};
-    int m_scrollOffset;
+    int m_scrollOffset{};
     int m_highlightedIndex;
 
     int m_rotateOffset;

src/screenmanager.cpp

@@ -3,6 +3,8 @@
 namespace espgui {
 
 std::unique_ptr<Display> currentDisplay;
+std::stack<std::unique_ptr<Display>> displayStack;
+
 std::function<void()> changeScreenCallback;
 
 void deconstructScreen()
@@ -14,4 +16,29 @@ void deconstructScreen()
     }
 }
 
+void pushScreenInternal()
+{
+    if (currentDisplay)
+    {
+        currentDisplay->stop();
+        displayStack.push(std::move(currentDisplay));
+        assert(!currentDisplay);
+    }
+}
+
+void popScreen()
+{
+    deconstructScreen();
+
+    if (displayStack.empty())
+        return;
+
+    currentDisplay = std::move(displayStack.top());
+    displayStack.pop();
+    currentDisplay->start();
+    currentDisplay->initScreen();
+    currentDisplay->update();
+    currentDisplay->redraw();
+}
+
 } // namespace espgui

src/screenmanager.h

@@ -4,6 +4,7 @@
 #include <memory>
 #include <functional>
 #include <utility>
+#include <stack>
 
 // local includes
 #include "display.h"
@@ -12,8 +13,16 @@ namespace espgui {
 
 extern std::unique_ptr<Display> currentDisplay;
 
+extern std::stack<std::unique_ptr<Display>> displayStack;
+
+extern std::function<void()> changeScreenCallback;
+
 void deconstructScreen();
 
+void pushScreenInternal();
+
+void popScreen();
+
 template<typename T, typename... Args>
 void switchScreenImpl(Args... args)
 {
@@ -38,8 +47,6 @@ void switchScreenRefImpl(Args&&... args)
     currentDisplay->redraw();
 }
 
-extern std::function<void()> changeScreenCallback;
-
 template<typename T, typename... Args>
 void switchScreen(Args... args)
 {
@@ -58,4 +65,46 @@ void switchScreenRef(Args&&... args)
         switchScreenRefImpl<T>(std::forward<Args>(args)...);
 }
 
+template<typename T, typename... Args>
+void pushScreenImpl(Args... args)
+{
+    pushScreenInternal();
+
+    currentDisplay = std::make_unique<T>(args...);
+    currentDisplay->start();
+    currentDisplay->initScreen();
+    currentDisplay->update();
+    currentDisplay->redraw();
+}
+
+template<typename T, typename... Args>
+void pushScreenRefImpl(Args&&... args)
+{
+    pushScreenInternal();
+
+    currentDisplay = std::make_unique<T>(std::forward<Args>(args)...);
+    currentDisplay->start();
+    currentDisplay->initScreen();
+    currentDisplay->update();
+    currentDisplay->redraw();
+}
+
+template<typename T, typename... Args>
+void pushScreen(Args... args)
+{
+    if (currentDisplay)
+        changeScreenCallback = [args...](){ pushScreenImpl<T>(args...); };
+    else
+        pushScreenImpl<T>(args...);
+}
+
+template<typename T, typename... Args>
+void pushScreenRef(Args&&... args)
+{
+    if (currentDisplay)
+        changeScreenCallback = [args...](){ pushScreenRefImpl<T>(std::forward<Args>(args)...); };
+    else
+        pushScreenRefImpl<T>(std::forward<Args>(args)...);
+}
+
 } // namespace espgui