[escher] Create dynamic view controller

Change-Id: Ic8fe6d095666aa7af76c8d328b0bf83342a09453

escher/Makefile

@@ -8,6 +8,7 @@ objs += $(addprefix escher/src/,\
   button_row_controller.o\
   chevron_view.o\
   container.o\
+  dynamic_view_controller.o\
   editable_text_cell.o\
   even_odd_cell.o\
   even_odd_buffer_text_cell.o\

escher/include/escher.h

@@ -9,6 +9,7 @@
 #include <escher/button_row_controller.h>
 #include <escher/chevron_view.h>
 #include <escher/container.h>
+#include <escher/dynamic_view_controller.h>
 #include <escher/editable_text_cell.h>
 #include <escher/even_odd_cell.h>
 #include <escher/even_odd_buffer_text_cell.h>

escher/include/escher/alternate_empty_view_controller.h

@@ -15,6 +15,8 @@ public:
   void didBecomeFirstResponder() override;
   void viewWillAppear() override;
   void viewDidDisappear() override;
+  void loadView() override;
+  void unloadView() override;
 private:
   class ContentView : public View {
   public:

escher/include/escher/button_row_controller.h

@@ -28,6 +28,8 @@ public:
   bool setSelectedButton(int selectedButton);
   void viewWillAppear() override;
   void viewDidDisappear() override;
+  void loadView() override;
+  void unloadView() override;
 private:
   class ContentView : public View {
   public:
@@ -64,6 +66,10 @@ public:
   virtual Button * buttonAtIndex(int index, ButtonRowController::Position position) const;
   ButtonRowController * header();
   ButtonRowController * footer();
+  /* By default these two functions do not load anything. They should be
+   * overrided if the delegate dynamically allocate the button views. */
+  virtual void loadButtonView();
+  virtual void unloadButtonView();
 private:
   ButtonRowController * m_header;
   ButtonRowController * m_footer;

escher/include/escher/dynamic_view_controller.h

@@ -0,0 +1,21 @@
+#ifndef ESCHER_DYNAMIC_VIEW_CONTROLLER_H
+#define ESCHER_DYNAMIC_VIEW_CONTROLLER_H
+
+#include <escher/view_controller.h>
+
+/* Dynamic view controllers dynamically construct their views when appearring and
+ * delete them when disappearing. */
+
+class DynamicViewController : public ViewController {
+public:
+  DynamicViewController(Responder * parentResponder);
+  ~DynamicViewController();
+  View * view() override;
+  virtual void loadView() override;
+  virtual void unloadView() override;
+private:
+  virtual View * createView() = 0;
+  View * m_view;
+};
+
+#endif

escher/include/escher/modal_view_controller.h

@@ -17,6 +17,8 @@ public:
   bool isDisplayingModal();
   void viewWillAppear() override;
   void viewDidDisappear() override;
+  void loadView() override;
+  void unloadView() override;
 private:
   class ContentView : public View {
   public:

escher/include/escher/stack_view_controller.h

@@ -23,6 +23,8 @@ public:
   void didBecomeFirstResponder() override;
   void viewWillAppear() override;
   void viewDidDisappear() override;
+  void loadView() override;
+  void unloadView() override;
 private:
   class ControllerView : public View {
   public:

escher/include/escher/tab_view_controller.h

@@ -16,9 +16,12 @@ public:
   const char * tabName(uint8_t index);
   bool handleEvent(Ion::Events::Event event) override;
   void didBecomeFirstResponder() override;
+  void didEnterResponderChain(Responder * previousResponder) override;
   void willResignFirstResponder() override;
   void viewWillAppear() override;
   void viewDidDisappear() override;
+  void loadView() override;
+  void unloadView() override;
 private:
   class ContentView : public View {
   public:

escher/include/escher/view.h

@@ -25,6 +25,7 @@ class View {
   friend class Window;
 public:
   View();
+  virtual ~View();
 
   /* The drawRect method should be implemented by each View subclass. In a
    * typical drawRect implementation, a subclass will make drawing calls to the

escher/include/escher/view_controller.h

@@ -32,6 +32,8 @@ public:
   ViewController(Responder * parentResponder);
   virtual const char * title();
   virtual View * view() = 0;
+  virtual void loadView();
+  virtual void unloadView();
   virtual void viewWillAppear();
   virtual void viewDidDisappear();
 };

escher/src/alternate_empty_view_controller.cpp

@@ -86,3 +86,11 @@ void AlternateEmptyViewController::viewDidDisappear() {
     m_contentView.mainViewController()->viewDidDisappear();
   }
 }
+
+void AlternateEmptyViewController::loadView() {
+  m_contentView.mainViewController()->loadView();
+}
+
+void AlternateEmptyViewController::unloadView() {
+  m_contentView.mainViewController()->unloadView();
+}

escher/src/app.cpp

@@ -91,13 +91,12 @@ const Container * App::container() const {
 }
 
 void App::didBecomeActive(Window * window) {
+  m_modalViewController.loadView();
   View * view = m_modalViewController.view();
   assert(m_modalViewController.app() == this);
   window->setContentView(view);
   m_modalViewController.viewWillAppear();
-  if (m_firstResponder == nullptr) {
-    setFirstResponder(&m_modalViewController);
-  }
+  setFirstResponder(&m_modalViewController);
   window->redraw();
 }
 
@@ -105,5 +104,7 @@ void App::willBecomeInactive() {
   if (m_modalViewController.isDisplayingModal()) {
     dismissModalViewController();
   }
+  setFirstResponder(nullptr);
   m_modalViewController.viewDidDisappear();
+  m_modalViewController.unloadView();
 }

escher/src/button_row_controller.cpp

@@ -26,6 +26,12 @@ ButtonRowController * ButtonRowDelegate::header() {
   return m_header;
 }
 
+void ButtonRowDelegate::loadButtonView() {
+}
+
+void ButtonRowDelegate::unloadButtonView() {
+}
+
 ButtonRowController::ContentView::ContentView(ViewController * mainViewController, ButtonRowDelegate * delegate, Position position, Style style) :
   View(),
   m_mainViewController(mainViewController),
@@ -231,3 +237,13 @@ void ButtonRowController::viewWillAppear() {
 void ButtonRowController::viewDidDisappear() {
   m_contentView.mainViewController()->viewDidDisappear();
 }
+
+void ButtonRowController::loadView() {
+  m_contentView.buttonRowDelegate()->loadButtonView();
+  m_contentView.mainViewController()->loadView();
+}
+
+void ButtonRowController::unloadView() {
+  m_contentView.buttonRowDelegate()->unloadButtonView();
+  m_contentView.mainViewController()->unloadView();
+}

escher/src/dynamic_view_controller.cpp

@@ -0,0 +1,32 @@
+#include <escher/dynamic_view_controller.h>
+#include <escher/app.h>
+#include <assert.h>
+
+DynamicViewController::DynamicViewController(Responder * parentResponder) :
+  ViewController(parentResponder),
+  m_view(nullptr)
+{
+}
+
+DynamicViewController::~DynamicViewController() {
+  if (m_view) {
+    delete m_view;
+    m_view = nullptr;
+  }
+}
+
+View * DynamicViewController::view() {
+  assert(m_view != nullptr);
+  return m_view;
+}
+
+void DynamicViewController::loadView() {
+  assert(m_view == nullptr);
+  m_view = createView();
+}
+
+void DynamicViewController::unloadView() {
+  assert(m_view != nullptr);
+  delete m_view;
+  m_view = nullptr;
+}

escher/src/modal_view_controller.cpp

@@ -17,7 +17,9 @@ ModalViewController::ContentView::ContentView() :
 }
 
 void ModalViewController::ContentView::setMainView(View * regularView) {
-  m_regularView = regularView;
+  if (m_regularView != regularView) {
+    m_regularView = regularView;
+  }
 }
 
 int ModalViewController::ContentView::numberOfSubviews() const {
@@ -96,9 +98,6 @@ ModalViewController::ModalViewController(Responder * parentResponder, ViewContro
 }
 
 View * ModalViewController::view() {
-  if (m_contentView.subviewAtIndex(0) == nullptr) {
-    m_contentView.setMainView(m_regularViewController->view());
-  }
   return &m_contentView;
 }
 
@@ -112,6 +111,7 @@ void ModalViewController::displayModalViewController(ViewController * vc, float
   vc->setParentResponder(this);
   m_previousResponder = app()->firstResponder();
   m_regularViewController->viewDidDisappear();
+  vc->loadView();
   m_contentView.presentModalView(vc->view(), verticalAlignment, horizontalAlignment, topMargin, leftMargin, bottomMargin, rightMargin);
   m_currentModalViewController->viewWillAppear();
   app()->setFirstResponder(vc);
@@ -119,6 +119,7 @@ void ModalViewController::displayModalViewController(ViewController * vc, float
 
 void ModalViewController::dismissModalViewController() {
   m_currentModalViewController->viewDidDisappear();
+  m_currentModalViewController->unloadView();
   m_currentModalViewController = nullptr;
   m_regularViewController->viewWillAppear();
   app()->setFirstResponder(m_previousResponder);
@@ -156,3 +157,19 @@ void ModalViewController::viewDidDisappear() {
   }
   m_regularViewController->viewDidDisappear();
 }
+
+void ModalViewController::loadView() {
+  if (m_contentView.isDisplayingModal()) {
+    m_currentModalViewController->loadView();
+  }
+  m_regularViewController->loadView();
+  m_contentView.setMainView(m_regularViewController->view());
+  m_contentView.layoutSubviews();
+}
+
+void ModalViewController::unloadView() {
+  if (m_contentView.isDisplayingModal()) {
+    m_currentModalViewController->unloadView();
+  }
+  m_regularViewController->unloadView();
+}

escher/src/stack_view_controller.cpp

@@ -90,8 +90,9 @@ const char * StackViewController::title() {
 void StackViewController::push(ViewController * vc, KDColor textColor, KDColor backgroundColor, KDColor separatorColor) {
   m_view.pushStack(vc, textColor, backgroundColor, separatorColor);
   m_children[m_numberOfChildren++] = vc;
-  if (m_numberOfChildren > 1) {
+  if (m_numberOfChildren > 2) {
     m_children[m_numberOfChildren-2]->viewDidDisappear();
+    m_children[m_numberOfChildren-2]->unloadView();
   }
   setupActiveViewController();
 }
@@ -100,15 +101,19 @@ void StackViewController::pop() {
   m_view.popStack();
   assert(m_numberOfChildren > 0);
   ViewController * vc = m_children[m_numberOfChildren-1];
-  vc->setParentResponder(nullptr);
   m_numberOfChildren--;
   vc->viewDidDisappear();
   setupActiveViewController();
+  vc->setParentResponder(nullptr);
+  vc->unloadView();
 }
 
 void StackViewController::setupActiveViewController() {
   ViewController * vc = m_children[m_numberOfChildren-1];
   vc->setParentResponder(this);
+  if (m_numberOfChildren > 1) {
+    vc->loadView();
+  }
   m_view.setContentView(vc->view());
   vc->viewWillAppear();
   app()->setFirstResponder(vc);
@@ -133,7 +138,12 @@ View * StackViewController::view() {
 
 void StackViewController::viewWillAppear() {
   if (m_rootViewController != nullptr) {
-    push(m_rootViewController, m_textColor, m_backgroundColor, m_separatorColor);
+    /* push the m_rootViewController without setting it as first responder
+     * (which will be done in did become first responder */
+    m_view.pushStack(m_rootViewController, m_textColor, m_backgroundColor, m_separatorColor);
+    m_children[m_numberOfChildren++] = m_rootViewController;
+    m_rootViewController->setParentResponder(this);
+    m_view.setContentView(m_rootViewController->view());
     m_rootViewController = nullptr;
   }
   ViewController * vc = m_children[m_numberOfChildren-1];
@@ -148,3 +158,21 @@ void StackViewController::viewDidDisappear() {
     vc->viewDidDisappear();
   }
 }
+
+void StackViewController::loadView() {
+  if (m_rootViewController) {
+    m_rootViewController->loadView();
+  } else {
+   ViewController * vc = m_children[m_numberOfChildren-1];
+   if (m_numberOfChildren > 0 && vc) {
+     vc->loadView();
+   }
+  }
+}
+
+void StackViewController::unloadView() {
+  ViewController * vc = m_children[m_numberOfChildren-1];
+  if (m_numberOfChildren > 0 && vc) {
+    vc->unloadView();
+  }
+}

escher/src/tab_view_controller.cpp

@@ -111,10 +111,14 @@ void TabViewController::setActiveTab(int8_t i, bool forceReactive) {
   ViewController * activeVC = m_children[i];
   if (i  != m_activeChildIndex || forceReactive) {
     assert(i <= m_numberOfChildren);
+    if (i != m_activeChildIndex) {
+      activeVC->loadView();
+    }
     m_view.setActiveView(activeVC->view());
     m_view.m_tabView.setActiveIndex(i);
-    if (m_activeChildIndex >= 0) {
+    if (m_activeChildIndex >= 0 && m_activeChildIndex != i) {
       m_children[m_activeChildIndex]->viewDidDisappear();
+      m_children[m_activeChildIndex]->unloadView();
     }
     m_activeChildIndex = i;
     if (i >= 0) {
@@ -132,6 +136,10 @@ void TabViewController::setSelectedTab(int8_t i) {
   m_selectedChildIndex = i;
 }
 
+void TabViewController::didEnterResponderChain(Responder * previousResponder) {
+  setActiveTab(m_activeChildIndex, true);
+}
+
 void TabViewController::didBecomeFirstResponder() {
   setSelectedTab(m_activeChildIndex);
 }
@@ -142,13 +150,6 @@ void TabViewController::willResignFirstResponder() {
 
 
 View * TabViewController::view() {
-  // We're asked for a view!
-  // Let's populate our tabview
-  if (m_view.m_tabView.numberOfTabs() != m_numberOfChildren) {
-    for (int i=0; i<m_numberOfChildren; i++) {
-      m_view.m_tabView.addTab(m_children[i]);
-    }
-  }
   return &m_view;
 }
 
@@ -161,16 +162,26 @@ const char * TabViewController::tabName(uint8_t index) {
 }
 
 void TabViewController::viewWillAppear() {
-  if (m_activeChildIndex < 0) {
-    setActiveTab(0, true);
-  } else {
-    setActiveTab(m_activeChildIndex, true);
-  }
-  ViewController * activeVC = m_children[m_activeChildIndex];
-  activeVC->viewWillAppear();
 }
 
 void TabViewController::viewDidDisappear() {
   ViewController * activeVC = m_children[m_activeChildIndex];
   activeVC->viewDidDisappear();
 }
+
+void TabViewController::loadView() {
+  if (m_view.m_tabView.numberOfTabs() != m_numberOfChildren) {
+    for (int i=0; i<m_numberOfChildren; i++) {
+      m_view.m_tabView.addTab(m_children[i]);
+    }
+  }
+  if (m_activeChildIndex < 0) {
+    m_activeChildIndex = 0;
+  }
+  m_children[m_activeChildIndex]->loadView();
+}
+
+void TabViewController::unloadView() {
+  ViewController * activeVC = m_children[m_activeChildIndex];
+  activeVC->unloadView();
+}

escher/src/view.cpp

@@ -10,6 +10,9 @@ View::View() :
 {
 }
 
+View::~View() {
+}
+
 void View::drawRect(KDContext * ctx, KDRect rect) const {
   // By default, a view doesn't do anything
   // It's transparent!

escher/src/view_controller.cpp

@@ -14,3 +14,9 @@ void ViewController::viewWillAppear() {
 
 void ViewController::viewDidDisappear() {
 }
+
+void ViewController::loadView() {
+}
+
+void ViewController::unloadView() {
+}