From daee2998c556884c5abf16bf87cb84d5fd47cd8b Mon Sep 17 00:00:00 2001
From: Romain Goyet <romain.goyet@numworks.com>
Date: Wed, 9 May 2018 17:14:04 +0200
Subject: [PATCH] [escher] Add a ScrollViewDelegate

---
 escher/include/escher/scroll_view_data_source.h | 15 +++++++++++++--
 escher/include/escher/scrollable_view.h         |  2 +-
 escher/src/scroll_view_data_source.cpp          | 13 +++----------
 3 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/escher/include/escher/scroll_view_data_source.h b/escher/include/escher/scroll_view_data_source.h
index 132888264..61a97aa87 100644
--- a/escher/include/escher/scroll_view_data_source.h
+++ b/escher/include/escher/scroll_view_data_source.h
@@ -3,12 +3,23 @@
 
 #include <kandinsky.h>
 
+class ScrollViewDataSource;
+
+class ScrollViewDelegate {
+public:
+  virtual void scrollViewDidChangeOffset(ScrollViewDataSource * scrollViewDataSource) = 0;
+};
+
 class ScrollViewDataSource {
 public:
-  ScrollViewDataSource();
-  KDPoint offset() const;
+  ScrollViewDataSource() : m_delegate(nullptr), m_offset(KDPointZero) {}
+  KDPoint offset() const { return m_offset; }
   bool setOffset(KDPoint offset);
+  void setScrollViewDelegate(ScrollViewDelegate * delegate) {
+    m_delegate = delegate;
+  }
 private:
+  ScrollViewDelegate * m_delegate;
   KDPoint m_offset;
 };
 
diff --git a/escher/include/escher/scrollable_view.h b/escher/include/escher/scrollable_view.h
index a6b08bf36..73d6b7067 100644
--- a/escher/include/escher/scrollable_view.h
+++ b/escher/include/escher/scrollable_view.h
@@ -6,7 +6,7 @@
 
 class ScrollableView : public Responder, public ScrollView {
 public:
- ScrollableView(Responder * parentResponder, View * view, ScrollViewDataSource * dataSource);
+  ScrollableView(Responder * parentResponder, View * view, ScrollViewDataSource * dataSource);
   bool handleEvent(Ion::Events::Event event) override;
   void reloadScroll(bool forceRelayout = false);
 protected:
diff --git a/escher/src/scroll_view_data_source.cpp b/escher/src/scroll_view_data_source.cpp
index 334a06e00..3dbf32dc1 100644
--- a/escher/src/scroll_view_data_source.cpp
+++ b/escher/src/scroll_view_data_source.cpp
@@ -1,19 +1,12 @@
 #include <escher/scroll_view_data_source.h>
 
-ScrollViewDataSource::ScrollViewDataSource() :
-  m_offset(KDPointZero)
-{
-}
-
-KDPoint ScrollViewDataSource::offset() const {
-  return m_offset;
-}
-
 bool ScrollViewDataSource::setOffset(KDPoint offset) {
   if (offset != m_offset) {
     m_offset = offset;
+    if (m_delegate) {
+      m_delegate->scrollViewDidChangeOffset(this);
+    }
     return true;
   }
   return false;
 }
-