From daf4132dec7f59bf0f5357aaeae34fbc02c35d67 Mon Sep 17 00:00:00 2001
From: Magne Sjaastad <magne.sjaastad@ceetronsolutions.com>
Date: Fri, 20 Sep 2019 14:18:52 +0200
Subject: [PATCH] #4744 AppFwk : Auto scroll to first checked item

---
 .../cafPdmUiTreeSelectionEditor.cpp           | 48 +++++++++++++++++++
 .../cafPdmUiTreeSelectionEditor.h             |  2 +
 2 files changed, 50 insertions(+)

diff --git a/Fwk/AppFwk/cafUserInterface/cafPdmUiTreeSelectionEditor.cpp b/Fwk/AppFwk/cafUserInterface/cafPdmUiTreeSelectionEditor.cpp
index df3cdcba00..24959a67d2 100644
--- a/Fwk/AppFwk/cafUserInterface/cafPdmUiTreeSelectionEditor.cpp
+++ b/Fwk/AppFwk/cafUserInterface/cafPdmUiTreeSelectionEditor.cpp
@@ -52,6 +52,7 @@
 #include <QPalette>
 #include <QSortFilterProxyModel>
 #include <QStyleOption>
+#include <QTimer>
 #include <QTreeView>
 
 #include <algorithm>
@@ -374,6 +375,10 @@ void PdmUiTreeSelectionEditor::configureAndUpdateUi(const QString& uiConfigName)
             }
         }
     }
+
+    // It is required to use a timer here, as the layout of the widgets are handled by events
+    // Calling scrollTo() here has no effect, or scrolls to wrong location
+    QTimer::singleShot(150, this, SLOT(slotScrollToFirstCheckedItem()));
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -647,6 +652,49 @@ void PdmUiTreeSelectionEditor::slotClicked(const QModelIndex& index)
     currentChanged(index);
 }
 
+//--------------------------------------------------------------------------------------------------
+/// 
+//--------------------------------------------------------------------------------------------------
+void PdmUiTreeSelectionEditor::slotScrollToFirstCheckedItem()
+{
+    auto firstVisibleIndex = m_treeView->indexAt(m_treeView->viewport()->rect().topLeft());
+    auto lastVisibleIndex = m_treeView->indexAt(m_treeView->viewport()->rect().bottomRight());
+
+    if (!firstVisibleIndex.isValid())
+    {
+        return;
+    }
+
+    if (!lastVisibleIndex.isValid())
+    {
+        return;
+    }
+
+    for (int i = firstVisibleIndex.row(); i < lastVisibleIndex.row(); i++)
+    {
+        auto treeViewIndex = m_proxyModel->index(i, 0);
+
+        if (m_proxyModel->data(treeViewIndex, Qt::CheckStateRole).toBool())
+        {
+            // Do nothing if there is a checked and visible item in the view
+            return;
+        }
+    }
+
+    for (int i = 0; i < m_proxyModel->rowCount(); i++)
+    {
+        auto treeViewIndex = m_proxyModel->index(i, 0);
+
+        if (m_proxyModel->data(treeViewIndex, Qt::CheckStateRole).toBool())
+        {
+            // Scroll to the first checked item if no checked items are visible
+            m_treeView->scrollTo(treeViewIndex);
+
+            return;
+        }
+    }
+}
+
 //--------------------------------------------------------------------------------------------------
 ///
 //--------------------------------------------------------------------------------------------------
diff --git a/Fwk/AppFwk/cafUserInterface/cafPdmUiTreeSelectionEditor.h b/Fwk/AppFwk/cafUserInterface/cafPdmUiTreeSelectionEditor.h
index 542f5d4418..9de488f9de 100644
--- a/Fwk/AppFwk/cafUserInterface/cafPdmUiTreeSelectionEditor.h
+++ b/Fwk/AppFwk/cafUserInterface/cafPdmUiTreeSelectionEditor.h
@@ -115,6 +115,8 @@ private slots:
 
     void                slotClicked(const QModelIndex& index);
 
+    void                slotScrollToFirstCheckedItem();
+
 private:
     void                currentChanged(const QModelIndex& current);