#4116 PdmUiListView: Scroll to the first selected item when activated

This solution does not always work, but scrolls to the first selected item in most cases

Fwk/AppFwk/cafTests/cafTestApplication/ManyGroups.cpp

@@ -1,6 +1,7 @@
 
 #include "ManyGroups.h"
 #include "cafPdmUiTreeSelectionEditor.h"
+#include "cafPdmUiListEditor.h"
 
 CAF_PDM_SOURCE_INIT(ManyGroups, "LargeObject");
 
@@ -34,6 +35,9 @@ ManyGroups::ManyGroups()
     m_multiSelectList.v().push_back("First");
     m_multiSelectList.v().push_back("Second");
     m_multiSelectList.v().push_back("Third");
+
+    CAF_PDM_InitField(&m_singleStringWithManySelectableItems, "m_singleStringWithManySelectableItems", QString(""), "Text with many items", "", "Text tooltip", "");
+    m_singleStringWithManySelectableItems.uiCapability()->setUiEditorTypeName(caf::PdmUiListEditor::uiEditorTypeName());
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -62,6 +66,18 @@ QList<caf::PdmOptionItemInfo> ManyGroups::calculateValueOptions(const caf::PdmFi
 {
     QList<caf::PdmOptionItemInfo> options;
 
+    // Test code used to switch between two lists with different content, but same item count
+    if (fieldNeedingOptions == &m_singleStringWithManySelectableItems)
+    {
+        for (int i = 0; i < 100; i++)
+        {
+            QString text = QString("item %1").arg(i);
+            options.push_back(caf::PdmOptionItemInfo(text, text));
+        }
+
+        return options;
+    }
+
     // Test code used to switch between two lists with different content, but same item count
     if (fieldNeedingOptions == &m_multiSelectList)
     {

Fwk/AppFwk/cafTests/cafTestApplication/ManyGroups.h

@@ -18,6 +18,7 @@ public:
     caf::PdmProxyValueField<double> m_proxyDoubleField;
 
     caf::PdmField<std::vector<QString> > m_multiSelectList;
+    caf::PdmField<QString> m_singleStringWithManySelectableItems;
 
     caf::PdmField<bool>     m_toggleField;
     caf::PdmFieldHandle* objectToggleField() override;

Fwk/AppFwk/cafUserInterface/cafPdmUiFormLayoutObjectEditor.cpp

@@ -41,6 +41,7 @@
 #include "cafPdmUiFieldEditorHandle.h"
 #include "cafPdmUiFieldEditorHelper.h"
 #include "cafPdmUiFieldHandle.h"
+#include "cafPdmUiListEditor.h"
 #include "cafPdmUiObjectHandle.h"
 #include "cafPdmUiOrdering.h"
 #include "cafPdmXmlObjectHandle.h"
@@ -49,8 +50,9 @@
 
 #include "QMinimizePanel.h"
 
-#include <QGridLayout>
+#include <QCoreApplication>
 #include <QFrame>
+#include <QGridLayout>
 
 //--------------------------------------------------------------------------------------------------
 /// 
@@ -468,6 +470,19 @@ void caf::PdmUiFormLayoutObjectEditor::configureAndUpdateUi(const QString& uiCon
     {
         uiObject->onEditorWidgetsCreated();
     }
+
+    // Process events to make sure the layout has completed before scrolling the list editor to current item
+    // If this step is omitted, the scrollTo method ends up at arbitrary positions
+    qApp->processEvents();
+
+     for (it = m_fieldViews.begin(); it != m_fieldViews.end(); ++it)
+     {
+         auto myObj = dynamic_cast<PdmUiListEditor*>(it->second);
+         if (myObj)
+         {
+             myObj->ensureCurrentItemIsVisible();
+         }
+     }
 }
 
 //--------------------------------------------------------------------------------------------------

Fwk/AppFwk/cafUserInterface/cafPdmUiListEditor.cpp

@@ -34,7 +34,6 @@
 //
 //##################################################################################################
 
-
 #include "cafPdmUiListEditor.h"
 
 #include "cafPdmUiDefaultObjectEditor.h"
@@ -138,7 +137,8 @@ CAF_PDM_UI_FIELD_EDITOR_SOURCE_INIT(PdmUiListEditor);
 //--------------------------------------------------------------------------------------------------
 PdmUiListEditor::PdmUiListEditor() :
     m_isEditOperationsAvailable(true),
-    m_optionItemCount(0)
+    m_optionItemCount(0),
+    m_isScrollToItemAllowed(true)
 {
 }
 
@@ -149,6 +149,21 @@ PdmUiListEditor::~PdmUiListEditor()
 {
 }
 
+//--------------------------------------------------------------------------------------------------
+/// 
+//--------------------------------------------------------------------------------------------------
+void PdmUiListEditor::ensureCurrentItemIsVisible()
+{
+    if (m_isScrollToItemAllowed)
+    {
+        QModelIndex mi = m_listView->currentIndex();
+        if (mi.isValid())
+        {
+            m_listView->scrollTo(mi);
+        }
+    }
+}
+
 //--------------------------------------------------------------------------------------------------
 /// 
 //--------------------------------------------------------------------------------------------------
@@ -266,6 +281,8 @@ void PdmUiListEditor::configureAndUpdateUi(const QString& uiConfigName)
 
         m_listView->selectionModel()->blockSignals(false);
     }
+
+    //ensureCurrentItemIsVisible();
 }
 
 //--------------------------------------------------------------------------------------------------
@@ -306,6 +323,8 @@ void PdmUiListEditor::slotSelectionChanged(const QItemSelection & selected, cons
 {
     if (m_optionItemCount == 0) return;
 
+    m_isScrollToItemAllowed = false;
+
     QVariant fieldValue = uiField()->uiValue();
     if (fieldValue.type() == QVariant::Int || fieldValue.type() == QVariant::UInt)
     {
@@ -359,6 +378,8 @@ void PdmUiListEditor::slotSelectionChanged(const QItemSelection & selected, cons
 
         this->setValueToField(valuesToSetInField);
     }
+
+    m_isScrollToItemAllowed = true;
 }
 
 //--------------------------------------------------------------------------------------------------

Fwk/AppFwk/cafUserInterface/cafPdmUiListEditor.h

@@ -81,6 +81,8 @@ public:
     PdmUiListEditor(); 
     ~PdmUiListEditor() override; 
 
+    void        ensureCurrentItemIsVisible();
+
 protected:
     QWidget*    createEditorWidget(QWidget * parent) override;
     QWidget*    createLabelWidget(QWidget * parent) override;
@@ -102,8 +104,9 @@ private:
     QPointer<QLabel>              m_label;
     QPointer<QStringListModel>    m_model;
 
-    bool                    m_isEditOperationsAvailable;
+    bool m_isEditOperationsAvailable;
-    int                     m_optionItemCount;
+    int  m_optionItemCount;
+    bool m_isScrollToItemAllowed;
 };