Projects tree: Fix collapsing behavior of Left key

Work around a Qt issue that the left key directly jumps to the parent if
the horizontal scroll bar is not left-most.

Task-number: QTBUG-118515
Change-Id: Icfc2a58863a3847a84bca05fc2de4b28e384106c
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

2 files changed, 18 insertions, 0 deletions

diff --git a/src/libs/utils/navigationtreeview.cpp b/src/libs/utils/navigationtreeview.cpp
index 61ef04d816..5db3d5ccec 100644
--- a/src/libs/utils/navigationtreeview.cpp
+++ b/src/libs/utils/navigationtreeview.cpp
@@ -69,6 +69,23 @@ void NavigationTreeView::scrollTo(const QModelIndex &index, QAbstractItemView::S
     hBar->setValue(scrollX);
 }
 
+QModelIndex NavigationTreeView::moveCursor(CursorAction cursorAction,
+                                           Qt::KeyboardModifiers modifiers)
+{
+    if (cursorAction == MoveLeft) {
+        // work around QTBUG-118515
+        // Left key moves to parent instead of collapsing current item, if scroll position
+        // is not left-most
+        QScrollBar *sb = horizontalScrollBar();
+        QModelIndex current = currentIndex();
+        if (sb->value() != sb->minimum() && model()->hasChildren(current) && isExpanded(current)) {
+            collapse(current);
+            return current;
+        }
+    }
+    return TreeView::moveCursor(cursorAction, modifiers);
+}
+
 // This is a workaround to stop Qt from redrawing the project tree every
 // time the user opens or closes a menu when it has focus. Would be nicer to
 // fix it in Qt.
diff --git a/src/libs/utils/navigationtreeview.h b/src/libs/utils/navigationtreeview.h
index a3a0e2b07d..b4f9a19034 100644
--- a/src/libs/utils/navigationtreeview.h
+++ b/src/libs/utils/navigationtreeview.h
@@ -14,6 +14,7 @@ class QTCREATOR_UTILS_EXPORT NavigationTreeView : public TreeView
 public:
     explicit NavigationTreeView(QWidget *parent = nullptr);
     void scrollTo(const QModelIndex &index, ScrollHint hint = EnsureVisible) override;
+    QModelIndex moveCursor(CursorAction cursorAction, Qt::KeyboardModifiers modifiers) override;
 
 protected:
     void focusInEvent(QFocusEvent *event) override;