Debugger: Improve keyboard navigation in locals view

Expanding items in the locals view results in replacing the original
tree item with a newly created one. This ultimately resets the selection
and the current item of the view, which in turn makes it cumbersome to
navigate by keyboard.

Save a list of selected inames and the iname of the current index when
requesting the update and try to reselect them after the update
finished.

Fixes: QTCREATORBUG-27569
Change-Id: I9d8f51631e4ee490e19307877cbef44798506016
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/debugger/watchhandler.cpp

@@ -469,7 +469,6 @@ public:
 
     QSet<QString> m_expandedINames;
     QHash<QString, int> m_maxArrayCount;
-    QTimer m_requestUpdateTimer;
     QTimer m_localsWindowsTimer;
 
     QHash<QString, TypeInfo> m_reportedTypeInfo;
@@ -513,10 +512,6 @@ WatchModel::WatchModel(WatchHandler *handler, DebuggerEngine *engine)
     root->appendChild(m_tooltipRoot);
     setRootItem(root);
 
-    m_requestUpdateTimer.setSingleShot(true);
-    connect(&m_requestUpdateTimer, &QTimer::timeout,
-        this, &WatchModel::updateStarted);
-
     m_localsWindowsTimer.setSingleShot(true);
     m_localsWindowsTimer.setInterval(50);
     connect(&m_localsWindowsTimer, &QTimer::timeout, this, [this] {
@@ -2310,7 +2305,7 @@ void WatchHandler::notifyUpdateStarted(const UpdateParameters &updateParameters)
         }
     }
 
-    m_model->m_requestUpdateTimer.start(80);
+    emit m_model->updateStarted();
     m_model->m_contentsValid = false;
     updateLocalsWindow();
 }
@@ -2350,7 +2345,6 @@ void WatchHandler::notifyUpdateFinished()
     m_model->m_contentsValid = true;
     updateLocalsWindow();
     m_model->reexpandItems();
-    m_model->m_requestUpdateTimer.stop();
     emit m_model->updateFinished();
 }
 

src/plugins/debugger/watchwindow.cpp

@@ -8,6 +8,7 @@
 #include "debuggertr.h"
 #include "watchhandler.h"
 
+#include <utils/algorithm.h>
 #include <utils/aspects.h>
 #include <utils/qtcassert.h>
 
@@ -29,6 +30,10 @@ WatchTreeView::WatchTreeView(WatchType type)
     setAcceptDrops(true);
     setDropIndicatorShown(true);
 
+    m_progressDelayTimer.setSingleShot(true);
+    m_progressDelayTimer.setInterval(80);
+    connect(&m_progressDelayTimer, &QTimer::timeout, this, &WatchTreeView::showProgressIndicator);
+
     connect(this, &QTreeView::expanded, this, &WatchTreeView::expandNode);
     connect(this, &QTreeView::collapsed, this, &WatchTreeView::collapseNode);
 
@@ -71,12 +76,10 @@ void WatchTreeView::setModel(QAbstractItemModel *model)
             this, &QAbstractItemView::setCurrentIndex);
     connect(watchModel, &WatchModelBase::itemIsExpanded,
             this, &WatchTreeView::handleItemIsExpanded);
-    if (m_type == LocalsType) {
     connect(watchModel, &WatchModelBase::updateStarted,
-                this, &WatchTreeView::showProgressIndicator);
+            this, &WatchTreeView::handleUpdateStarted);
     connect(watchModel, &WatchModelBase::updateFinished,
-                this, &WatchTreeView::hideProgressIndicator);
-    }
+            this, &WatchTreeView::handleUpdateFinished);
 
     updateTimeColumn();
 }
@@ -95,6 +98,39 @@ void WatchTreeView::handleItemIsExpanded(const QModelIndex &idx)
         expand(idx);
 }
 
+void WatchTreeView::handleUpdateStarted()
+{
+    m_selectedInames = Utils::transform(selectedIndexes(), [this](const QModelIndex &idx) {
+        return model()->data(idx, LocalsINameRole).toString();
+    });
+    m_currentIname = currentIndex().data(LocalsINameRole).toString();
+    if (m_type == LocalsType)
+        m_progressDelayTimer.start();
+}
+
+void WatchTreeView::handleUpdateFinished()
+{
+    m_progressDelayTimer.stop();
+    if (m_type == LocalsType)
+        hideProgressIndicator();
+
+    auto watchModel = qobject_cast<WatchModelBase *>(model());
+    QTC_ASSERT(watchModel, return);
+    QItemSelection selection;
+    QModelIndex currentIndex;
+    watchModel->forAllItems([&](Utils::TreeItem *item) {
+        const QModelIndex index = item->index();
+        const QString iName = index.data(LocalsINameRole).toString();
+        if (m_selectedInames.contains(iName))
+            selection.append(QItemSelectionRange(index));
+        if (iName == m_currentIname)
+            currentIndex = index;
+    });
+    selectionModel()->select(selection, QItemSelectionModel::Select);
+    if (currentIndex.isValid())
+        setCurrentIndex(currentIndex);
+}
+
 void WatchTreeView::reexpand(QTreeView *view, const QModelIndex &idx)
 {
     if (idx.data(LocalsExpandedRole).toBool()) {

src/plugins/debugger/watchwindow.h

@@ -5,6 +5,8 @@
 
 #include <utils/basetreeview.h>
 
+#include <QTimer>
+
 namespace Debugger {
 namespace Internal {
 
@@ -26,6 +28,8 @@ public:
     void watchExpression(const QString &exp);
     void watchExpression(const QString &exp, const QString &name);
     void handleItemIsExpanded(const QModelIndex &idx);
+    void handleUpdateStarted();
+    void handleUpdateFinished();
 
 signals:
     void currentIndexChanged(const QModelIndex &currentIndex);
@@ -42,6 +46,9 @@ private:
 
     WatchType m_type;
     int m_sliderPosition = 0;
+    QStringList m_selectedInames;
+    QString m_currentIname;
+    QTimer m_progressDelayTimer;
 };
 
 } // namespace Internal