Better handle input plugin switches in the KeyboardSelectionListModel

If the current dataSource gets destroyed, make sure to update the
rowCount accordingly, otherwise there might be a lot of QML warnings like
these:

.../style.qml:709:13: Unable to assign [undefined] to QString

In addition also do a boundary check in the data() function to make
sure the data requested from the plugin are really available.

Change-Id: I5ea57b945bc33a309c3b3b18ec029296d5428950
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

2 files changed, 21 insertions, 1 deletions

diff --git a/src/virtualkeyboard/qvirtualkeyboardselectionlistmodel.cpp b/src/virtualkeyboard/qvirtualkeyboardselectionlistmodel.cpp
index d2cbc22e..90b1e7df 100644
--- a/src/virtualkeyboard/qvirtualkeyboardselectionlistmodel.cpp
+++ b/src/virtualkeyboard/qvirtualkeyboardselectionlistmodel.cpp
@@ -170,6 +170,7 @@ void QVirtualKeyboardSelectionListModel::setDataSource(QVirtualKeyboardAbstractI
     if (d->dataSource) {
         disconnect(this, SLOT(selectionListChanged(Type)));
         disconnect(this, SLOT(selectionListActiveItemChanged(Type, int)));
+        disconnect(this, SLOT(dataSourceDestroyed()));
     }
     d->type = type;
     if (d->dataSource) {
@@ -181,6 +182,7 @@ void QVirtualKeyboardSelectionListModel::setDataSource(QVirtualKeyboardAbstractI
     if (d->dataSource) {
         QObject::connect(d->dataSource.data(), &QVirtualKeyboardAbstractInputMethod::selectionListChanged, this, &QVirtualKeyboardSelectionListModel::selectionListChanged);
         QObject::connect(d->dataSource.data(), &QVirtualKeyboardAbstractInputMethod::selectionListActiveItemChanged, this, &QVirtualKeyboardSelectionListModel::selectionListActiveItemChanged);
+        QObject::connect(d->dataSource.data(), &QObject::destroyed, this, &QVirtualKeyboardSelectionListModel::dataSourceDestroyed);
     }
 }
 
@@ -209,7 +211,14 @@ int QVirtualKeyboardSelectionListModel::rowCount(const QModelIndex &parent) cons
 QVariant QVirtualKeyboardSelectionListModel::data(const QModelIndex &index, int role) const
 {
     Q_D(const QVirtualKeyboardSelectionListModel);
-    return d->dataSource ? d->dataSource->selectionListData(d->type, index.row(), static_cast<Role>(role)) : QVariant();
+
+    if (!d->dataSource)
+        return QVariant();
+
+    if (index.row() < 0 || index.row() >= d->rowCount)
+        return QVariant();
+
+    return d->dataSource->selectionListData(d->type, index.row(), static_cast<Role>(role));
 }
 
 /*!
@@ -332,6 +341,16 @@ void QVirtualKeyboardSelectionListModel::selectionListActiveItemChanged(QVirtual
 }
 
 /*!
+    \internal
+*/
+void QVirtualKeyboardSelectionListModel::dataSourceDestroyed()
+{
+    Q_D(QVirtualKeyboardSelectionListModel);
+    selectionListChanged(d->type);
+    selectionListActiveItemChanged(d->type, -1);
+}
+
+/*!
     \qmlsignal void SelectionListModel::activeItemChanged(int index)
 
     This signal is emitted when the active item in the list changes. The
diff --git a/src/virtualkeyboard/qvirtualkeyboardselectionlistmodel.h b/src/virtualkeyboard/qvirtualkeyboardselectionlistmodel.h
index 40d07d7c..c19d9ed1 100644
--- a/src/virtualkeyboard/qvirtualkeyboardselectionlistmodel.h
+++ b/src/virtualkeyboard/qvirtualkeyboardselectionlistmodel.h
@@ -93,6 +93,7 @@ Q_SIGNALS:
 protected Q_SLOTS:
     void selectionListChanged(Type type);
     void selectionListActiveItemChanged(Type type, int index);
+    void dataSourceDestroyed();
 
 private:
     friend class QVirtualKeyboardInputEngine;