QItemDelegate: let QTextEdit and QPlainTextEdit receive tab keypresses

We already let enter/return key presses to reach text edits instead
of closing the editor. Do the same for tab/backtabs.

[ChangeLog][QtWidgets][Important behavior changes] QItemDelegate will
now not close a QTextEdit/QPlainTextEdit editor when the tab key
is pressed; instead, the key will reach the editor.

Task-number: QTBUG-3305
Change-Id: Ife9e6fdc5678535c596d1068770b0963134d8d5a
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>
Reviewed-by: Thorbjørn Lindeijer <bjorn@lindeijer.nl>
Reviewed-by: Thorbjørn Lund Martsum <tmartsum@gmail.com>

src/widgets/itemviews/qabstractitemdelegate.cpp

@@ -420,6 +420,29 @@ QAbstractItemDelegatePrivate::QAbstractItemDelegatePrivate()
 {
 }
 
+static bool editorHandlesKeyEvent(QWidget *editor, const QKeyEvent *event)
+{
+#ifndef QT_NO_TEXTEDIT
+    // do not filter enter / return / tab / backtab for QTextEdit or QPlainTextEdit
+    if (qobject_cast<QTextEdit *>(editor) || qobject_cast<QPlainTextEdit *>(editor)) {
+        switch (event->key()) {
+        case Qt::Key_Tab:
+        case Qt::Key_Backtab:
+        case Qt::Key_Enter:
+        case Qt::Key_Return:
+            return true;
+
+        default:
+            break;
+        }
+    }
+#endif // QT_NO_TEXTEDIT
+
+    Q_UNUSED(editor);
+    Q_UNUSED(event);
+    return false;
+}
+
 bool QAbstractItemDelegatePrivate::editorEventFilter(QObject *object, QEvent *event)
 {
     Q_Q(QAbstractItemDelegate);
@@ -428,7 +451,11 @@ bool QAbstractItemDelegatePrivate::editorEventFilter(QObject *object, QEvent *ev
     if (!editor)
         return false;
     if (event->type() == QEvent::KeyPress) {
-        switch (static_cast<QKeyEvent *>(event)->key()) {
+        QKeyEvent *keyEvent = static_cast<QKeyEvent *>(event);
+        if (editorHandlesKeyEvent(editor, keyEvent))
+            return false;
+
+        switch (keyEvent->key()) {
         case Qt::Key_Tab:
             if (tryFixup(editor)) {
                 emit q->commitData(editor);
@@ -443,10 +470,6 @@ bool QAbstractItemDelegatePrivate::editorEventFilter(QObject *object, QEvent *ev
             return true;
         case Qt::Key_Enter:
         case Qt::Key_Return:
-#ifndef QT_NO_TEXTEDIT
-            if (qobject_cast<QTextEdit *>(editor) || qobject_cast<QPlainTextEdit *>(editor))
-                return false; // don't filter enter key events for QTextEdit or QPlainTextEdit
-#endif // QT_NO_TEXTEDIT
             // We want the editor to be able to process the key press
             // before committing the data (e.g. so it can do
             // validation/fixup of the input).

tests/auto/widgets/itemviews/qdatawidgetmapper/tst_qdatawidgetmapper.cpp

@@ -34,13 +34,18 @@
 #include <QStandardItemModel>
 #include <QLineEdit>
 #include <QComboBox>
+#include <QTextEdit>
+#include <QVBoxLayout>
 #include <QTest>
 #include <QSignalSpy>
+#include <QMetaType>
 
 class tst_QDataWidgetMapper: public QObject
 {
     Q_OBJECT
 private slots:
+    void initTestCase();
+
     void setModel();
     void navigate();
     void addMapping();
@@ -50,8 +55,12 @@ private slots:
     void mappedWidgetAt();
 
     void comboBox();
+
+    void textEditDoesntChangeFocusOnTab_qtbug3305();
 };
 
+Q_DECLARE_METATYPE(QAbstractItemDelegate::EndEditHint)
+
 static QStandardItemModel *testModel(QObject *parent = 0)
 {
     QStandardItemModel *model = new QStandardItemModel(10, 10, parent);
@@ -64,6 +73,11 @@ static QStandardItemModel *testModel(QObject *parent = 0)
     return model;
 }
 
+void tst_QDataWidgetMapper::initTestCase()
+{
+    qRegisterMetaType<QAbstractItemDelegate::EndEditHint>();
+}
+
 void tst_QDataWidgetMapper::setModel()
 {
     QDataWidgetMapper mapper;
@@ -403,5 +417,63 @@ void tst_QDataWidgetMapper::mappedWidgetAt()
     QCOMPARE(mapper.mappedWidgetAt(4242), static_cast<QWidget *>(&lineEdit2));
 }
 
+void tst_QDataWidgetMapper::textEditDoesntChangeFocusOnTab_qtbug3305()
+{
+    QDataWidgetMapper mapper;
+    QAbstractItemModel *model = testModel(&mapper);
+    mapper.setModel(model);
+
+    QSignalSpy closeEditorSpy(mapper.itemDelegate(), SIGNAL(closeEditor(QWidget*,QAbstractItemDelegate::EndEditHint)));
+    QVERIFY(closeEditorSpy.isValid());
+
+    QWidget container;
+    container.setLayout(new QVBoxLayout);
+
+    QLineEdit *lineEdit = new QLineEdit;
+    mapper.addMapping(lineEdit, 0);
+    container.layout()->addWidget(lineEdit);
+
+    QTextEdit *textEdit = new QTextEdit;
+    mapper.addMapping(textEdit, 1);
+    container.layout()->addWidget(textEdit);
+
+    lineEdit->setFocus();
+
+    container.show();
+
+    QApplication::setActiveWindow(&container);
+    QVERIFY(QTest::qWaitForWindowActive(&container));
+
+    int closeEditorSpyCount = 0;
+    const QString textEditContents = textEdit->toPlainText();
+
+    QCOMPARE(closeEditorSpy.count(), closeEditorSpyCount);
+    QVERIFY(lineEdit->hasFocus());
+    QVERIFY(!textEdit->hasFocus());
+
+    // this will generate a closeEditor for the tab key, and another for the focus out
+    QTest::keyClick(QApplication::focusWidget(), Qt::Key_Tab);
+    closeEditorSpyCount += 2;
+    QTRY_COMPARE(closeEditorSpy.count(), closeEditorSpyCount);
+
+    QTRY_VERIFY(textEdit->hasFocus());
+    QVERIFY(!lineEdit->hasFocus());
+
+    // now that the text edit is focused, a tab keypress will insert a tab, not change focus
+    QTest::keyClick(QApplication::focusWidget(), Qt::Key_Tab);
+    QTRY_COMPARE(closeEditorSpy.count(), closeEditorSpyCount);
+
+    QVERIFY(!lineEdit->hasFocus());
+    QVERIFY(textEdit->hasFocus());
+    QCOMPARE(textEdit->toPlainText(), QLatin1Char('\t') + textEditContents);
+
+    // now give focus back to the line edit and check closeEditor gets emitted
+    lineEdit->setFocus();
+    QTRY_VERIFY(lineEdit->hasFocus());
+    QVERIFY(!textEdit->hasFocus());
+    ++closeEditorSpyCount;
+    QCOMPARE(closeEditorSpy.count(), closeEditorSpyCount);
+}
+
 QTEST_MAIN(tst_QDataWidgetMapper)
 #include "tst_qdatawidgetmapper.moc"

tests/auto/widgets/itemviews/qitemdelegate/tst_qitemdelegate.cpp

@@ -1250,11 +1250,19 @@ void tst_QItemDelegate::enterKey_data()
     QTest::addColumn<bool>("expectedFocus");
 
     QTest::newRow("lineedit enter") << LineEdit << int(Qt::Key_Enter) << false;
+    QTest::newRow("lineedit return") << LineEdit << int(Qt::Key_Return) << false;
+    QTest::newRow("lineedit tab") << LineEdit << int(Qt::Key_Tab) << false;
+    QTest::newRow("lineedit backtab") << LineEdit << int(Qt::Key_Backtab) << false;
+
     QTest::newRow("textedit enter") << TextEdit << int(Qt::Key_Enter) << true;
+    QTest::newRow("textedit return") << TextEdit << int(Qt::Key_Return) << true;
+    QTest::newRow("textedit tab") << TextEdit << int(Qt::Key_Tab) << true;
+    QTest::newRow("textedit backtab") << TextEdit << int(Qt::Key_Backtab) << false;
+
     QTest::newRow("plaintextedit enter") << PlainTextEdit << int(Qt::Key_Enter) << true;
     QTest::newRow("plaintextedit return") << PlainTextEdit << int(Qt::Key_Return) << true;
-    QTest::newRow("plaintextedit tab") << PlainTextEdit << int(Qt::Key_Tab) << false;
-    QTest::newRow("lineedit tab") << LineEdit << int(Qt::Key_Tab) << false;
+    QTest::newRow("plaintextedit tab") << PlainTextEdit << int(Qt::Key_Tab) << true;
+    QTest::newRow("plaintextedit backtab") << PlainTextEdit << int(Qt::Key_Backtab) << false;
 }
 
 void tst_QItemDelegate::enterKey()
@@ -1312,10 +1320,11 @@ void tst_QItemDelegate::enterKey()
     QTest::keyClick(editor, Qt::Key(key));
     QApplication::processEvents();
 
-    // The line edit has already been destroyed, so avoid that case.
-    if (widget == TextEdit || widget == PlainTextEdit) {
+    if (expectedFocus) {
         QVERIFY(!editor.isNull());
-        QCOMPARE(editor && editor->hasFocus(), expectedFocus);
+        QVERIFY(editor->hasFocus());
+    } else {
+        QTRY_VERIFY(editor.isNull()); // editor deletion happens via deleteLater
     }
 }