Add clearButton-property to QLineEdit.

Based on addAction-API.

Change-Id: Ie6c3d2d728b23a85cdd80428c92ee8208ae0a65c
Done-with: Kevin.Ottens@kdab.com
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@digia.com>

src/widgets/widgets/qlineedit.cpp

@@ -475,6 +475,42 @@ QAction *QLineEdit::addAction(const QIcon &icon, ActionPosition position)
     return result;
 }
 
+/*!
+    \property QLineEdit::clearButtonEnabled
+    \brief Whether the line edit displays a clear button when it is not empty.
+
+    If enabled, the line edit displays a trailing \e clear button when it contains
+    some text, otherwise the line edit does not show a clear button (the
+    default).
+
+    \sa addAction(), removeAction()
+    \since 5.2
+*/
+
+static const char clearButtonActionNameC[] = "_q_qlineeditclearaction";
+
+void QLineEdit::setClearButtonEnabled(bool enable)
+{
+    Q_D(QLineEdit);
+    if (enable == isClearButtonEnabled())
+        return;
+    if (enable) {
+        QAction *clearAction = new QAction(d->clearButtonIcon(), QString(), this);
+        clearAction->setObjectName(QLatin1String(clearButtonActionNameC));
+        d->addAction(clearAction, 0, QLineEdit::TrailingPosition, QLineEditPrivate::SideWidgetClearButton | QLineEditPrivate::SideWidgetFadeInWithText);
+    } else {
+        QAction *clearAction = findChild<QAction *>(QLatin1String(clearButtonActionNameC));
+        Q_ASSERT(clearAction);
+        removeAction(clearAction);
+        delete clearAction;
+    }
+}
+
+bool QLineEdit::isClearButtonEnabled() const
+{
+    return findChild<QAction *>(QLatin1String(clearButtonActionNameC));
+}
+
 void QLineEdit::setFrame(bool enable)
 {
     Q_D(QLineEdit);
@@ -2143,6 +2179,9 @@ void QLineEdit::changeEvent(QEvent *ev)
         update();
         break;
     case QEvent::LayoutDirectionChange:
+        foreach (const QLineEditPrivate::SideWidgetEntry &e, d->trailingSideWidgets) // Refresh icon to show arrow in right direction.
+            if (e.flags & QLineEditPrivate::SideWidgetClearButton)
+                static_cast<QLineEditIconButton *>(e.widget)->setIcon(d->clearButtonIcon());
         d->positionSideWidgets();
         break;
     default:

src/widgets/widgets/qlineedit.h

@@ -85,6 +85,7 @@ class Q_WIDGETS_EXPORT QLineEdit : public QWidget
     Q_PROPERTY(bool acceptableInput READ hasAcceptableInput)
     Q_PROPERTY(QString placeholderText READ placeholderText WRITE setPlaceholderText)
     Q_PROPERTY(Qt::CursorMoveStyle cursorMoveStyle READ cursorMoveStyle WRITE setCursorMoveStyle)
+    Q_PROPERTY(bool clearButtonEnabled READ isClearButtonEnabled WRITE setClearButtonEnabled)
 public:
     enum ActionPosition {
         LeadingPosition,
@@ -108,6 +109,9 @@ public:
     void setFrame(bool);
     bool hasFrame() const;
 
+    void setClearButtonEnabled(bool enable);
+    bool isClearButtonEnabled() const;
+
     enum EchoMode { Normal, NoEcho, Password, PasswordEchoOnEdit };
     EchoMode echoMode() const;
     void setEchoMode(EchoMode);

src/widgets/widgets/qlineedit_p.cpp

@@ -368,6 +368,14 @@ QSize QLineEditPrivate::iconSize() const
     return m_iconSize;
 }
 
+QIcon QLineEditPrivate::clearButtonIcon() const
+{
+    Q_Q(const QLineEdit);
+    QStyleOptionFrameV2 styleOption;
+    q->initStyleOption(&styleOption);
+    return QIcon(q->style()->standardPixmap(QStyle::SP_LineEditClearButton, &styleOption, q));
+}
+
 void QLineEditPrivate::positionSideWidgets()
 {
     Q_Q(QLineEdit);
@@ -417,6 +425,8 @@ QWidget *QLineEditPrivate::addAction(QAction *newAction, QAction *before, QLineE
         QLineEditIconButton *toolButton = new QLineEditIconButton(q);
         toolButton->setIcon(newAction->icon());
         toolButton->setOpacity(lastTextSize > 0 || !(flags & SideWidgetFadeInWithText) ? 1 : 0);
+        if (flags & SideWidgetClearButton)
+            QObject::connect(toolButton, SIGNAL(clicked()), q, SLOT(clear()));
         toolButton->setDefaultAction(newAction);
         w = toolButton;
     }

src/widgets/widgets/qlineedit_p.h

@@ -101,7 +101,8 @@ class Q_AUTOTEST_EXPORT QLineEditPrivate : public QWidgetPrivate
 public:
     enum SideWidgetFlag {
         SideWidgetFadeInWithText = 0x1,
-        SideWidgetCreatedByWidgetAction = 0x2
+        SideWidgetCreatedByWidgetAction = 0x2,
+        SideWidgetClearButton = 0x4
     };
 
     struct SideWidgetEntry {
@@ -197,6 +198,7 @@ public:
     QWidget *addAction(QAction *newAction, QAction *before, QLineEdit::ActionPosition, int flags = 0);
     void removeAction(const QActionEvent *e);
     QSize iconSize() const;
+    QIcon clearButtonIcon() const;
     void positionSideWidgets();
     inline bool hasSideWidgets() const { return !leadingSideWidgets.isEmpty() || !trailingSideWidgets.isEmpty(); }
     inline const SideWidgetEntryList &leftSideWidgetList() const

tests/auto/widgets/widgets/qlineedit/tst_qlineedit.cpp

@@ -297,6 +297,7 @@ private slots:
     void undoRedoAndEchoModes_data();
     void undoRedoAndEchoModes();
 
+    void clearButton();
     void sideWidgets();
 
 protected slots:
@@ -4057,6 +4058,47 @@ void tst_QLineEdit::undoRedoAndEchoModes()
     QCOMPARE(testWidget->text(), expected.at(2));
 }
 
+void tst_QLineEdit::clearButton()
+{
+    // Construct a listview with a stringlist model and filter model.
+    QWidget testWidget;
+    QVBoxLayout *l = new QVBoxLayout(&testWidget);
+    QLineEdit *filterLineEdit = new QLineEdit(&testWidget);
+    l->addWidget(filterLineEdit);
+    QListView *listView = new QListView(&testWidget);
+    QStringListModel *model = new QStringListModel(QStringList() << QStringLiteral("aa") << QStringLiteral("ab") << QStringLiteral("cc"), listView);
+    QSortFilterProxyModel *filterModel = new QSortFilterProxyModel(listView);
+    filterModel->setSourceModel(model);
+    connect(filterLineEdit, SIGNAL(textChanged(QString)), filterModel, SLOT(setFilterFixedString(QString)));
+    listView->setModel(filterModel);
+    l->addWidget(listView);
+    testWidget.move(300, 300);
+    testWidget.show();
+    qApp->setActiveWindow(&testWidget);
+    QVERIFY(QTest::qWaitForWindowActive(&testWidget));
+    // Flip the clear button on,off, trying to detect crashes.
+    filterLineEdit->setClearButtonEnabled(true);
+    QVERIFY(filterLineEdit->isClearButtonEnabled());
+    filterLineEdit->setClearButtonEnabled(true);
+    QVERIFY(filterLineEdit->isClearButtonEnabled());
+    filterLineEdit->setClearButtonEnabled(false);
+    QVERIFY(!filterLineEdit->isClearButtonEnabled());
+    filterLineEdit->setClearButtonEnabled(false);
+    QVERIFY(!filterLineEdit->isClearButtonEnabled());
+    filterLineEdit->setClearButtonEnabled(true);
+    QVERIFY(filterLineEdit->isClearButtonEnabled());
+    // Emulate filtering
+    QToolButton *clearButton = filterLineEdit->findChild<QToolButton *>();
+    QVERIFY(clearButton);
+    QCOMPARE(filterModel->rowCount(), 3);
+    QTest::keyClick(filterLineEdit, 'a');
+    QTRY_COMPARE(filterModel->rowCount(), 2); // matches 'aa', 'ab'
+    QTest::keyClick(filterLineEdit, 'b');
+    QTRY_COMPARE(filterModel->rowCount(), 1); // matches 'ab'
+    QTest::mouseClick(clearButton, Qt::LeftButton, 0, QRect(QPoint(0, 0), clearButton->size()).center());
+    QTRY_COMPARE(filterModel->rowCount(), 3);
+}
+
 void tst_QLineEdit::sideWidgets()
 {
     QWidget testWidget;