Update Content Manipulation example code

- Use the new signals and slots syntax, QStringLiteral, lambdas and nullptr.
- Use tr consistently for user-visible text.
- Use unprefixed CSS transform properties.
- Remove the "; undefined" workaround for runJavaScript calls, which is supposed
  to prevent a "possible recursion loop and crash" due to QVariant conversion.
  However, since no callback is passed to the method, no such conversion is
  taking place nowadays.

Task-number: QTBUG-60655
Change-Id: Iad9131a17e488bf5e6b1905483be33b562dbfc62
Reviewed-by: Michal Klocek <michal.klocek@qt.io>
Reviewed-by: Viktor Engelmann <viktor.engelmann@qt.io>

2 files changed, 26 insertions, 44 deletions

diff --git a/examples/webenginewidgets/contentmanipulation/doc/src/contentmanipulation.qdoc b/examples/webenginewidgets/contentmanipulation/doc/src/contentmanipulation.qdoc
index 685c20abc..66a1252dc 100644
--- a/examples/webenginewidgets/contentmanipulation/doc/src/contentmanipulation.qdoc
+++ b/examples/webenginewidgets/contentmanipulation/doc/src/contentmanipulation.qdoc
@@ -74,7 +74,7 @@
     The second part of the constructor creates a QWebEngineView and connects
     slots to the view's signals:
 
-    \printuntil SLOT(finishLoading
+    \printuntil MainWindow::finishLoading
 
     Furthermore, we create a QLineEdit as the browser's address bar. We then set the vertical
     QSizePolicy to fill the available area in the browser at all times. We add the
@@ -136,10 +136,6 @@
     \printuntil }
     \printuntil }
 
-    We append \c undefined after the jQuery call to prevent a possible recursion loop
-    and crash caused by the way the elements returned by the each iterator elements
-    reference each other, which causes problems upon converting them to QVariant.
-
     The \c rotateImages() function rotates the images on the current
     web page. This JavaScript code relies on CSS transforms. It
     looks up all \e {img} elements and rotates the images 180 degrees
diff --git a/examples/webenginewidgets/contentmanipulation/mainwindow.cpp b/examples/webenginewidgets/contentmanipulation/mainwindow.cpp
index 74d647c69..154a37747 100644
--- a/examples/webenginewidgets/contentmanipulation/mainwindow.cpp
+++ b/examples/webenginewidgets/contentmanipulation/mainwindow.cpp
@@ -52,22 +52,6 @@
 #include <QtWebEngineWidgets>
 #include "mainwindow.h"
 
-template<typename Arg, typename R, typename C>
-struct InvokeWrapper {
-    R *receiver;
-    void (C::*memberFun)(Arg);
-    void operator()(Arg result) {
-        (receiver->*memberFun)(result);
-    }
-};
-
-template<typename Arg, typename R, typename C>
-InvokeWrapper<Arg, R, C> invoke(R *receiver, void (C::*memberFun)(Arg))
-{
-    InvokeWrapper<Arg, R, C> wrapper = {receiver, memberFun};
-    return wrapper;
-}
-
 MainWindow::MainWindow(const QUrl& url)
 {
     setAttribute(Qt::WA_DeleteOnClose, true);
@@ -82,14 +66,14 @@ MainWindow::MainWindow(const QUrl& url)
 
     view = new QWebEngineView(this);
     view->load(url);
-    connect(view, SIGNAL(loadFinished(bool)), SLOT(adjustLocation()));
-    connect(view, SIGNAL(titleChanged(QString)), SLOT(adjustTitle()));
-    connect(view, SIGNAL(loadProgress(int)), SLOT(setProgress(int)));
-    connect(view, SIGNAL(loadFinished(bool)), SLOT(finishLoading(bool)));
+    connect(view, &QWebEngineView::loadFinished, this, &MainWindow::adjustLocation);
+    connect(view, &QWebEngineView::titleChanged, this, &MainWindow::adjustTitle);
+    connect(view, &QWebEngineView::loadProgress, this, &MainWindow::setProgress);
+    connect(view, &QWebEngineView::loadFinished, this, &MainWindow::finishLoading);
 
     locationEdit = new QLineEdit(this);
     locationEdit->setSizePolicy(QSizePolicy::Expanding, locationEdit->sizePolicy().verticalPolicy());
-    connect(locationEdit, SIGNAL(returnPressed()), SLOT(changeLocation()));
+    connect(locationEdit, &QLineEdit::returnPressed, this, &MainWindow::changeLocation);
 
     QToolBar *toolBar = addToolBar(tr("Navigation"));
     toolBar->addAction(view->pageAction(QWebEnginePage::Back));
@@ -99,38 +83,40 @@ MainWindow::MainWindow(const QUrl& url)
     toolBar->addWidget(locationEdit);
 
     QMenu *viewMenu = menuBar()->addMenu(tr("&View"));
-    QAction* viewSourceAction = new QAction("Page Source", this);
-    connect(viewSourceAction, SIGNAL(triggered()), SLOT(viewSource()));
+    QAction *viewSourceAction = new QAction(tr("Page Source"), this);
+    connect(viewSourceAction, &QAction::triggered, this, &MainWindow::viewSource);
     viewMenu->addAction(viewSourceAction);
 
     QMenu *effectMenu = menuBar()->addMenu(tr("&Effect"));
-    effectMenu->addAction("Highlight all links", this, SLOT(highlightAllLinks()));
+    effectMenu->addAction(tr("Highlight all links"), this, &MainWindow::highlightAllLinks);
 
     rotateAction = new QAction(this);
     rotateAction->setIcon(style()->standardIcon(QStyle::SP_FileDialogDetailedView));
     rotateAction->setCheckable(true);
     rotateAction->setText(tr("Turn images upside down"));
-    connect(rotateAction, SIGNAL(toggled(bool)), this, SLOT(rotateImages(bool)));
+    connect(rotateAction, &QAction::toggled, this, &MainWindow::rotateImages);
     effectMenu->addAction(rotateAction);
 
     QMenu *toolsMenu = menuBar()->addMenu(tr("&Tools"));
-    toolsMenu->addAction(tr("Remove GIF images"), this, SLOT(removeGifImages()));
-    toolsMenu->addAction(tr("Remove all inline frames"), this, SLOT(removeInlineFrames()));
-    toolsMenu->addAction(tr("Remove all object elements"), this, SLOT(removeObjectElements()));
-    toolsMenu->addAction(tr("Remove all embedded elements"), this, SLOT(removeEmbeddedElements()));
+    toolsMenu->addAction(tr("Remove GIF images"), this, &MainWindow::removeGifImages);
+    toolsMenu->addAction(tr("Remove all inline frames"), this, &MainWindow::removeInlineFrames);
+    toolsMenu->addAction(tr("Remove all object elements"), this, &MainWindow::removeObjectElements);
+    toolsMenu->addAction(tr("Remove all embedded elements"), this, &MainWindow::removeEmbeddedElements);
 
     setCentralWidget(view);
 }
 
 void MainWindow::viewSource()
 {
-    QTextEdit* textEdit = new QTextEdit(NULL);
+    QTextEdit *textEdit = new QTextEdit(nullptr);
     textEdit->setAttribute(Qt::WA_DeleteOnClose);
     textEdit->adjustSize();
     textEdit->move(this->geometry().center() - textEdit->rect().center());
     textEdit->show();
 
-    view->page()->toHtml(invoke(textEdit, &QTextEdit::setPlainText));
+    view->page()->toHtml([textEdit](const QString &html){
+        textEdit->setPlainText(html);
+    });
 }
 
 void MainWindow::adjustLocation()
@@ -150,7 +136,7 @@ void MainWindow::adjustTitle()
     if (progress <= 0 || progress >= 100)
         setWindowTitle(view->title());
     else
-        setWindowTitle(QString("%1 (%2%)").arg(view->title()).arg(progress));
+        setWindowTitle(QStringLiteral("%1 (%2%)").arg(view->title()).arg(progress));
 }
 
 void MainWindow::setProgress(int p)
@@ -170,7 +156,7 @@ void MainWindow::finishLoading(bool)
 
 void MainWindow::highlightAllLinks()
 {
-    QString code = "qt.jQuery('a').each( function () { qt.jQuery(this).css('background-color', 'yellow') } ); undefined";
+    QString code = QStringLiteral("qt.jQuery('a').each( function () { qt.jQuery(this).css('background-color', 'yellow') } )");
     view->page()->runJavaScript(code);
 }
 
@@ -179,32 +165,32 @@ void MainWindow::rotateImages(bool invert)
     QString code;
 
     if (invert)
-        code = "qt.jQuery('img').each( function () { qt.jQuery(this).css('-webkit-transition', '-webkit-transform 2s'); qt.jQuery(this).css('-webkit-transform', 'rotate(180deg)') } ); undefined";
+        code = QStringLiteral("qt.jQuery('img').each( function () { qt.jQuery(this).css('transition', 'transform 2s'); qt.jQuery(this).css('transform', 'rotate(180deg)') } )");
     else
-        code = "qt.jQuery('img').each( function () { qt.jQuery(this).css('-webkit-transition', '-webkit-transform 2s'); qt.jQuery(this).css('-webkit-transform', 'rotate(0deg)') } ); undefined";
+        code = QStringLiteral("qt.jQuery('img').each( function () { qt.jQuery(this).css('transition', 'transform 2s'); qt.jQuery(this).css('transform', 'rotate(0deg)') } )");
     view->page()->runJavaScript(code);
 }
 
 void MainWindow::removeGifImages()
 {
-    QString code = "qt.jQuery('[src*=gif]').remove()";
+    QString code = QStringLiteral("qt.jQuery('[src*=gif]').remove()");
     view->page()->runJavaScript(code);
 }
 
 void MainWindow::removeInlineFrames()
 {
-    QString code = "qt.jQuery('iframe').remove()";
+    QString code = QStringLiteral("qt.jQuery('iframe').remove()");
     view->page()->runJavaScript(code);
 }
 
 void MainWindow::removeObjectElements()
 {
-    QString code = "qt.jQuery('object').remove()";
+    QString code = QStringLiteral("qt.jQuery('object').remove()");
     view->page()->runJavaScript(code);
 }
 
 void MainWindow::removeEmbeddedElements()
 {
-    QString code = "qt.jQuery('embed').remove()";
+    QString code = QStringLiteral("qt.jQuery('embed').remove()");
     view->page()->runJavaScript(code);
 }