Doc/QtCore: use new signal/slot signature in snippets

Use the new signal/slot syntax in the snippets where possible. Also
change some 0 to nullptr.

Change-Id: Ie3da2721d3cec33704f73f4d39c06a767717b095
Reviewed-by: Sze Howe Koh <szehowe.koh@gmail.com>

src/corelib/doc/snippets/code/src_corelib_kernel_qcoreapplication.cpp

@@ -56,7 +56,7 @@ QApplication::sendEvent(mainWindow, &event);
 
 //! [1]
 QPushButton *quitButton = new QPushButton("Quit");
-connect(quitButton, SIGNAL(clicked()), &app, SLOT(quit()), Qt::QueuedConnection);
+connect(quitButton, &QPushButton::clicked, &app, &QCoreApplication::quit, Qt::QueuedConnection);
 //! [1]
 
 
@@ -79,12 +79,12 @@ Q_COREAPP_STARTUP_FUNCTION(preRoutineMyDebugTool)
 
 
 //! [4]
-static int *global_ptr = 0;
+static int *global_ptr = nullptr;
 
 static void cleanup_ptr()
 {
     delete [] global_ptr;
-    global_ptr = 0;
+    global_ptr = nullptr;
 }
 
 void init_ptr()
@@ -125,9 +125,9 @@ private:
 
 //! [6]
 static inline QString tr(const char *sourceText,
-                         const char *comment = 0);
+                         const char *comment = nullptr);
 static inline QString trUtf8(const char *sourceText,
-                             const char *comment = 0);
+                             const char *comment = nullptr);
 //! [6]
 
 

src/corelib/doc/snippets/code/src_corelib_statemachine_qstatemachine.cpp

@@ -56,7 +56,7 @@ QState *s1 = new QState();
 s1->assignProperty(&button, "text", "Click me");
 
 QFinalState *s2 = new QFinalState();
-s1->addTransition(&button, SIGNAL(clicked()), s2);
+s1->addTransition(&button, &QPushButton::clicked, s2);
 
 machine.addState(s1);
 machine.addState(s2);

src/corelib/doc/snippets/code/src_corelib_thread_qfuturewatcher.cpp

@@ -52,7 +52,7 @@
 // Instantiate the objects and connect to the finished signal.
 MyClass myObject;
 QFutureWatcher<int> watcher;
-connect(&watcher, SIGNAL(finished()), &myObject, SLOT(handleFinished()));
+connect(&watcher, QFutureWatcher<int>::finished, &myObject, &MyClass::handleFinished);
 
 // Start the computation.
 QFuture<int> future = QtConcurrent::run(...);

src/corelib/doc/snippets/code/src_corelib_tools_qtimeline.cpp

@@ -56,10 +56,10 @@ progressBar->setRange(0, 100);
 // Construct a 1-second timeline with a frame range of 0 - 100
 QTimeLine *timeLine = new QTimeLine(1000, this);
 timeLine->setFrameRange(0, 100);
-connect(timeLine, SIGNAL(frameChanged(int)), progressBar, SLOT(setValue(int)));
+connect(timeLine, &QTimeLine::frameChanged, progressBar, &QProgressBar::setValue);
 
 // Clicking the push button will start the progress bar animation
 pushButton = new QPushButton(tr("Start animation"), this);
-connect(pushButton, SIGNAL(clicked()), timeLine, SLOT(start()));
+connect(pushButton, &QPushButton::clicked, timeLine, &QTimeLine::start);
 ...
 //! [0]

src/corelib/doc/snippets/qsignalmapper/buttonwidget.cpp

@@ -48,11 +48,10 @@
 **
 ****************************************************************************/
 
-#include <QtGui>
-#include <QtWidgets>
-
 #include "buttonwidget.h"
 
+#include <QtWidgets>
+
 //! [0]
 ButtonWidget::ButtonWidget(const QStringList &texts, QWidget *parent)
     : QWidget(parent)
@@ -62,15 +61,16 @@ ButtonWidget::ButtonWidget(const QStringList &texts, QWidget *parent)
     QGridLayout *gridLayout = new QGridLayout;
     for (int i = 0; i < texts.size(); ++i) {
         QPushButton *button = new QPushButton(texts[i]);
-        connect(button, SIGNAL(clicked()), signalMapper, SLOT(map()));
+        connect(button, &QPushButton::clicked,
+                signalMapper, &QSignalMapper::map);
 //! [0] //! [1]
         signalMapper->setMapping(button, texts[i]);
         gridLayout->addWidget(button, i / 3, i % 3);
     }
 
-    connect(signalMapper, SIGNAL(mapped(QString)),
+    connect(signalMapper, QOverload<const QString &>::of(&QSignalMapper::mapped),
 //! [1] //! [2]
-            this, SIGNAL(clicked(QString)));
+            this, &ButtonWidget::clicked);
 
     setLayout(gridLayout);
 }
@@ -84,7 +84,7 @@ ButtonWidget::ButtonWidget(const QStringList &texts, QWidget *parent)
     for (int i = 0; i < texts.size(); ++i) {
         QString text = texts[i];
         QPushButton *button = new QPushButton(text);
-        connect(button, &QPushButton::clicked, [=] { clicked(text); });
+        connect(button, &QPushButton::clicked, [this, text] { clicked(text); });
         gridLayout->addWidget(button, i / 3, i % 3);
     }
     setLayout(gridLayout);

src/corelib/doc/snippets/qsignalmapper/buttonwidget.h

@@ -51,7 +51,7 @@
 #ifndef BUTTONWIDGET_H
 #define BUTTONWIDGET_H
 
-#include <qwidget.h>
+#include <QWidget>
 
 class QSignalMapper;
 class QString;
@@ -63,7 +63,7 @@ class ButtonWidget : public QWidget
     Q_OBJECT
 
 public:
-    ButtonWidget(const QStringList &texts, QWidget *parent = 0);
+    ButtonWidget(const QStringList &texts, QWidget *parent = nullptr);
 
 signals:
     void clicked(const QString &text);

src/corelib/doc/snippets/resource-system/mainwindow.cpp

@@ -68,10 +68,10 @@ MainWindow::MainWindow()
 
     readSettings();
 
-    connect(textEdit->document(), SIGNAL(contentsChanged()),
+    connect(textEdit->document(), &QTextEdit::contentsChanged,
-            this, SLOT(documentWasModified()));
+            this, &QAction::documentWasModified);
 
-    setCurrentFile("");
+    setCurrentFile(QString());
     setUnifiedTitleAndToolBarOnMac(true);
 }
 //! [2]
@@ -95,7 +95,7 @@ void MainWindow::newFile()
 {
     if (maybeSave()) {
         textEdit->clear();
-        setCurrentFile("");
+        setCurrentFile(QString());
     }
 }
 //! [6]
@@ -162,31 +162,31 @@ void MainWindow::createActions()
     newAct = new QAction(QIcon(":/images/new.png"), tr("&New"), this);
     newAct->setShortcuts(QKeySequence::New);
     newAct->setStatusTip(tr("Create a new file"));
-    connect(newAct, SIGNAL(triggered()), this, SLOT(newFile()));
+    connect(newAct, &QAction::triggered, this, &MainWindow::newFile);
 
 //! [19]
     openAct = new QAction(QIcon(":/images/open.png"), tr("&Open..."), this);
     openAct->setShortcuts(QKeySequence::Open);
     openAct->setStatusTip(tr("Open an existing file"));
-    connect(openAct, SIGNAL(triggered()), this, SLOT(open()));
+    connect(openAct, &QAction::triggered, this, &MainWindow::open);
 //! [18] //! [19]
 
     saveAct = new QAction(QIcon(":/images/save.png"), tr("&Save"), this);
     saveAct->setShortcuts(QKeySequence::Save);
     saveAct->setStatusTip(tr("Save the document to disk"));
-    connect(saveAct, SIGNAL(triggered()), this, SLOT(save()));
+    connect(saveAct, &QAction::triggered, this, &MainWindow::save);
 
     saveAsAct = new QAction(tr("Save &As..."), this);
     saveAsAct->setShortcuts(QKeySequence::SaveAs);
     saveAsAct->setStatusTip(tr("Save the document under a new name"));
-    connect(saveAsAct, SIGNAL(triggered()), this, SLOT(saveAs()));
+    connect(saveAsAct, &QAction::triggered, this, &MainWindow::saveAs);
 
 //! [20]
     exitAct = new QAction(tr("E&xit"), this);
     exitAct->setShortcuts(QKeySequence::Quit);
 //! [20]
     exitAct->setStatusTip(tr("Exit the application"));
-    connect(exitAct, SIGNAL(triggered()), this, SLOT(close()));
+    connect(exitAct, &QAction::triggered, this, &MainWindow::close);
 
 //! [21]
     cutAct = new QAction(QIcon(":/images/cut.png"), tr("Cu&t"), this);
@@ -194,38 +194,38 @@ void MainWindow::createActions()
     cutAct->setShortcuts(QKeySequence::Cut);
     cutAct->setStatusTip(tr("Cut the current selection's contents to the "
                             "clipboard"));
-    connect(cutAct, SIGNAL(triggered()), textEdit, SLOT(cut()));
+    connect(cutAct, &QAction::triggered, textEdit, &QTextEdit::cut);
 
     copyAct = new QAction(QIcon(":/images/copy.png"), tr("&Copy"), this);
     copyAct->setShortcuts(QKeySequence::Copy);
     copyAct->setStatusTip(tr("Copy the current selection's contents to the "
                              "clipboard"));
-    connect(copyAct, SIGNAL(triggered()), textEdit, SLOT(copy()));
+    connect(copyAct, &QAction::triggered, textEdit, &QTextEdit::copy);
 
     pasteAct = new QAction(QIcon(":/images/paste.png"), tr("&Paste"), this);
     pasteAct->setShortcuts(QKeySequence::Paste);
     pasteAct->setStatusTip(tr("Paste the clipboard's contents into the current "
                               "selection"));
-    connect(pasteAct, SIGNAL(triggered()), textEdit, SLOT(paste()));
+    connect(pasteAct, &QAction::triggered, textEdit, &QTextEdit::paste);
 
     aboutAct = new QAction(tr("&About"), this);
     aboutAct->setStatusTip(tr("Show the application's About box"));
-    connect(aboutAct, SIGNAL(triggered()), this, SLOT(about()));
+    connect(aboutAct, &QAction::triggered, this, &MainWindow::about);
 
 //! [22]
     aboutQtAct = new QAction(tr("About &Qt"), this);
     aboutQtAct->setStatusTip(tr("Show the Qt library's About box"));
-    connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));
+    connect(aboutQtAct, &QAction::triggered, qApp, &QApplication::aboutQt);
 //! [22]
 
 //! [23]
     cutAct->setEnabled(false);
 //! [23] //! [24]
     copyAct->setEnabled(false);
-    connect(textEdit, SIGNAL(copyAvailable(bool)),
+    connect(textEdit, &QTextEdit::copyAvailable,
-            cutAct, SLOT(setEnabled(bool)));
+            cutAct, &QAction::setEnabled);
-    connect(textEdit, SIGNAL(copyAvailable(bool)),
+    connect(textEdit, &QTextEdit::copyAvailable,
-            copyAct, SLOT(setEnabled(bool)));
+            copyAct, &QAction::setEnabled);
 }
 //! [24]
 

src/corelib/doc/snippets/statemachine/main.cpp

@@ -48,13 +48,14 @@
 **
 ****************************************************************************/
 
-#include <QtGui>
+#include <QtWidgets>
 
 int main(int argv, char **args)
 {
     QApplication app(argv, args);
 
     QLabel *label = new QLabel;
+    QPushButton *button = new QPushButton;
 
 //![0]
     QStateMachine machine;
@@ -70,14 +71,14 @@ int main(int argv, char **args)
 //![4]
 
 //![5]
-    QObject::connect(s3, SIGNAL(entered()), button, SLOT(showMaximized()));
+    QObject::connect(s3, &QState::entered, button, &QPushButton:showMaximized);
-    QObject::connect(s3, SIGNAL(exited()), button, SLOT(showMinimized()));
+    QObject::connect(s3, &QState::exited, button, &QPushButton::showMinimized);
 //![5]
 
 //![1]
-    s1->addTransition(button, SIGNAL(clicked()), s2);
+    s1->addTransition(button, &QPushButton::clicked, s2);
-    s2->addTransition(button, SIGNAL(clicked()), s3);
+    s2->addTransition(button, &QPushButton::clicked, s3);
-    s3->addTransition(button, SIGNAL(clicked()), s1);
+    s3->addTransition(button, &QPushButton::clicked, s1);
 //![1]
 
 //![2]

src/corelib/doc/snippets/statemachine/main2.cpp

@@ -48,7 +48,7 @@
 **
 ****************************************************************************/
 
-#include <QtGui>
+#include <QtWidgets>
 
 int main(int argv, char **args)
 {
@@ -66,16 +66,17 @@ int main(int argv, char **args)
 //![0]
 
 //![2]
-    s12->addTransition(quitButton, SIGNAL(clicked()), s12);
+    s12->addTransition(quitButton, &QPushButton::clicked, s12);
 //![2]
 
 //![1]
     QFinalState *s2 = new QFinalState();
-    s1->addTransition(quitButton, SIGNAL(clicked()), s2);
+    s1->addTransition(quitButton, &QPushButton::clicked, s2);
     machine.addState(s2);
     machine.setInitialState(s1);
 
-    QObject::connect(&machine, SIGNAL(finished()), QApplication::instance(), SLOT(quit()));
+    QObject::connect(&machine, &QStateMachine::finished,
+                     QCoreApplication::instance(), &QCoreApplication::quit);
 //![1]
 
   QButton *interruptButton = new QPushButton("Interrupt Button");
@@ -90,11 +91,11 @@ int main(int argv, char **args)
     mbox->addButton(QMessageBox::Ok);
     mbox->setText("Interrupted!");
     mbox->setIcon(QMessageBox::Information);
-    QObject::connect(s3, SIGNAL(entered()), mbox, SLOT(exec()));
+    QObject::connect(s3, &QState::entered, mbox, &QMessageBox::exec);
     s3->addTransition(s1h);
     machine.addState(s3);
 
-    s1->addTransition(interruptButton, SIGNAL(clicked()), s3);
+    s1->addTransition(interruptButton, &QPushButton::clicked, s3);
 //![3]
 
   return app.exec();

src/corelib/doc/snippets/statemachine/main3.cpp

@@ -62,7 +62,7 @@ int main(int argv, char **args)
 //![0]
 
 //![1]
-  s1->addTransition(s1, SIGNAL(finished()), s2);
+  s1->addTransition(s1, &QState::finished, s2);
 //![1]
 
     return app.exec();

src/corelib/doc/snippets/statemachine/main5.cpp

@@ -98,7 +98,7 @@ int main(int argv, char **args)
     s1->assignProperty(button, "geometry", QRectF(0, 0, 50, 50));
     s2->assignProperty(button, "geometry", QRectF(0, 0, 100, 100));
 
-    s1->addTransition(button, SIGNAL(clicked()), s2);
+    s1->addTransition(button, &QPushButton::clicked, s2);
 //![3]
 
   }
@@ -111,7 +111,7 @@ int main(int argv, char **args)
     s1->assignProperty(button, "geometry", QRectF(0, 0, 50, 50));
     s2->assignProperty(button, "geometry", QRectF(0, 0, 100, 100));
 
-    QSignalTransition *transition = s1->addTransition(button, SIGNAL(clicked()), s2);
+    QSignalTransition *transition = s1->addTransition(button, &QPushButton::clicked, s2);
     transition->addAnimation(new QPropertyAnimation(button, "geometry"));
 //![4]
 
@@ -130,9 +130,9 @@ int main(int argv, char **args)
 
     QState *s2 = new QState();
     s2->assignProperty(button, "geometry", QRectF(0, 0, 50, 50));
-    connect(s2, SIGNAL(entered()), messageBox, SLOT(exec()));
+    connect(s2, &QState::entered, messageBox, SLOT(exec()));
 
-    s1->addTransition(button, SIGNAL(clicked()), s2);
+    s1->addTransition(button, &QPushButton::clicked, s2);
 //![5]
   }
 
@@ -151,10 +151,10 @@ int main(int argv, char **args)
     s2->assignProperty(button, "geometry", QRectF(0, 0, 50, 50));
 
     QState *s3 = new QState();
-    connect(s3, SIGNAL(entered()), messageBox, SLOT(exec()));
+    connect(s3, &QState::entered, messageBox, SLOT(exec()));
 
-    s1->addTransition(button, SIGNAL(clicked()), s2);
+    s1->addTransition(button, &QPushButton::clicked, s2);
-    s2->addTransition(s2, SIGNAL(propertiesAssigned()), s3);
+    s2->addTransition(s2, &QState::propertiesAssigned, s3);
 //![6]
 
   }

src/corelib/doc/snippets/timers/analogclock.cpp

@@ -61,7 +61,7 @@ AnalogClock::AnalogClock(QWidget *parent)
 //! [3] //! [4]
     QTimer *timer = new QTimer(this);
 //! [4] //! [5]
-    connect(timer, SIGNAL(timeout()), this, SLOT(update()));
+    connect(timer, &QTimer::timeout, this, QOverload<>::of(&AnalogClock::update));
 //! [5] //! [6]
     timer->start(1000);
 //! [6]

src/corelib/doc/snippets/timers/timers.cpp

@@ -61,13 +61,13 @@ Foo::Foo()
 //! [0]
     QTimer *timer = new QTimer(this);
 //! [0] //! [1]
-    connect(timer, SIGNAL(timeout()), this, SLOT(updateCaption()));
+    connect(timer, &QTimer::timeout, this, &Foo::updateCaption);
 //! [1] //! [2]
     timer->start(1000);
 //! [2]
 
 //! [3]
-    QTimer::singleShot(200, this, SLOT(updateCaption()));
+    QTimer::singleShot(200, this, &Foo::updateCaption);
 //! [3]
 
     {
@@ -75,7 +75,7 @@ Foo::Foo()
 //! [4]
     QTimer *timer = new QTimer(this);
 //! [4] //! [5]
-    connect(timer, SIGNAL(timeout()), this, SLOT(processOneThing()));
+    connect(timer, &QTimer::timeout, this, &Foo::processOneThing);
 //! [5] //! [6]
     timer->start();
 //! [6]

src/corelib/doc/src/animation.qdoc

@@ -356,11 +356,11 @@
         state2->assignProperty(button, "geometry", QRect(250, 250, 100, 30));
 
         QSignalTransition *transition1 = state1->addTransition(button,
-            SIGNAL(clicked()), state2);
+            &QPushButton::clicked, state2);
         transition1->addAnimation(new QPropertyAnimation(button, "geometry"));
 
         QSignalTransition *transition2 = state2->addTransition(button,
-            SIGNAL(clicked()), state1);
+            &QPushButton::clicked, state1);
         transition2->addAnimation(new QPropertyAnimation(button, "geometry"));
 
         machine->start();

src/corelib/doc/src/statemachine.qdoc

@@ -323,12 +323,12 @@
     QState *s1 = new QState(&machine);
 
     QPushButton button;
-    QSignalTransition *trans = new QSignalTransition(&button, SIGNAL(clicked()));
+    QSignalTransition *trans = new QSignalTransition(&button, &QPushButton::clicked);
     s1->addTransition(trans);
 
     QMessageBox msgBox;
     msgBox.setText("The button was clicked; carry on.");
-    QObject::connect(trans, SIGNAL(triggered()), &msgBox, SLOT(exec()));
+    QObject::connect(trans, QSignalTransition::triggered, &msgBox, &QMessageBox::exec);
 
     machine.setInitialState(s1);
   \endcode