Remove usages of deprecated APIs of QDesktopWidget

- Replaced the usages of the following deprecated APIs:
  * QDesktopWidget::screenCount() -> QGuiApplication::screens().size()
  * QDesktopWidget::screenGeometry(int) -> QGuiApplication::screens().at()
  * QDesktopWidget::screenNumber(QPoint) -> QGuiApplication::screenAt(QPoint)

- Added notes for the QWidget *QDesktopWidget::screen(int), which
currently has no replacement.

- Fixed the tests to build conditionally, only when these APIs are
enabled.

Task-number: QTBUG-76491
Change-Id: I2fdec96d0a6a4fc782c53549b05a5556412b8305
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

3 files changed, 9 insertions, 7 deletions

diff --git a/tests/manual/qcursor/qcursorhighdpi/main.cpp b/tests/manual/qcursor/qcursorhighdpi/main.cpp
index 3b18bff91c..017f41eccd 100644
--- a/tests/manual/qcursor/qcursorhighdpi/main.cpp
+++ b/tests/manual/qcursor/qcursorhighdpi/main.cpp
@@ -356,15 +356,12 @@ int main(int argc, char *argv[])
     QApplication app(argc, argv);
 
     MainWindowPtrList windows;
-
-    QDesktopWidget *desktopWidget = app.desktop();
-
     const int lastScreen = arguments.contains("-p")
         ? 0  // Primary screen only
-        : desktopWidget->screenCount() - 1; // All screens
+        : QGuiApplication::screens().size() - 1; // All screens
     for (int s = lastScreen; s >= 0; --s) {
-        MainWindowPtr window(new MainWindow(desktopWidget->screen(s)));
-        const QPoint pos = desktopWidget->screenGeometry(s).center() - QPoint(200, 100);
+        MainWindowPtr window(new MainWindow());
+        const QPoint pos = QGuiApplication::screens().at(s)->geometry().center() - QPoint(200, 100);
         window->move(pos);
         windows.append(window);
         window->show();
diff --git a/tests/manual/qdesktopwidget/main.cpp b/tests/manual/qdesktopwidget/main.cpp
index f4c82c5f72..978dc62b0e 100644
--- a/tests/manual/qdesktopwidget/main.cpp
+++ b/tests/manual/qdesktopwidget/main.cpp
@@ -34,6 +34,7 @@
 
 class DesktopView : public QGraphicsView
 {
+#if QT_DEPRECATED_SINCE(5, 11)
     Q_OBJECT
 public:
     DesktopView()
@@ -195,6 +196,7 @@ private:
     QGraphicsScene *scene;
     QGraphicsRectItem *that;
     QPoint thatRoot;
+#endif
 };
 
 #include "main.moc"
diff --git a/tests/manual/qscreen/main.cpp b/tests/manual/qscreen/main.cpp
index 6fba872b12..0728d66bf9 100644
--- a/tests/manual/qscreen/main.cpp
+++ b/tests/manual/qscreen/main.cpp
@@ -61,8 +61,10 @@ public:
                 QLatin1String("Left-click to test QGuiApplication::topLevelAt(click pos)\nRight-click to ungrab\n") :
                 QLatin1String("Left-click to grab mouse\n");
         if (!m_cursorPos.isNull()) {
+            const auto screen = QGuiApplication::screenAt(m_cursorPos);
+            const auto screenNum = screen ? QGuiApplication::screens().indexOf(screen) : 0;
             txt += QString(QLatin1String("Current mouse position: %1, %2 on screen %3\n"))
-                    .arg(m_cursorPos.x()).arg(m_cursorPos.y()).arg(QApplication::desktop()->screenNumber(m_cursorPos));
+                    .arg(m_cursorPos.x()).arg(m_cursorPos.y()).arg(screenNum);
             if (QGuiApplication::mouseButtons() & Qt::LeftButton) {
                 QWindow *win = QGuiApplication::topLevelAt(m_cursorPos);
                 txt += QString(QLatin1String("Top-level window found? %1\n"))
@@ -234,6 +236,7 @@ void screenAdded(QScreen* screen)
     QList<QScreen *> screens = QGuiApplication::screens();
     int screenNumber = screens.indexOf(screen);
     Q_ASSERT(screenNumber >= 0);
+    // ### Qt 6: Find a replacement for QDesktopWidget::screen()
     w->setParent(qApp->desktop()->screen(screenNumber));
 
     w->show();