macOS: Add dialog helper for native message boxes

The native implementation uses NSAlert, making a best effort to map the
QMessageBox properties to the native dialog, falling back to the cross
platform non-native dialog if the discrepancy is too big.

The initial implementation focuses on the current state of the
native dialog helper "protocol", but there's room for improvement
here, which would allow even more dialog types and properties to
be native.

[ChangeLog][macOS] Message boxes such as QMessageBox now follow
the platform look and feel by using native dialogs if possible.

Change-Id: I4da33f99894194a7b301628cd1fbb44d646ddf18
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

1 files changed, 35 insertions, 0 deletions

diff --git a/tests/auto/widgets/dialogs/qmessagebox/tst_qmessagebox.cpp b/tests/auto/widgets/dialogs/qmessagebox/tst_qmessagebox.cpp
index 495a935255..808cd41b28 100644
--- a/tests/auto/widgets/dialogs/qmessagebox/tst_qmessagebox.cpp
+++ b/tests/auto/widgets/dialogs/qmessagebox/tst_qmessagebox.cpp
@@ -23,6 +23,9 @@ class tst_QMessageBox : public QObject
     Q_OBJECT
 
 private slots:
+    void initTestCase_data();
+    void init();
+
     void sanityTest();
     void defaultButton();
     void escapeButton();
@@ -129,6 +132,22 @@ void ExecCloseHelper::timerEvent(QTimerEvent *te)
     }
 }
 
+void tst_QMessageBox::initTestCase_data()
+{
+    QTest::addColumn<bool>("useNativeDialog");
+    QTest::newRow("widget") << false;
+    if (const QPlatformTheme *theme = QGuiApplicationPrivate::platformTheme()) {
+        if (theme->usePlatformNativeDialog(QPlatformTheme::MessageDialog))
+            QTest::newRow("native") << true;
+    }
+}
+
+void tst_QMessageBox::init()
+{
+    QFETCH_GLOBAL(bool, useNativeDialog);
+    qApp->setAttribute(Qt::AA_DontUseNativeDialogs, !useNativeDialog);
+}
+
 void tst_QMessageBox::cleanup()
 {
     QTRY_VERIFY(QApplication::topLevelWidgets().isEmpty()); // OS X requires TRY
@@ -484,6 +503,10 @@ void tst_QMessageBox::instanceSourceCompat()
 
 void tst_QMessageBox::detailsText()
 {
+    QFETCH_GLOBAL(bool, useNativeDialog);
+    if (useNativeDialog)
+         QSKIP("Native dialogs do not propagate expose events");
+
     QMessageBox box;
     QString text("This is the details text.");
     box.setDetailedText(text);
@@ -497,6 +520,10 @@ void tst_QMessageBox::detailsText()
 
 void tst_QMessageBox::detailsButtonText()
 {
+    QFETCH_GLOBAL(bool, useNativeDialog);
+    if (useNativeDialog)
+         QSKIP("Native dialogs do not propagate expose events");
+
     QMessageBox box;
     box.setDetailedText("bla");
     box.open();
@@ -518,6 +545,10 @@ void tst_QMessageBox::detailsButtonText()
 
 void tst_QMessageBox::expandDetailsWithoutMoving() // QTBUG-32473
 {
+    QFETCH_GLOBAL(bool, useNativeDialog);
+    if (useNativeDialog)
+         QSKIP("Native dialogs do not propagate expose events");
+
     tst_ResizingMessageBox box;
     box.setDetailedText("bla");
     box.show();
@@ -617,6 +648,10 @@ Q_DECLARE_METATYPE(RoleSet);
 
 void tst_QMessageBox::acceptedRejectedSignals()
 {
+    QFETCH_GLOBAL(bool, useNativeDialog);
+    if (useNativeDialog)
+         QSKIP("Native dialogs do not propagate expose events");
+
     QMessageBox messageBox(QMessageBox::Information, "Test window", "Test text");
 
     QFETCH(ButtonsCreator, buttonsCreator);