iOS: add support for custom buttons in native MessageDialog helper

[ChangeLog][QtWidgets][QMessageBox] On Android and iOS it's now possible
to show a QMessageBox with custom buttons as a native dialog.

Task-number: QTBUG-35545
Change-Id: Id3be69e70468f767a43ea5f2ba64f9bac1898423
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

2 files changed, 20 insertions, 1 deletions

diff --git a/src/plugins/platforms/ios/qiosmessagedialog.h b/src/plugins/platforms/ios/qiosmessagedialog.h
index 92a4db8319..913fe0c2e9 100644
--- a/src/plugins/platforms/ios/qiosmessagedialog.h
+++ b/src/plugins/platforms/ios/qiosmessagedialog.h
@@ -63,6 +63,7 @@ private:
     UIAlertController *m_alertController;
     QString messageTextPlain();
     UIAlertAction *createAction(StandardButton button);
+    UIAlertAction *createAction(const QMessageDialogOptions::CustomButton &customButton);
 };
 
 QT_END_NAMESPACE
diff --git a/src/plugins/platforms/ios/qiosmessagedialog.mm b/src/plugins/platforms/ios/qiosmessagedialog.mm
index a7de9b473a..254922701a 100644
--- a/src/plugins/platforms/ios/qiosmessagedialog.mm
+++ b/src/plugins/platforms/ios/qiosmessagedialog.mm
@@ -79,6 +79,18 @@ inline QString QIOSMessageDialog::messageTextPlain()
     return text;
 }
 
+inline UIAlertAction *QIOSMessageDialog::createAction(
+        const QMessageDialogOptions::CustomButton &customButton)
+{
+    const QString label = QPlatformTheme::removeMnemonics(customButton.label);
+    const UIAlertActionStyle style = UIAlertActionStyleDefault;
+
+    return [UIAlertAction actionWithTitle:label.toNSString() style:style handler:^(UIAlertAction *) {
+        hide();
+        emit clicked(static_cast<QPlatformDialogHelper::StandardButton>(customButton.id), customButton.role);
+    }];
+}
+
 inline UIAlertAction *QIOSMessageDialog::createAction(StandardButton button)
 {
     const StandardButton labelButton = button == NoButton ? Ok : button;
@@ -118,12 +130,18 @@ bool QIOSMessageDialog::show(Qt::WindowFlags windowFlags, Qt::WindowModality win
         message:messageTextPlain().toNSString()
         preferredStyle:UIAlertControllerStyleAlert] retain];
 
+    const QVector<QMessageDialogOptions::CustomButton> customButtons = options()->customButtons();
+    for (const QMessageDialogOptions::CustomButton &button : customButtons) {
+        UIAlertAction *act = createAction(button);
+        [m_alertController addAction:act];
+    }
+
     if (StandardButtons buttons = options()->standardButtons()) {
         for (int i = FirstButton; i < LastButton; i<<=1) {
             if (i & buttons)
                 [m_alertController addAction:createAction(StandardButton(i))];
         }
-    } else {
+    } else if (customButtons.isEmpty()) {
         // We need at least one button to allow the user close the dialog
         [m_alertController addAction:createAction(NoButton)];
     }