ndefeditor: fix dropdown menu problems

Because of QTBUG-98651 and QTBUG-97482 a QPushButton with a dropdown
menu was not working properly neither on iOS nor on Android.
This patch fixes the issue, but it's not optimal, because it re-creates
the menu every time.
Ideally we should provide QML-based GUI for the example.

Task-number: QTBUG-103949
Pick-to: 6.3 6.2
Change-Id: Icd1e00f27f5c4864a33fa7f1f7755c0e919183cb
Reviewed-by: Juha Vuolle <juha.vuolle@insta.fi>

2 files changed, 27 insertions, 6 deletions

diff --git a/examples/nfc/ndefeditor/mainwindow.cpp b/examples/nfc/ndefeditor/mainwindow.cpp
index 87042d4c..f39f8d7a 100644
--- a/examples/nfc/ndefeditor/mainwindow.cpp
+++ b/examples/nfc/ndefeditor/mainwindow.cpp
@@ -134,12 +134,7 @@ MainWindow::MainWindow(QWidget *parent)
 {
     ui->setupUi(this);
 
-    QMenu *addRecordMenu = new QMenu(this);
-    addRecordMenu->addAction(tr("NFC Text Record"), this, SLOT(addNfcTextRecord()));
-    addRecordMenu->addAction(tr("NFC URI Record"), this, SLOT(addNfcUriRecord()));
-    addRecordMenu->addAction(tr("MIME Image Record"), this, SLOT(addMimeImageRecord()));
-    addRecordMenu->addAction(tr("Empty Record"), this, SLOT(addEmptyRecord()));
-    ui->addRecord->setMenu(addRecordMenu);
+    connect(ui->addRecord, &QPushButton::clicked, this, &MainWindow::showMenu);
 
     QVBoxLayout *vbox = new QVBoxLayout;
     ui->scrollAreaWidgetContents->setLayout(vbox);
@@ -368,6 +363,28 @@ void MainWindow::targetError(QNearFieldTarget::Error error, const QNearFieldTarg
     }
 }
 
+void MainWindow::showMenu()
+{
+    // We have to manually call QMenu::popup() because of QTBUG-98651.
+    // And we need to re-create menu each time because of QTBUG-97482.
+    if (m_menu) {
+        m_menu->setParent(nullptr);
+        delete m_menu;
+    }
+    m_menu = new QMenu(this);
+    m_menu->addAction(tr("NFC Text Record"), this, &MainWindow::addNfcTextRecord);
+    m_menu->addAction(tr("NFC URI Record"), this, &MainWindow::addNfcUriRecord);
+    m_menu->addAction(tr("MIME Image Record"), this, &MainWindow::addMimeImageRecord);
+    m_menu->addAction(tr("Empty Record"), this, &MainWindow::addEmptyRecord);
+
+    // Use menu's sizeHint() to position it so that its right side is aligned
+    // with button's right side.
+    QPushButton *button = ui->addRecord;
+    const int x = button->x() + button->width() - m_menu->sizeHint().width();
+    const int y = button->y() + button->height();
+    m_menu->popup(mapToGlobal(QPoint(x, y)));
+}
+
 void MainWindow::clearMessage()
 {
     QWidget *scrollArea = ui->scrollAreaWidgetContents;
diff --git a/examples/nfc/ndefeditor/mainwindow.h b/examples/nfc/ndefeditor/mainwindow.h
index df63b459..e63fd36f 100644
--- a/examples/nfc/ndefeditor/mainwindow.h
+++ b/examples/nfc/ndefeditor/mainwindow.h
@@ -58,6 +58,7 @@
 QT_FORWARD_DECLARE_CLASS(QNearFieldManager)
 QT_FORWARD_DECLARE_CLASS(QNdefMessage)
 QT_FORWARD_DECLARE_CLASS(QScreen)
+QT_FORWARD_DECLARE_CLASS(QMenu)
 
 QT_BEGIN_NAMESPACE
 namespace Ui {
@@ -98,6 +99,8 @@ private slots:
     void ndefMessageWritten(const QNearFieldTarget::RequestId &id);
     void targetError(QNearFieldTarget::Error error, const QNearFieldTarget::RequestId &id);
 
+    void showMenu();
+
 private:
     enum TouchAction {
         NoAction,
@@ -111,6 +114,7 @@ private:
 
 private:
     Ui::MainWindow *ui;
+    QMenu *m_menu = nullptr;
 
     QNearFieldManager *m_manager;
     TouchAction m_touchAction;