[SOLVED] Running GUI application executable does not show the main window

  • I am trying to learn C++, Qt and QML by writing a simple app, but I am having trouble running the executable after I compile it. This is the code in main.cpp

    #include <QtGui/QGuiApplication>
    #include <QtQml/QQmlApplicationEngine>
    #include <QtCore/QUrl>
    #include <QtQml/QQmlContext>
    #include <aboutappdialog.h>
    #include <aboutqtdialog.h>
    int main(int argc, char *argv[])
        QGuiApplication app(argc, argv);
        QQmlApplicationEngine engine;
        AboutAppDialog aboutApp;
        AboutQtDialog aboutQt;
        engine.rootContext()->setContextProperty("aboutApp", &aboutApp);
        engine.rootContext()->setContextProperty("aboutQt", &aboutQt);
        return app.exec();

    And this is the code of main.qml:

    ApplicationWindow {
        id: mainWindow
        title: "MyApp"
        minimumHeight: 420
        minimumWidth: 420
        visibility: Window.AutomaticVisibility
        menuBar: MenuBar {
            Menu {
                title: qsTr("App")
                MenuItem {
                    text: qsTr("New")
                    shortcut: "Ctrl+N"
                    onTriggered: Qt.quit() // change this
                MenuItem {
                    text: qsTr("Quit")
                    shortcut: "Alt+F4"
                    onTriggered: Qt.quit()
            Menu {
                title: qsTr("Tools")
                MenuItem {
                    text: qsTr("Options")
                    shortcut: "Ctrl+O"
                    onTriggered: Qt.quit() //change this
            Menu {
                title: qsTr("About")
                MenuItem {
                    text: qsTr("About Quick Tac Toe")
                    onTriggered: { aboutApp = new AboutAppDialog(mainWindow);
                                  aboutApp.aboutApp(mainWindow); }
                MenuItem {
                    text: qsTr("About Qt")
                    onTriggered: { aboutQt = new AboutQtDialog(mainWindow);
                                   aboutQt.aboutQt(mainWindow); }

    When I run the executable from the command line after building it, all I get is the following message: using qt5ct plugin

    When I run qmlscene main.qml it does show the GUI as expected, but upon clicking the menu items for the "About" dialogs defined in C++, I get errors like this: ReferenceError: AboutAppDialog is not defined

    So the question is simple: what am I doing wrong. Thanks in advance.

  • What if you add visible: true to main.qml?

  • @Paul-H. D'oh! Why, of course, how silly of me. visibility: Window.AutomaticVisibility does NOT automatically do visible: true.

    Truly a case of needing to ask someone else to realize you're making a rookie mistake. Thanks for your help, Paul.

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