Switching from native iOS gui to Qt gui
<p>I currently have a native iOS GUI and a Qt-GUI. I'm trying to switch from one to another.</p>

<p>To be clear: When i click on a button on the native GUI i want the Qt-GUI to show up and vice versa.</p>

<p>I already found out which libraries i have to add to be able to use the Qt-Stuff. I created a <code>QApplication</code> in the <code>AppDelegate.mm</code> file:</p>

<pre><code>- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions: (NSDictionary *) launchOptions {
    // receive int argc, and char** argv for the QApplication.
    _qApp = new QApplication(_argc, _argv);
}
</code></pre>

<p>Furthermore my Qt application looks (at the moment) like this:</p>

<pre><code>void createQtGUI() {
    QPushButton* btn = new QPushButton("Some Button");
    QLabel* lbl = new QLabel("QTGui");
    QVBoxLayout* layout = new QVBoxLayout();
    layout-&gt;addWidget(lbl);
    layout-&gt;addWidget(btn);

    QWidget* window = new QWidget();
    window-&gt;setLayout(layout);
    window-&gt;show();
}
</code></pre>

<p>I'm calling the <code>createQtGUI</code> method in my <code>ViewController.mm</code> when pressing a button in the native iOS GUI. The code runs without throwing any error, but:</p>

<p><strong>The Qt-GUI is not shown. The application still shows the native gui without switching to the Qt-GUI.</strong></p>

<p>Has anybody got any idea how to fix that?</p>