How to position NSPanel at center of app window

Question

I'm very new to Macos development and there's barely any information available online but I cannot seem to figure out how to position my NSpanel at the top center of my app window. It opens in the center of my whole screen.

let dialog = NSOpenPanel()
            dialog.title = "Choose a file!"
            dialog.showsResizeIndicator = true;
            dialog.showsHiddenFiles = false;
            dialog.allowsMultipleSelection = false;
            dialog.canChooseDirectories = false;
            dialog.allowedFileTypes = ["py"];
            dialog.isFloatingPanel = false;

this is my current code

Answer 1

You can do the following

let dialog = NSOpenPanel()
    dialog.title = "Choose a file!"
    dialog.showsResizeIndicator = true;
    dialog.showsHiddenFiles = false;
    dialog.allowsMultipleSelection = false;
    dialog.canChooseDirectories = false;
    dialog.allowedFileTypes = ["py"];

// here `window` is your document or main window (eg: `NSApp.mainWindow!`, etc.)
dialog.beginSheetModal(for: window) { result in
    if result == .OK {
        // do read a file
    }
}