Objects Library for RingQt Application

In this chapter we will learn about the objects library and using it in GUI applications.

Instead of using global variables for windows objects and connecting events to objects using the object name, the Objects Library will manage a list of the GUI objects and will provide a more natural API to quickly create one or many windows from the same class.

Also the Objects Library provide a way to quickly set methods to be executed when an event is fired. Also the library provide a natural interface to quickly use the parent or the caller windows from the child or sub windows and the other way around.

The Objects Library is designed to be used with the MVC Design Pattern.

The Objects Library uses reflection and meta-programming to add new methods to Controller classes to provide an easy way for communication between these classes.

The Objects Library is called automatically by the GUILib

Also we can call it alone by using the next command

load "objectslib.ring"

The ObjectsLib provide functions like openObject(), lastObject() and a class called ObjectsParent

The GUILib provide a new specific API for GUI applications like openWindow(), lastWindow(), etc.

Library Usage with GUI Applications

  • Use the openWindow(cWindowControllerClassName) function to open new Windows

  • Create at least Two Classes for each window, The Controller Class and the View Class

  • Create each controller class from the WindowsControllerParent Class

  • Create each view class from the WindowsViewParent Class

  • Use the lastWindow() function to get the object of the last window created (The Controller object).

  • When you call a sub window, use the SetParentObject() method and pass the self object.

  • In the View Class, To determine the event method use the Method(cMethodName) function.

  • The Method(cMethodName) function determine the method in the controller class that will be executed.

  • Each controller class contains by default the CloseAction() method that you can call to close the window.

  • You don’t need to call the Show() Method for each window, When you use openWindow() It will be called.

  • In the view class, Define the GUI window object as an attribute called win.

  • You can use openWindowNoShow() to avoid displaying the window.

  • You can use openWindowAndLink() to quickly get methods to access the windows.


In the next example we will create two types of windows.

  • Main Window contains a button. When the user click on the button a sub window will be opened.

  • The User Can click on the button many times to open many sub windows.

  • Each Sub Window contains Two buttons.

  • The first button in the sub window change the Main and the Sub Windows Titles.

  • The second button in the sub window close the Sub Window.

load "guilib.ring"

new qApp {
        openWindow( :MainWindowController )

class MainWindowController from WindowsControllerParent
        oView = new MainWindowView
        func SubWindowAction
                openWindow( :SubWindowController )

class MainWindowView from WindowsViewParent
        win = new qWidget() {
                SetWindowTitle("Main Window")
                btnSub = new qPushButton(win) {
                        setText("Sub Window")
                        setClickEvent( Method( :SubWindowAction ) )

class SubWindowController from WindowsControllerParent
        oView = new SubWindowView
        func SetMainWindowTitleAction
                Parent().oView.win.SetWindowTitle("Message from the Sub Window")
                oView.win.SetWindowTitle("Click Event Done!")

class SubWindowView from WindowsViewParent
        win = new qWidget() {
                SetWindowTitle("Sub Window")
                btnMsg = new qPushButton(win) {
                        setText("Set Main Window Title")
                        setClickEvent( Method( :SetMainWindowTitleAction ) )
                btnClose = new qPushButton(win) {
                        setClickEvent( Method( :CloseAction ) )

The next screen shot after creating three sub windows.

Objects Library Example - Shot 1

The next screen shot after clicking on the button in each sub window.

Objects Library Example - Shot 2

openWindowInPackages() Function

The openWindowInPackages() function is the same as openWindow() but takes an extra list that determine the packages to import before opening the window.




The next example from the Form Designer source code, Open the Window Flags window using the openWindowInPackages() function.

We determine the class name “WindowFlagsController” and the packages name.

The Window Flags window uses the FormDesigner and System.GUI packages.


Objects Library Source Code

The library source code is very simple, You can check the source code files

The source code for the Objects Library (can be used without GUILib)

The source code for the MVC classes in GUILib