This document discusses using the Objects library for building RingQt applications. The library provides an object-oriented approach to managing GUI objects and connecting events. It supports creating multiple windows from the same controller class. Key points: - The Open_Window() function opens new windows from controller classes derived from WindowsControllerParent. - Views are defined in classes derived from WindowsViewParent and contain a 'win' attribute for the GUI object. - Method() determines the controller method executed on events. - Last_Window() returns the last opened window controller for calling methods like SetParentObject(). - Controller classes contain CloseAction() by default to close windows. An example creates a main window with

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Table 47.1 – continued from previous page
Class Name Methods to use the default Events
QTcpServer SetAcceptErrorEvent()
SetNewConnectionEvent()
QIODevice SetAboutToCloseEvent()
SetBytesWrittenEvent()
SetReadChannelFinishedEvent()
SetReadyReadEvent()
QAbstractSocket SetConnectedEvent()
SetDisconnectedEvent()
SetErrorEvent()
SetHostFoundEvent()
SetProxyAuthenticationRequiredEvent()
SetStateChangedEvent()
QTcpSocket SetConnectedEvent()
SetDisconnectedEvent()
SetErrorEvent()
SetHostFoundEvent()
SetProxyAuthenticationRequiredEvent()
SetStateChangedEvent()
SetAboutToCloseEvent()
SetBytesWrittenEvent()
SetReadChannelFinishedEvent()
SetReadyReadEvent()
QColorDialog SetColorSelectedEvent()
SetCurrentColorChangedEvent()
QNetworkAccessManager SetFinishedEvent()
QThread SetStartedEvent()
SetFinishedEvent()
47.55 Methods to use Events with Events Filter
RingQt define a new class called QAllEvents that help you in using Events Filter
The next table presents the methods that we have
Methods to get parameters Class Name
getKeyCode() –> Number QAllEvents
getx() –> Number
gety() –> Number
getglobalx() –> Number
getglobaly() –> Number
getbutton() –> Number
getbuttons() –> Number
The next table presents the methods that we have to use events.
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Method Name Class Name
setKeyPressEvent(cEvent) QAllEvents
setMouseButtonPressEvent(cEvent)
setMouseButtonReleaseEvent(cEvent)
setMouseButtonDblClickEvent(cEvent)
setMouseMoveEvent(cEvent)
setCloseEvent(cEvent)
setContextMenuEvent(cEvent)
setDragEnterEvent(cEvent)
setDragLeaveEvent(cEvent)
setDragMoveEvent(cEvent)
setDropEvent(cEvent)
setEnterEvent(cEvent)
setFocusInEvent(cEvent)
setFocusOutEvent(cEvent)
setKeyReleaseEvent(cEvent)
setLeaveEvent(cEvent)
setNonClientAreaMouseButtonDblClickEvent(cEvent)
setNonClientAreaMouseButtonPressEvent(cEvent)
setNonClientAreaMouseButtonReleaseEvent(cEvent)
setNonClientAreaMouseMoveEvent(cEvent)
setMoveEvent(cEvent)
setResizeEvent(cEvent)
setWindowActivateEvent(cEvent)
setWindowBlockedEvent(cEvent)
setWindowDeactivateEvent(cEvent)
setWindowStateChangeEvent(cEvent)
setWindowUnblockedEvent(cEvent)
47.56 The Difference between Qt and RingQt
1. RingQt use simple methods to set the code that will be executed for events.
Syntax:
Set<Event_Name>Event(cEventCode)
2. RingQt change the name of some methods to avoid conflict with Ring Keywords.
The next table present these little changes
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Class Name Qt Method Name RingQt Method Name
QWebView load loadpage
QMediaPlaylist load loadfile
QMediaPlaylist next movenext
QPainter end endpaint
QPicture load loadfile
QLineEdit end endtext
QDialog done donedialog
QTextDocument end enddoc
QTextBlock next nextblock
QSqlQuery next movenext
QImage load loadimage
QNetworkAccessManager get getvalue
QNetworkAccessManager put putvalue
QThread exit exitfromthread
QRegularExpressionMatchIterator next nextitem
QCamera load loadcamera
47.57 RingQt Classes and their Qt Documentation
Qt Documentation : http://doc.qt.io/qt-5/classes.html
See the “RingQt Classes and Methods Reference” chapter for supported classes and methods.
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4. CHAPTER
FORTYEIGHT
BUILDING RINGQT APPLICATIONS FOR MOBILE
In this chapter we will learn about Building RingQt Applications for Mobile.
48.1 Download Requirements
Check the next link : http://doc.qt.io/qt-5/androidgs.html
Download
• The Android SDK Tools
https://developer.android.com/studio/index.html
• The Android NDK
https://developer.android.com/ndk/index.html
• Apache Ant v1.8 or later
http://ant.apache.org/bindownload.cgi
• Java SE Development Kit (JDK) v6 or later
http://www.oracle.com/technetwork/java/javase/downloads/jdk7-downloads-1880260.html
48.2 Update the Android SDK
Update the Android SDK to get the API and tools packages required for development
48.3 Install Qt for Android
• You can install Qt for Android from the next link
https://download.qt.io/archive/qt/5.5/5.5.1/
• Run Qt Creator, Select Tools > Options > Android to add the Android NDK and SDK paths.
http://doc.qt.io/qtcreator/creator-developing-android.html
• Using Qt Creator Open the project
Folder : ring/android/ringqt/project
Project file : project.pro
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• You will find the code in resourcestest.ring
You can modify the code then build and run for Desktop or Mobile.
48.4 Comments about developing for Android using RingQt
1. The main project file is main.cpp
This file load Ring Compiler/Virtual Machine and RingQt
Then copy files during the runtime from the resources to temp. folder
Then run the test.ring
Through main.cpp you can extract more files from the resources to temp. folder once you add them
(create projects with many files).
2. The next functions are missing from this Ring edition
• Database (ODBC, SQLite & MySQL)
• Security and Internet functions (LibCurl & OpenSSL)
• RingAllegro (Allegro Library)
• RingLibSDL (LibSDL Library)
Just use Qt Classes through RingQt.
For database access use the QSqlDatabase Class
Note: All of the missing libraries ((LibCurl, OpenSSL & Allegro) can be compiled for Android, but they are not
included in this Qt project.
3. use if isandroid() when you want to modify the code just for android
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Example:
if isandroid()
// Android code
else
// other platforms
ok
(4) Sometimes you will find that the button text/image is repeated in drawing ! it’s Qt problem that you can avoid
using the next code.
if isandroid()
setStyleSheet("
border-style: outset;
border-width: 2px;
border-radius: 4px;
border-color: black;
padding: 6px;")
ok
5. Always use Layouts instead of manual setting of controls position and size.
This is the best way to get the expected user interface to avoid problems like (controls with small/extra size)
6. When you deal with Qt Classes you can determine the images from resources (you don’t need to copy them
using main.cpp)
Example:
if isandroid()
mypic = new QPixmap(":/resources/cardsimage")
else
mypic = new QPixmap("cards.jpg")
ok
In the previous example, cards.jpg is added to the resources then we write the “cardsimage” as alias for “cards.jpg”
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7. CHAPTER
FORTYNINE
OBJECTS LIBRARY FOR RINGQT APPLICATION
In this chapter we will learn about the objects library for RingQt applications.
Ring 1.2 comes with the Objects library for RingQt applications. Instead of using global variables for windows
objects and connecting events to objects using the object name, the Objects Library will manage the GUI objects and
will provide a more natural API to quickly create one or many windows from the same class and the 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.
The Objects Library is designed to be used with the MVC Design Pattern.
The Objects Library is merged in RingQt so you can use it directly when you use RingQt
49.1 Library Usage
• Use the Open_Window(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 Last_Window() 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 Open_Window() It will be called.
• In the view class, Define the GUI window object as an attribute called win.
49.2 Example
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.
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• 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 {
open_window( :MainWindowController )
exec()
}
class MainWindowController from WindowsControllerParent
oView = new MainWindowView
func SubWindowAction
Open_window( :SubWindowController )
Last_Window().SetParentObject(self)
class MainWindowView from WindowsViewParent
win = new qWidget() {
SetWindowTitle("Main Window")
btnSub = new qPushButton(win) {
setText("Sub Window")
setClickEvent( Method( :SubWindowAction ) )
}
resize(400,400)
}
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) {
Move(200,0)
setText("Close")
setClickEvent( Method( :CloseAction ) )
}
resize(400,400)
}
The next screen shot after creating three sub windows.
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The next screen shot after clicking on the button in each sub window.
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49.3 Objects Library Source Code
The library source code is very simple, You can check the source code files
• https://github.com/ring-lang/ring/blob/master/extensions/ringqt/objectslib/objects.ring
• https://github.com/ring-lang/ring/blob/master/extensions/ringqt/objectslib/subwindows.ring
# List of objects (Windows/Forms)
$RingQt_ObjectsList = [] # Contains sub lists [object ID , Object]
# The Object ID Counter
$RingQt_ObjectID = 0
# Variable used for Windows/Forms object name - used for setting events
$RingQt_ObjName = ""
# The next constants for the Objects List
C_RINGQT_OBJECTSLIST_ID = 1
49.3. Objects Library Source Code 489