This document provides code examples for creating a mouse event filter and handling mouse events like press, release, and move in Qt. It also includes examples for inheritance from GUI classes, using the QDesktopWidget class to center windows, rotating text using a timer, changing widget focus using keyboard input, using regular expressions, and creating a simple client-server application in Qt with TCP sockets.

1. Ring Documentation, Release 1.9
myfilter.setMouseButtonPressEvent("pPress()")
myfilter.setMouseButtonReleaseEvent("pRelease()")
myfilter.setMouseMoveEvent("pMove()")
installeventfilter(myfilter)
}
show()
}
exec()
}
Func pEnter
Label1.setStyleSheet("background-color: purple; color:white;font-size: 30pt;")
Func pLeave
Label1.setStyleSheet("background-color: white; color:black;font-size: 30pt;")
Func pPress
lPress = True
nX = myfilter.getglobalx()
ny = myfilter.getglobaly()
Func pRelease
lPress = False
pEnter()
Func pMove
nX2 = myfilter.getglobalx()
ny2 = myfilter.getglobaly()
ndiffx = nX2 - nX
ndiffy = nY2 - nY
if lPress
Label1 {
move(x()+ndiffx,y()+ndiffy)
setStyleSheet("background-color: Green;
color:white;font-size: 30pt;")
nX = nX2
ny = nY2
}
ok
The application during the runtime
64.47. Moving Objects using the Mouse 729

2. Ring Documentation, Release 1.9
64.47. Moving Objects using the Mouse 730

3. Ring Documentation, Release 1.9
64.47. Moving Objects using the Mouse 731

4. Ring Documentation, Release 1.9
64.48 Inheritance from GUI Classes
Example :
Load "guilib.ring"
New MyWindow()
new qApp { exec() }
class mywindow from qwidget
Func init
super.init()
setwindowtitle("First Window")
setgeometry(100,100,400,400)
setstylesheet("background-color: purple;")
settooltip("my first window!")
show()
The application during the runtime
64.48. Inheritance from GUI Classes 732

5. Ring Documentation, Release 1.9
64.49 Using QDesktopWidget Class
In the next example we will learn about using the QDesktopWidget class
Load "guilib.ring"
New qApp {
win1 = New qWidget()
{
resize(400,400)
btn1 = new qPushbutton(win1)
{
setText("Center")
move(100,100)
resize(100,30)
setClickEvent("pCenter()")
}
Show()
}
exec()
}
Func pCenter
oDesktop = new qDesktopWidget()
64.49. Using QDesktopWidget Class 733

6. Ring Documentation, Release 1.9
oRect = oDesktop.screenGeometry( oDesktop.primaryScreen() )
win1.move((oRect.width()-win1.width()) /2 , (oRect.Height()-win1.Height())/2 )
win1.show()
The application during the runtime
64.50 Rotate Text
The next example rotate text using a Timer.
Load "guilib.ring"
nAngle = 0
New qapp {
win1 = new qwidget() {
setwindowtitle("Rotate Text")
resize(800,600)
label1 = new qlabel(win1) {
settext("")
myfilter = new qallevents(win1)
myfilter.setMouseButtonPressevent("pClick()")
installeventfilter(myfilter)
}
new qtimer(win1) {
setinterval(50)
64.50. Rotate Text 734

7. Ring Documentation, Release 1.9
settimeoutevent("pTime()")
start()
}
pDraw()
L1 = new qVBoxLayout() { AddWidget(Label1) } SetLayout(L1)
showMaximized()
}
exec()
}
Func pDraw
p1 = new qpicture()
color = new qcolor() {
setrgb(0,0,255,255)
}
pen = new qpen() {
setcolor(color)
setwidth(50)
}
painter = new qpainter() {
begin(p1)
setpen(pen)
myfont = font()
myfont.setpointsize(50)
setfont(myfont)
rotate(nAngle)
drawtext(350,0*nAngle,"welcome")
drawtext(0,0*nAngle,"welcome")
endpaint()
}
label1 {
setpicture(p1)
show()
}
Func pClick
win1 { setwindowtitle("Click Event") }
Func pTime
nAngle++
if nAngle = 90
nAngle = 10
ok
pDraw()
The application during the runtime
64.50. Rotate Text 735

8. Ring Documentation, Release 1.9
64.51 Change Focus
The next example change the focus using the ENTER key.
load "guilib.ring"
new qApp {
win = new qWidget() {
resize(600,600)
SetWindowTitle("Change Focus")
text1 = new qLineEdit(win)
text2 = new qLineEdit(win)
text3 = new qLineEdit(win)
text4 = new qLineEdit(win)
layout1 = new qVBoxLayout() {
AddWidget(text1)
AddWidget(text2)
AddWidget(text3)
AddWidget(text4)
}
setLayout(Layout1)
64.51. Change Focus 736

9. Ring Documentation, Release 1.9
aList = [text1,text2,text3,text4]
oFilter = new qallevents(win)
oFilter.setKeyPressEvent("pWork()")
installeventfilter(oFilter)
show()
}
exec()
}
func pWork
nCode = oFilter.getkeycode()
if nCode = 16777220 # ENTER Key
for x=1 to len(aList)
if aList[x].HasFocus()
t = x+1
if t > len(aList) t=1 ok
aList[t].SetFocus(0)
exit
ok
next
ok
64.52 Regular Expressions
The next example uses the Regular Expressions classes.
load "guilib.ring"
new qApp
{
see "Using Regular Expressions" + nl
exp = new qregularexpression() {
setPattern("dd w+")
see pattern() + nl
match = match("33 one",0,0,0)
see match.hasmatch() + nl
match = match("3 one",0,0,0)
see match.hasmatch() + nl
match = match("welcome 11 one",0,0,0)
see match.hasmatch() + nl
matched = match.captured(0)
see matched + nl
}
exp = new qregularexpression() {
setPattern("^(dd)/(dd)/(dddd)$")
see pattern() + nl
match = match("08/12/1985",0,0,0)
see match.hasmatch() + nl
day = match.captured(1)
month = match.captured(2)
year = match.captured(3)
see day + nl + month + nl + year + nl
see "(" + match.capturedStart(1) + "," + match.capturedEnd(1)+ ")" + nl
see "(" + match.capturedStart(2) + "," + match.capturedEnd(2)+ ")" + nl
see "(" + match.capturedStart(3) + "," + match.capturedEnd(3)+ ")" + nl
64.52. Regular Expressions 737

10. Ring Documentation, Release 1.9
}
}
Output
Using Regular Expressions
dd w+
1
0
1
11 one
^(dd)/(dd)/(dddd)$
1
08
12
1985
(0,2)
(3,5)
(6,10)
64.53 Simple Client and Server Example
In this section we will learn about creating simple Client and Server Application
Load "guilib.ring"
new qApp {
oClient = new Client { client() }
oServer = new Server { server() }
exec()
}
Class Client
win1 lineedit1 cOutput=""
oTcpSocket
func client
win1 = new qwidget()
new qpushbutton(win1) {
setgeometry(50,50,100,30)
settext("connect")
setclickevent("oClient.Connect()")
}
lineedit1 = new qtextedit(win1) {
setGeometry(150,50,200,300)
}
win1 {
setwindowtitle("client")
setgeometry(10,100,400,400)
show()
64.53. Simple Client and Server Example 738