The Ring programming language version 1.5.3 book - Part 76 of 184
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This document provides examples of using events and filters in Qt GUI applications. It shows how to: 1. Detect key press and mouse move events using an event filter class. 2. Allow moving a label object by getting mouse position on press, move, and release events. 3. Inherit from GUI classes like QWidget to create custom window classes.
The Ring programming language version 1.5.3 book - Part 76 of 184
- 1. Ring Documentation, Release 1.5.3 56.44 KeyPress and Mouse Move Events In this example we will learn how to use the Events Filter to know about KeyPress and Mouse Move Events Load "guilib.ring" new qApp { win1 = new qWidget() { setWindowTitle("Test using Event Filter!") setGeometry(100,100,400,400) setmousetracking(true) myfilter = new qallevents(win1) myfilter.setKeyPressEvent("pWork()") myfilter.setMouseButtonPressevent("pClick()") myfilter.setmousemoveevent("pMove()") installeventfilter(myfilter) show() } exec() } func pWork win1.setwindowtitle('KeyPress! : ' + myfilter.getkeycode()) func pClick new qmessagebox(win1) { setgeometry(100,100,400,100) setwindowtitle("click event!") settext("x : " + myfilter.getx() + " y : " + myfilter.gety() + " button : " + myfilter.getbutton() ) show() } func pMove win1.setwindowtitle("Mouse Move , X : " + myfilter.getx() + " Y : " + myfilter.gety() ) The application during the runtime 56.44. KeyPress and Mouse Move Events 625
- 2. Ring Documentation, Release 1.5.3 56.45 Moving Objects using the Mouse In the next example we will learn how to program movable objects where the user can move a label Load "guilib.ring" lPress = false nX = 0 nY = 0 new qApp { win1 = new qWidget() { setWindowTitle("Move this label!") setGeometry(100,100,400,400) setstylesheet("background-color:white;") Label1 = new qLabel(Win1){ setGeometry(100,100,200,50) setText("Welcome") setstylesheet("font-size: 30pt") myfilter = new qallevents(label1) myfilter.setEnterevent("pEnter()") myfilter.setLeaveevent("pLeave()") 56.45. Moving Objects using the Mouse 626
- 3. Ring Documentation, Release 1.5.3 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 56.45. Moving Objects using the Mouse 627
- 4. Ring Documentation, Release 1.5.3 56.45. Moving Objects using the Mouse 628
- 5. Ring Documentation, Release 1.5.3 56.45. Moving Objects using the Mouse 629
- 6. Ring Documentation, Release 1.5.3 56.46 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 56.46. Inheritance from GUI Classes 630
- 7. Ring Documentation, Release 1.5.3 56.47 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() 56.47. Using QDesktopWidget Class 631
- 8. Ring Documentation, Release 1.5.3 oRect = oDesktop.screenGeometry( oDesktop.primaryScreen() ) win1.move((oRect.width()-win1.width()) /2 , (oRect.Height()-win1.Height())/2 ) win1.show() The application during the runtime 56.48 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) 56.48. Rotate Text 632
- 9. Ring Documentation, Release 1.5.3 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 56.48. Rotate Text 633
- 10. Ring Documentation, Release 1.5.3 56.49 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) 56.49. Change Focus 634