Tkinter GUI application development cookbook packt publishing (2018)

TkinterGUIApplicationDevelopmentCookbook


ApracticalsolutiontoyourGUIdevelopmentproblemswith
PythonandTkinter








AlejandroRodasdePaz













BIRMINGHAM-MUMBAI

TkinterGUIApplication
DevelopmentCookbook
Copyright©2018PacktPublishing
Allrightsreserved.Nopartofthisbookmaybereproduced,storedinaretrievalsystem,ortransmittedinany
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Contributors


Abouttheauthor
AlejandroRodasdePazisacomputerengineerfromSeville,
Spain.HehasdevelopedseveralprojectswithPython,fromweb
crawlerstoartificialintelligencealgorithms.Hehasalsoused
Tkinterforbuildinganapplicationforthelightingsystemofthecity
ofAlmere(Netherlands).
Priortothispublication,Alejandroco-wrotePackt'stitlePython
GameDevelopmentbyExample,andcollaboratedasatechnical
revieweronthebookTkinterGUIApplicationDevelopment
Hotshot.
IwouldliketothanktheexceptionalteamatPacktPublishingfortheirassistanceduring
thisjourney,andwordscannotexpressmygratitudetoJasonandPrajaktafortheir
understandingandimmensepatience.


Aboutthereviewers
JavierBecerraElcintoreceivedhisPhDinimageprocessing
fromtheUniversitédeBordeauxin2006.In2010hestarted
workingasaself-employeddeveloperworkingwithPythonand
C++,andin2014hecofoundedPanoimagenS.L.There,hehas

continuedtodevelopsoftwareforindustrialandprecision
agricultureapplications.Javierlecturesregularlyonscientific
programminginprivatecompaniesandseveralSpanishresearch
institutions.

MarcosPerezGonzalezworksinthetreatmentofmultimedia
documentdatabaseswithPython.Previously,hehadbeenusingit
asgluebetweenprojectsandtechnologiesformorethan10years.
Atthebeginningofhiscareer,heusedPythonforembedding
purposesandmultiplatformGUIprogramming.
HeisamemberofthePythonSpainassociationandthePython
Madridmeetup.Moreover,hehasbeenamemberoftheboardof
directorsoftheSpanishAssociationofComputerEngineering.
Heholdsamaster'sdegreeincomputerengineeringfromthe
UniversityofValladolid.

BrysonTyrrellisasystemsdevelopmentengineeratJamfin
Minneapolis,Minnesota.Inadditiontotheresponsibilitiesofhis
role,BrysonhasspokenatvariousITconferences(includingthe
JamfNationUserConference,PennStateMacAdmins,MacAdmins
andDevelopersUK,andAtlassianSummit)andmaintainsa


numberofopensourcetoolsfortheMacadmincommunityonhis
GitHubaccount.



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Preface
Asoneofthemoreversatileprogramminglanguages,Pythoniswell
knownforitsbatteries-includedphilosophy,whichincludesarich
setofmodulesinitsstandardlibrary;Tkinteristhelibraryusedto
builddesktopapplications.BuiltovertheTkGUItoolkit,Tkinteris
acommonchoiceforrapidGUIdevelopment,andcomplex
applicationscanbenefitfromthefullcapabilitiesofthislibrary.
ThisbookcoversallofyourTkinterandPythonGUIdevelopment
problemsandsolutions.
TkinterGUIApplicationDevelopmentCookbookstartswithan
overviewofTkinterclassesandatthesametimeprovidesrecipes
forbasictopics,suchaslayoutpatternsandeventhandling.Next,
thisbookcovershowtodevelopcommonGUIpatterns,suchas
enteringandsavingdata,navigatingthroughmenusanddialogs,
andperforminglong-runningactionsinthebackground.Youcan
thenmakeyourappsleveragenetworkresourceseffectivelyand
performgraphicaloperationsonacanvasandrelatedtaskssuchas
detectingcollisionsbetweenitems.Finally,thisbookcoversusing
themedwidgets,anextensionofTkwidgetsthathaveamorenative
lookandfeel.
Bytheendofthebook,youwillhaveanin-depthknowledgeof
Tkinterclassesandknowhowtousethemtobuildefficientandrich

GUIapplications.


Whothisbookisfor
ThisbooktargetsPythondeveloperswhoarefamiliarwiththe
basicsofthelanguage—syntax,datastructures,andOOP—wantsto
learneffectivesolutionstothecommonchallengesofGUI
development,anddesirestodiscoverinterestingcapabilitiesthat
Tkintercanoffertobuildcomplexapplications.
YoudonotneedpreviousexperiencewithTkinterorotherGUI
developmentlibrariessincethefirstpartofthebookwillteachthe
basicsofthelibrarythroughtheintroductoryusecases.


Whatthisbookcovers
,GettingStartedwithTkinter,introducesthestructureofa
Tkinterprogramandshowsyouhowtoperformthemostcommon
tasks,suchascreatingwidgetsandhandlinguserevents.
Chapter1

,WindowLayout,demonstrateshowtoplacewidgetsusing
geometrymanagersandimprovethelayoutoflargeapplications.
Chapter2

,CustomizingWidgets,divesdeeperintoTkinter'swidget
configurationandappearancecustomization.
Chapter3

,DialogsandMenus,teachesyouhowtoimprovethe
navigationofTkinterappswithmenusanddialogs.

Chapter4

,Object-OrientedProgrammingandMVC,teachesyouhow
toeffectivelyapplydesignpatternsinyourTkinterapplications.
Chapter5

,AsynchronousProgramming,coversseveralrecipesto
executelong-runningactionswithoutfreezingtheapplication—a
recurringprobleminGUIdevelopment.
Chapter6

,CanvasandGraphics,explorestheCanvaswidgetandthe
typesofitemsyoucanaddtothecanvasandhowtomanipulate
them.
Chapter7

,ThemedWidgets,teachesyouhowtoextendTkinter
applicationswiththeTk-themedwidgetset.
Chapter8


Togetthemostoutofthis
book
Togetupandrunning,userswillneedtohavethefollowing
technologiesinstalled:
Python3.x
Anyoperatingsystem


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Conventionsused
Thereareanumberoftextconventionsusedthroughoutthisbook.
:Indicatescodewordsintext,databasetablenames,folder
names,filenames,fileextensions,pathnames,dummyURLs,user
input,andTwitterhandles.Hereisanexample:
"Thedelete()methodtakestwoargumentsthatindicatetherangeof
thecharactersthatshouldbedeleted."
CodeInText

Ablockofcodeissetasfollows:
fromtkinterimport*

root=Tk()
btn=Button(root,text="Clickme!")
btn.config(command=lambda:print("Hello,Tkinter!"))
btn.pack(padx=120,pady=30)
root.title("MyTkinterapp")
root.mainloop()

Whenwewishtodrawyourattentiontoaparticularpartofacode
block,therelevantlinesoritemsaresetinbold:
defshow_caption(self,event):
caption=tk.Label(self,...)
caption.place(in_=event.widget,x=event.x,y=event.y)
#...

Bold:Indicatesanewterm,animportantword,orwordsthatyou
seeonscreen.Forexample,wordsinmenusordialogboxesappear
inthetextlikethis.Hereisanexample:"Thefirstwillbe
labeledChoosefile."


Warningsorimportantnotesappearlikethis.
Tipsandtricksappearlikethis.


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GettingStartedwithTkinter
Inthischapter,wewillcoverthefollowingrecipes:
StructuringaTkinterapplication
Workingwithbuttons
Creatingtextentries
Tracingtextchanges
Validatingatextentry
Selectingnumericalvalues
Creatingselectionswithradiobuttons
Implementingswitcheswithcheckboxes
Displayingalistofitems
Handlingmouseandkeyboardevents
Settingthemainwindow'sicon,title,andsize