外文文献-beginning android android起航

毕业设计外文文献原文及译文BEGINNINGANDROIDANDROID起航学生姓名学号系别专业指导教师2015年5月计算机系网络工程BEGINNINGANDROIDUSINGXMLBASEDLAYOUTSWHILEITISTECHNICALLYPOSSIBLETOCREATEANDATTACHWIDGETSTOOURACTIVITYPURELYTHROUGHJAVACODE,THEWAYWEDIDINCHAPTER4,THEMORECOMMONAPPROACHISTOUSEANXMLBASEDLAYOUTFILEDYNAMICINSTANTIATIONOFWIDGETSISRESERVEDFORMORECOMPLICATEDSCENARIOS,WHERETHEWIDGETSARENOTKNOWNATCOMPILETIMEEG,POPULATINGACOLUMNOFRADIOBUTTONSBASEDONDATARETRIEVEDOFFTHEINTERNETWITHTHATINMIND,ITSTIMETOBREAKOUTTHEXMLANDLEARNHOWTOLAYOUTANDROIDACTIVITIESTHATWAYWHATISANXMLBASEDLAYOUTASTHENAMESUGGESTS,ANXMLBASEDLAYOUTISASPECIFICATIONOFWIDGETSRELATIONSHIPSTOEACHOTHERANDTOTHEIRCONTAINERSMOREONTHISINCHAPTER7ENCODEDINXMLFORMATSPECIFICALLY,ANDROIDCONSIDERSXMLBASEDLAYOUTSTOBERESOURCES,ANDASSUCHLAYOUTFILESARESTOREDINTHERES/LAYOUTDIRECTORYINSIDEYOURANDROIDPROJECTEACHXMLFILECONTAINSATREEOFELEMENTSSPECIFYINGALAYOUTOFWIDGETSANDTHEIRCONTAINERSTHATMAKEUPONEVIEWHIERARCHYTHEATTRIBUTESOFTHEXMLELEMENTSAREPROPERTIES,DESCRIBINGHOWAWIDGETSHOULDLOOKORHOWACONTAINERSHOULDBEHAVEFOREXAMPLE,IFABUTTONELEMENTHASANATTRIBUTEVALUEOFANDROIDTEXTSTYLE“BOLD“,THATMEANSTHATTHETEXTAPPEARINGONTHEFACEOFTHEBUTTONSHOULDBERENDEREDINABOLDFACEFONTSTYLEANDROIDSSDKSHIPSWITHATOOLAAPTWHICHUSESTHELAYOUTSTHISTOOLSHOULDBEAUTOMATICALLYINVOKEDBYYOURANDROIDTOOLCHAINEG,ECLIPSE,ANTSBUILDXMLOFPARTICULARIMPORTANCETOYOUASADEVELOPERISTHATAAPTGENERATESTHERJAVASOURCEFILEWITHINYOURPROJECT,ALLOWINGYOUTOACCESSLAYOUTSANDWIDGETSWITHINTHOSELAYOUTSDIRECTLYFROMYOURJAVACODEWHYUSEXMLBASEDLAYOUTSMOSTEVERYTHINGYOUDOUSINGXMLLAYOUTFILESCANBEACHIEVEDTHROUGHJAVACODEFOREXAMPLE,YOUCOULDUSESETTYPEFACETOHAVEABUTTONRENDERITSTEXTINBOLD,INSTEADOFUSINGAPROPERTYINANXMLLAYOUTSINCEXMLLAYOUTSAREYETANOTHERFILEFORYOUTOKEEPTRACKOF,WENEEDGOODREASONSFORUSINGSUCHFILESPERHAPSTHEBIGGESTREASONISTOASSISTINTHECREATIONOFTOOLSFORVIEWDEFINITION,SUCHASAGUIBUILDERINANIDELIKEECLIPSEORADEDICATEDANDROIDGUIDESIGNERLIKEDROIDDRAW1SUCHGUIBUILDERSCOULD,INPRINCIPLE,GENERATEJAVACODEINSTEADOFXMLTHECHALLENGEISREREADINGTHEUIDEFINITIONTOSUPPORTEDITSTHATISFARSIMPLERIFTHEDATAISINASTRUCTUREDFORMATLIKEXMLTHANINAPROGRAMMINGLANGUAGEMOREOVER,KEEPINGGENERATEDXMLDEFINITIONSSEPARATEDFROMHANDWRITTENJAVACODEMAKESITLESSLIKELYTHATSOMEBODYSCUSTOMCRAFTEDSOURCEWILLGETCLOBBEREDBYACCIDENTWHENTHEGENERATEDBITSGETREGENERATEDXMLFORMSANICEMIDDLEGROUNDBETWEENSOMETHINGTHATISEASYFORTOOLWRITERSTOUSEANDEASYFORPROGRAMMERSTOWORKWITHBYHANDASNEEDEDALSO,XMLASAGUIDEFINITIONFORMATISBECOMINGMORECOMMONPLACEMICROSOFTSXAML2,ADOBESFLEX3,ANDMOZILLASXUL4ALLTAKEASIMILARAPPROACHTOTHATOFANDROIDPUTLAYOUTDETAILSINANXMLFILEANDPUTPROGRAMMINGSMARTSINSOURCEFILESEG,JAVASCRIPTFORXULMANYLESSWELLKNOWNGUIFRAMEWORKS,SUCHASZK5,ALSOUSEXMLFORVIEWDEFINITIONWHILE“FOLLOWINGTHEHERD”ISNOTNECESSARILYTHEBESTPOLICY,ITDOESHAVETHEADVANTAGEOFHELPINGTOEASETHETRANSITIONINTOANDROIDFROMANYOTHERXMLCENTEREDVIEWDESCRIPTIONLANGUAGEOK,SOWHATDOESITLOOKLIKEHEREISTHEBUTTONFROMTHEPREVIOUSCHAPTERSSAMPLEAPPLICATION,CONVERTEDINTOANXMLLAYOUTFILE,FOUNDINTHELAYOUTS/NOWREDUXSAMPLEPROJECTTHISCODESAMPLEALONGWITHALLOTHERSINTHISCHAPTERCANBEFOUNDINTHESOURCECODEAREAOFHTTP/APRESSCOMTHECLASSNAMEOFTHEWIDGETBUTTONFORMSTHENAMEOFTHEXMLELEMENTSINCEBUTTONISANANDROIDSUPPLIEDWIDGET,WECANJUSTUSETHEBARECLASSNAMEIFYOUCREATEYOUROWNWIDGETSASSUBCLASSESOFANDROIDVIEWVIEW,YOUWOULDNEEDTOPROVIDEAFULLPACKAGEDECLARATIONASWELLTHEROOTELEMENTNEEDSTODECLARETHEANDROIDXMLNAMESPACEXMLNSANDROID“HTTP/SCHEMASANDROIDCOM/APK/RES/ANDROID“ALLOTHERELEMENTSWILLBECHILDRENOFTHEROOTANDWILLINHERITTHATNAMESPACEDECLARATIONBECAUSEWEWANTTOREFERENCETHISBUTTONFROMOURJAVACODE,WENEEDTOGIVEITANIDENTIFIERVIATHEANDROIDIDATTRIBUTEWEWILLCOVERTHISCONCEPTINGREATERDETAILLATERINTHISCHAPTERTHEREMAININGATTRIBUTESAREPROPERTIESOFTHISBUTTONINSTANCEANDROIDTEXTINDICATESTHEINITIALTEXTTOBEDISPLAYEDONTHEBUTTONFACEINTHISCASE,ANEMPTYSTRINGANDROIDLAYOUT_WIDTHANDANDROIDLAYOUT_HEIGHTTELLANDROIDTOHAVETHEBUTTONSWIDTHANDHEIGHTFILLTHE“PARENT”,INTHISCASETHEENTIRESCREENTHESEATTRIBUTESWILLBECOVEREDINGREATERDETAILINCHAPTER7SINCETHISSINGLEWIDGETISTHEONLYCONTENTINOURACTIVITY,WEONLYNEEDTHISSINGLEELEMENTCOMPLEXUISWILLREQUIREAWHOLETREEOFELEMENTS,REPRESENTINGTHEWIDGETSANDCONTAINERSTHATCONTROLTHEIRPOSITIONINGALLTHEREMAININGCHAPTERSOFTHISBOOKWILLUSETHEXMLLAYOUTFORMWHENEVERPRACTICAL,SOTHEREAREDOZENSOFOTHEREXAMPLESOFMORECOMPLEXLAYOUTSFORYOUTOPERUSEFROMCHAPTER7ONWARDWHATSWITHTHESIGNSMANYWIDGETSANDCONTAINERSONLYNEEDTOAPPEARINTHEXMLLAYOUTFILEANDDONOTNEEDTOBEREFERENCEDINYOURJAVACODEFOREXAMPLE,ASTATICLABELTEXTVIEWFREQUENTLYONLYNEEDSTOBEINTHELAYOUTFILETOINDICATEWHEREITSHOULDAPPEARTHESESORTSOFELEMENTSINTHEXMLFILEDONOTNEEDTOHAVETHEANDROIDIDATTRIBUTETOGIVETHEMANAMEANYTHINGYOUDOWANTTOUSEINYOURJAVASOURCE,THOUGH,NEEDSANANDROIDIDTHECONVENTIONISTOUSEID/ASTHEIDVALUE,WHERETHEREPRESENTSYOURLOCALLYUNIQUENAMEFORTHEWIDGETINQUESTIONINTHEXMLLAYOUTEXAMPLEINTHEPRECEDINGSECTION,ID/BUTTONISTHEIDENTIFIERFORTHEBUTTONWIDGETANDROIDPROVIDESAFEWSPECIALANDROIDIDVALUES,OFTHEFORMANDROIDID/WEWILLSEESOMEOFTHESEINVARIOUSCHAPTERSOFTHISBOOK,SUCHASCHAPTERS8AND10WEATTACHTHESETOTHEJAVAHOWGIVENTHATYOUHAVEPAINSTAKINGLYSETUPTHEWIDGETSANDCONTAINERSINANXMLLAYOUTFILENAMEDMAINXMLSTOREDINRES/LAYOUT,ALLYOUNEEDISONESTATEMENTINYOURACTIVITYSONCREATECALLBACKTOUSETHATLAYOUTSETCONTENTVIEWRLAYOUTMAINTHISISTHESAMESETCONTENTVIEWWEUSEDEARLIER,PASSINGITANINSTANCEOFAVIEWSUBCLASSINTHATCASE,ABUTTONTHEANDROIDBUILTVIEW,CONSTRUCTEDFROMOURLAYOUT,ISACCESSEDFROMTHATCODEGENERATEDRCLASSALLOFTHELAYOUTSAREACCESSIBLEUNDERRLAYOUT,KEYEDBYTHEBASENAMEOFTHELAYOUTFILEMAINXMLRESULTSINRLAYOUTMAINTOACCESSOURIDENTIFIEDWIDGETS,USEFINDVIEWBYID,PASSINGINTHENUMERICIDENTIFIEROFTHEWIDGETINQUESTIONTHATNUMERICIDENTIFIERWASGENERATEDBYANDROIDINTHERCLASSASRIDSOMETHINGWHERESOMETHINGISTHESPECIFICWIDGETYOUARESEEKINGTHOSEWIDGETSARESIMPLYSUBCLASSESOFVIEW,JUSTLIKETHEBUTTONINSTANCEWECREATEDINCHAPTER4THERESTOFTHESTORYINTHEORIGINALNOWDEMO,THEBUTTONSFACEWOULDSHOWTHECURRENTTIME,WHICHWOULDREFLECTWHENTHEBUTTONWASLASTPUSHEDORWHENTHEACTIVITYWASFIRSTSHOWN,IFTHEBUTTONHADNOTYETBEENPUSHEDMOSTOFTHATLOGICSTILLWORKS,EVENINTHISREVISEDDEMONOWREDUXHOWEVER,RATHERTHANINSTANTIATINGTHEBUTTONINOURACTIVITYSONCREATECALLBACK,WECANREFERENCETHEONEFROMTHEXMLLAYOUTPACKAGECOMCOMMONSWAREANDROIDLAYOUTSIMPORTANDROIDAPPACTIVITYIMPORTANDROIDOSBUNDLEIMPORTANDROIDVIEWVIEWIMPORTANDROIDWIDGETBUTTONIMPORTJAVAUTILDATEPUBLICCLASSNOWREDUXEXTENDSACTIVITYIMPLEMENTSVIEWONCLICKLISTENERBUTTONBTNOVERRIDEPUBLICVOIDONCREATEBUNDLEICICLESUPERONCREATEICICLESETCONTENTVIEWRLAYOUTMAINBTNBUTTONFINDVIEWBYIDRIDBUTTONBTNSETONCLICKLISTENERTHISUPDATETIMEPUBLICVOIDONCLICKVIEWVIEWUPDATETIMEPRIVATEVOIDUPDATETIMEBTNSETTEXTNEWDATETOSTRINGTHEFIRSTDIFFERENCEISTHATRATHERTHANSETTINGTHECONTENTVIEWTOBEAVIEWWECREATEDINJAVACODE,WESETITTOREFERENCETHEXMLLAYOUTSETCONTENTVIEWRLAYOUTMAINTHERJAVASOURCEFILEWILLBEUPDATEDWHENWEREBUILDTHISPROJECTTOINCLUDEAREFERENCETOOURLAYOUTFILESTOREDASMAINXMLINOURPROJECTSRES/LAYOUTDIRECTORYTHEOTHERDIFFERENCEISTHATWENEEDTOGETOURHANDSONOURBUTTONINSTANCE,FORWHICHWEUSETHEFINDVIEWBYIDCALLSINCEWEIDENTIFIEDOURBUTTONASID/BUTTON,WECANREFERENCETHEBUTTONSIDENTIFIERASRIDBUTTONNOW,WITHTHEBUTTONINSTANCEINHAND,WECANSETTHECALLBACKANDSETTHELABELASNEEDEDASYOUCANSEEINFIGURE51,THERESULTSLOOKTHESAMEASWITHTHEORIGINALNOWDEMOFIGURE51THENOWREDUXSAMPLEACTIVITYEMPLOYINGBASICWIDGETSEVERYGUITOOLKITHASSOMEBASICWIDGETSFIELDS,LABELS,BUTTONS,ETCANDROIDSTOOLKITISNODIFFERENTINSCOPE,ANDTHEBASICWIDGETSWILLPROVIDEAGOODINTRODUCTIONASTOHOWWIDGETSWORKINANDROIDACTIVITIESASSIGNINGLABELSTHESIMPLESTWIDGETISTHELABEL,REFERREDTOINANDROIDASATEXTVIEWLIKEINMOSTGUITOOLKITS,LABELSAREBITSOFTEXTNOTEDITABLEDIRECTLYBYUSERSTYPICALLY,THEYAREUSEDTOIDENTIFYADJACENTWIDGETSEG,A“NAME”LABELBEFOREAFIELDWHEREONEFILLSINANAMEINJAVA,YOUCANCREATEALABELBYCREATINGATEXTVIEWINSTANCEMORECOMMONLY,THOUGH,YOUWILLCREATELABELSINXMLLAYOUTFILESBYADDINGATEXTVIEWELEMENTTOTHELAYOUT,WITHANANDROIDTEXTPROPERTYTOSETTHEVALUEOFTHELABELITSELFIFYOUNEEDTOSWAPLABELSBASEDONCERTAINCRITERIA,SUCHASINTERNATIONALIZATION,YOUMAYWISHTOUSEARESOURCEREFERENCEINTHEXMLINSTEAD,ASWILLBEDESCRIBEDINCHAPTER9TEXTVIEWHASNUMEROUSOTHERPROPERTIESOFRELEVANCEFORLABELS,SUCHASANDROIDTYPEFACETOSETTHETYPEFACETOUSEFORTHELABELEG,MONOSPACEANDROIDTEXTSTYLETOINDICATETHATTHETYPEFACESHOULDBEMADEBOLDBOLD,ITALICITALIC,ORBOLDANDITALICBOLD_ITALICANDROIDTEXTCOLORTOSETTHECOLOROFTHELABELSTEXT,INRGBHEXFORMATEG,FF0000FORREDFOREXAMPLE,INTHEBASIC/LABELPROJECT,YOUWILLFINDTHEFOLLOWINGLAYOUTFILEASYOUCANSEEINFIGURE61,JUSTTHATLAYOUTALONE,WITHTHESTUBJAVASOURCEPROVIDEDBYANDROIDSPROJECTBUILDEREG,ACTIVITYCREATOR,GIVESYOUTHEAPPLICATIONFIGURE61THELABELDEMOSAMPLEAPPLICATIONBUTTON,BUTTON,WHOSGOTTHEBUTTONWEVEALREADYSEENTHEUSEOFTHEBUTTONWIDGETINCHAPTERS4AND5ASITTURNSOUT,BUTTONISASUBCLASSOFTEXTVIEW,SOEVERYTHINGDISCUSSEDINTHEPRECEDINGSECTIONINTERMSOFFORMATTINGTHEFACEOFTHEBUTTONSTILLHOLDSFLEETINGIMAGESANDROIDHASTWOWIDGETSTOHELPYOUEMBEDIMAGESINYOURACTIVITIESIMAGEVIEWANDIMAGEBUTTONASTHENAMESSUGGEST,THEYAREIMAGEBASEDANALOGUESTOTEXTVIEWANDBUTTON,RESPECTIVELYEACHWIDGETTAKESANANDROIDSRCATTRIBUTEINANXMLLAYOUTTOSPECIFYWHATPICTURETOUSETHESEUSUALLYREFERENCEADRAWABLERESOURCE,DESCRIBEDINGREATERDETAILINTHECHAPTERONRESOURCESYOUCANALSOSETTHEIMAGECONTENTBASEDONAURIFROMACONTENTPROVIDERVIASETIMAGEURIIMAGEBUTTON,ASUBCLASSOFIMAGEVIEW,MIXESINTHESTANDARDBUTTONBEHAVIORS,FORRESPONDINGTOCLICKSANDWHATNOTFOREXAMPLE,TAKEAPEEKATTHEMAINXMLLAYOUTFROMTHEBASIC/IMAGEVIEWSAMPLEPROJECTWHICHISFOUNDALONGWITHALLOTHERCODESAMPLESATHTTP/APRESSCOMTHERESULT,JUSTUSINGTHECODEGENERATEDACTIVITY,ISSHOWNINFIGURE62FIGURE62THEIMAGEVIEWDEMOSAMPLEAPPLICATIONFIELDSOFGREENOROTHERCOLORSALONGWITHBUTTONSANDLABELS,FIELDSARETHETHIRD“ANCHOR”OFMOSTGUITOOLKITSINANDROID,THEYAREIMPLEMENTEDVIATHEEDITTEXTWIDGET,WHICHISASUBCLASSOFTHETEXTVIEWUSEDFORLABELSALONGWITHTHESTANDARDTEXTVIEWPROPERTIESEG,ANDROIDTEXTSTYLE,EDITTEXTHASMANYOTHERSTHATWILLBEUSEFULFORYOUINCONSTRUCTINGFIELDS,INCLUDINGANDROIDAUTOTEXT,TOCONTROLIFTHEFIELDSHOULDPROVIDEAUTOMATICSPELLINGASSISTANCEANDROIDCAPITALIZE,TOCONTROLIFTHEFIELDSHOULDAUTOMATICALLYCAPITALIZETHEFIRSTLETTEROFENTEREDTEXTEG,FIRSTNAME,CITYANDROIDDIGITS,TOCONFIGURETHEFIELDTOACCEPTONLYCERTAINDIGITSANDROIDSINGLELINE,TOCONTROLIFTHEFIELDISFORSINGLELINEINPUTORMULTIPLELINEINPUTEG,DOESMOVEYOUTOTHENEXTWIDGETORADDANEWLINEBEYONDTHOSE,YOUCANCONFIGUREFIELDSTOUSESPECIALIZEDINPUTMETHODS,SUCHASANDROIDNUMERICFORNUMERICONLYINPUT,ANDROIDPASSWORDFORSHROUDEDPASSWORDINPUT,ANDANDROIDPHONENUMBERFORENTERINGINPHONENUMBERSIFYOUWANTTOCREATEYOUROWNINPUTMETHODSCHEMEEG,POSTALCODES,SOCIALSECURITYNUMBERS,YOUNEEDTOCREATEYOUROWNIMPLEMENTATIONOFTHEINPUTMETHODINTERFACE,THENCONFIGURETHEFIELDTOUSEITVIAANDROIDINPUTMETHODFOREXAMPLE,FROMTHEBASIC/FIELDPROJECT,HEREISANXMLLAYOUTFILESHOWINGANEDITTEXTNOTETHATANDROIDSINGLELINEISFALSE,SOUSERSWILLBEABLETOENTERINSEVERALLINESOFTEXTFORTHISPROJECT,THEFIELDDEMOJAVAFILEPOPULATESTHEINPUTFIELDWITHSOMEPROSEPACKAGECOMCOMMONSWAREANDROIDBASICIMPORTANDROIDAPPACTIVITYIMPORTANDROIDOSBUNDLEIMPORTANDROIDWIDGETEDITTEXTPUBLICCLASSFIELDDEMOEXTENDSACTIVITYOVERRIDEPUBLICVOIDONCREATEBUNDLEICICLESUPERONCREATEICICLESETCONTENTVIEWRLAYOUTMAINEDITTEXTFLDEDITTEXTFINDVIEWBYIDRIDFIELDFLDSETTEXT“LICENSEDUNDERTHEAPACHELICENSE,VERSION20“THE“LICENSE“YOUMAYNOTUSETHISFILE“EXCEPTINCOMPLIANCEWITHTHELICENSEYOUMAY“OBTAINACOPYOFTHELICENSEAT“HTTP/WWWAPACHEORG/LICENSES/LICENSE20“THERESULT,ONCEBUILTANDINSTALLEDINTOTHEEMULATOR,ISSHOWNINFIGURE63FIGURE63THEFIELDDEMOSAMPLEAPPLICATIONNOTEANDROIDSEMULATORONLYALLOWSONEAPPLICATIONINTHELAUNCHERPERUNIQUEJAVAPACKAGESINCEALLTHEDEMOSINTHISCHAPTERSHARETHECOMCOMMONSWAREANDROIDBASICPACKAGE,YOUWILLONLYSEEONEOFTHESEDEMOSINYOUREMULATORSLAUNCHERATANYONETIMEANOTHERFLAVOROFFIELDISONETHATOFFERSAUTOCOMPLETION,TOHELPUSERSSUPPLYAVALUEWITHOUTTYPINGINTHEWHOLETEXTTHATISPROVIDEDINANDROIDASTHEAUTOCOMPLETETEXTVIEWWIDGETANDISDISCUSSEDINCHAPTER8JUSTANOTHERBOXTOCHECKTHECLASSICCHECKBOXHASTWOSTATESCHECKEDANDUNCHECKEDCLICKINGTHECHECKBOXTOGGLESBETWEENTHOSESTATESTOINDICATEACHOICEEG,“ADDRUSHDELIVERYTOMYORDER”INANDROID,THEREISACHECKBOXWIDGETTOMEETTHISNEEDITHASTEXTVIEWASANANCESTOR,SOYOUCANUSETEXTVIEWPROPERTIESLIKEANDROIDTEXTCOLORTOFORMATTHEWIDGETWITHINJAVA,YOUCANINVOKEISCHECKEDTODETERMINEIFTHECHECKBOXHASBEENCHECKEDSETCHECKEDTOFORCETHECHECKBOXINTOACHECKEDORUNCHECKEDSTATETOGGLETOTOGGLETHECHECKBOXASIFTHEUSERCHECKEDITALSO,YOUCANREGISTERALISTENEROBJECTINTHISCASE,ANINSTANCEOFONCHECKEDCHANGELISTENERTOBENOTIFIEDWHENTHESTATEOFTHECHECKBOXCHANGESFOREXAMPLE,FROMTHEBASIC/CHECKBOXPROJECT,HEREISASIMPLECHECKBOXLAYOUTTHECORRESPONDINGCHECKBOXDEMOJAVARETRIEVESANDCONFIGURESTHEBEHAVIOROFTHECHECKBOXPUBLICCLASSCHECKBOXDEMOEXTENDSACTIVITYIMPLEMENTSCOMPOUNDBUTTONONCHECKEDCHANGELISTENERCHECKBOXCBOVERRIDEPUBLICVOIDONCREATEBUNDLEICICLESUPERONCREATEICICLESETCONTENTVIEWRLAYOUTMAINCBCHECKBOXFINDVIEWBYIDRIDCHECKCBSETONCHECKEDCHANGELISTENERTHISPUBLICVOIDONCHECKEDCHANGEDCOMPOUNDBUTTONBUTTONVIEW,BOOLEANISCHECKEDIFISCHECKEDCBSETTEXT“THISCHECKBOXISCHECKED“ELSECBSETTEXT“THISCHECKBOXISUNCHECKED“NOTETHATTHEACTIVITYSERVESASITSOWNLISTENERFORCHECKBOXSTATECHANGESSINCEITIMPLEMENTSTHEONCHECKEDCHANGELISTENERINTERFACEVIACBSETONCHECKEDCHANGELISTENERTHISTHECALLBACKFORTHELISTENERISONCHECKEDCHANGED,WHICHRECEIVESTHECHECKBOXWHOSESTATEHASCHANGEDANDWHATTHENEWSTATEISINTHISCASE,WEUPDATETHETEXTOFTHECHECKBOXTOREFLECTWHATTHEACTUALBOXCONTAINSTHERESULTCLICKINGTHECHECKBOXIMMEDIATELYUPDATESITSTEXT,ASYOUCANSEEINFIGURES64AND65FIGURE64THECHECKBOXDEMOSAMPLEAPPLICATION,WITHTHECHECKBOXUNCHECKEDFIGURE65THESAMEAPPLICATION,NOWWITHTHECHECKBOXCHECKEDTURNTHERADIOUPASWITHOTHERIMPLEMENTATIONSOFRADIOBUTTONSINOTHERTOOLKITS,ANDROIDSRADIOBUTTONSARETWOSTATE,LIKECHECKBOXES,BUTCANBEGROUPEDSUCHTHATONLYONERADIOBUTTONINTHEGROUPCANBECHECKEDATANYTIMELIKECHECKBOX,RADIOBUTTONINHERITSFROMCOMPOUNDBUTTON,WHICHINTURNINHERITSFROMTEXTVIEWHENCE,ALLTHESTANDARDTEXTVIEWPROPERTIESFORFONTFACE,STYLE,COLOR,ETC,AREAVAILABLEFORCONTROLLINGTHELOOKOFRADIOBUTTONSSIMILARLY,YOUCANCALLISCHECKEDONARADIOBUTTONTOSEEIFITISSELECTED,TOGGLETOSELECTIT,ANDSOON,LIKEYOUCANWITHACHECKBOXMOSTTIMES,YOUWILLWANTTOPUTYOURRADIOBUTTONWIDGETSINSIDEOFARADIOGROUPTHERADIOGROUPINDICATESASETOFRADIOBUTTONSWHOSESTATEISTIED,MEANINGONLYONEBUTTONOUTOFTHEGROUPCANBESELECTEDATANYTIMEIFYOUASSIGNANANDROIDIDTOYOURRADIOGROUPINYOURXMLLAYOUT,YOUCANACCESSTHEGROUPFROMYOURJAVACODEANDINVOKECHECKTOCHECKASPECIFICRADIOBUTTONVIAITSIDEG,GROUPCHECKRIDRADIO1CLEARCHECKTOCLEARALLRADIOBUTTONS,SONONEINTHEGROUPARECHECKEDGETCHECKEDRADIOBUTTONIDTOGETTHEIDOFTHECURRENTLYCHECKEDRADIOBUTTONOR1IFNONEARECHECKEDFOREXAMPLE,FROMTHEBASIC/RADIOBUTTONSAMPLEAPPLICATION,HEREISANXMLLAYOUTSHOWINGARADIOGROUPWRAPPINGASETOFRADIOBUTTONWIDGETSFIGURE66SHOWSTHERESULTUSINGTHESTOCKANDROIDGENERATEDJAVAFORTHEPROJECTANDTHISLAYOUTFIGURE66THERADIOBUTTONDEMOSAMPLEAPPLICATIONNOTETHATTHERADIOBUTTONGROUPISINITIALLYSETTOBECOMPLETELYUNCHECKEDATTHEOUTSETTOPRESETONEOFTHERADIOBUTTONSTOBECHECKED,USEEITHERSETCHECKEDONTHERADIOBUTTONORCHECKONTHERADIOGROUPFROMWITHINYOURONCREATECALLBACKINYOURACTIVITYITSQUITEAVIEWALLWIDGETS,INCLUDINGTHEONESPREVIOUSLYSHOWN,EXTENDVIEW,ANDASSUCHGIVEALLWIDGETSANARRAYOFUSEFULPROPERTIESANDMETHODSBEYONDTHOSEALREADYDESCRIBEDUSEFULPROPERTIESSOMEOFTHEPROPERTIESONVIEWMOSTLIKELYTOBEUSEDINCLUDECONTROLSTHEFOCUSSEQUENCEANDROIDNEXTFOCUSDOWNANDROIDNEXTFOCUSLE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