android ui基础教程

AndroidUlFundamentals:Developanddesign PeachpitPress 1249EighthStreet 510/524-2178 510/524-2221(fax) FindusontheWebatwww.peachpit.com Toreporterrorspleasesendanotetoerrata@peachpit.com PeachpitPressisadivisionofPearsoneducation opyrightC2012byJasonOstrander Editor:CliffordColby Developmenteditor:RobynThomas navlado Technicaleditor:JasonLebrun raiger nteriordesign:MimiHeft Compositor:DanielleFoster Indexer:ValerieHaynesPerry Noticeofrights Allrightsreserved.Nopartofthisbookmaybereproducedortransmittedinanyformbyanymeans, electronic,mechanical,photocopying,recording,orotherwise,withoutthepriorwrittenpermissionofthe publisherForinformationongettingpermissionforreprintsandexcerptscontactpermissions@peachpit.com Noticeofliabilit Theinformationinthisbookisdistributedonan"AsIs"basiswithoutwarranty.Whileeveryprecautionhas beentakeninthepreparationofthebook,neithertheauthornorPeachpitshallhaveanyliabilitytoany personorentitywithrespecttoanylossordamagecausedorallegedtobecauseddirectlyorindirectlyby theinstructionscontainedinthisbookorbythecomputersoftwareandhardwareproductsdescribedinit Trademarks AndroidisatrademarkofGoogleInc,registeredintheUnitedStatesandothercountries.Manyofthe designationsusedbymanufacturersandsellerstodistinguishtheirproductsareclaimedastrademarks Wherethosedesignationsappearinthisbook,andPeachpitwasawareofatrademarkclaim,thedesigna tionsappearasrequestedbytheownerofthetrademark.Allotherproductnamesandservicesidentified throughoutthisbookareusedineditorialfashiononlyandforthebeneftofsuchcompanieswithno intentionofinfringementofthetrademark.Nosuchuse,ortheuseofanytradename,isintendedto conveyendorsementorotheraffiliationwiththisbook ISBN13:978-0-321-81458-6 ISBN10 0-321-81458-4 987654321 Printedandboundintheunitedstatesofamerica mylovelywife,St whotirelesslysupportsmeinallofmyadventures ACKNOWLEDGMENTS icouldwriteanentirebookthankingpeoplefortheirhelpalongtheway.Instead, I'llhavetosettleforthisshortparagraph ThankstoChrisH.forpushingmetoconsiderwritingabookandgivingme endlessencouragementandsupportToCliffCforgivingmethechancetowrite thisbook.ToRobynTforkeepingmeonscheduledespitemybestefforts.To JBLforfixingmycodeandrockingameanbassguitar.ToScoutFandMyrnav. forworkingtirelesslywhenIwaslategettingchapterstothem.ToLucasDand RobSforreadingearlychaptersandgivingmevaluablefeedback.Totheentire teamatdoubletwistfortheirdedicationtomakinggreatandroidsoftware.To theandroidteamatGoogleforcreatingagreatplatform.Tomyfamilyfortheir continuingsupportdespitemydroppingoffthefaceoftheearthToPeachpitfor givingmetheopportunitytowritethisforyou.Andtoyou,thereader,forgiving methechancetoteachyouinwhateversmallwayIcan JasonOstranderisawebandmobilesoftwaredeveloperworkingatSiliconValley startupdoubleTwist,wherehemakessyncingmediatoandroidphonessimple Priortothat,hesolvednetworkingproblemsatenergymanagementstartup SentillaanddefensecompanyNorthropGrumman.JasonholdsanMSinelectrical engineeringfromUCLA.HeliveswithhiswifeinSanFrancisco'sMissionDistrict wherehespendshistimesearchingfortheperfectchilerelle IVANDROIDUIFUNDAMENTALS:DEVELOPANDDESIGN CONTENTS Introduction Welcometoandroid PART1BASICANDROIDUI CHAPTER1GETTINGSTARTED BasicStructureofanAndroidapp Androiduibasics 14 Tools 22 1gU1 32 CHAPTER2CREATINGYOURFIRSTAPPLICATION ...34 CreatinganApp 36 GettingStartedwithAndroidviews ArrangingViews 41 Displayingalist 52 UnderstandingActivities 57 PreventingANRs 64 FinishingtheTimeTrackerApp WrappingUp CHAPTER3GOINGFURTHER.......................74 SupportingMultipleScreenSizes Handlingnotifications 84 Handlingevents Creatingmenus 96 ImplementingtheTimeTracker 102 ppingup 107 CONTENTsV PART2THEVIEWFRAMEWORK CHAPTER4 BASICVIEWS ...,110 CreatingaBasicform 112 DisplayingImage CreatingMapsandDisplayingWebsite 130 WrappingUp 136 CHAPTER5REUSABLEUI.........................138 AbstractingYourlayouts 140 AbstractingStylesandThemes UsingFragments Wrappingup CHAPTER6NAVIGATIONANDDATALOADING .164 IntroducingtheActionBar 166 NavigatingYourApp 172 LoadingdataintoViews 181 appingup 186 CHAPTER7ANDROIDWIDGETS 188 CreatingaBasicwidget 190 CreatingaCollectionWidget Wrappingup VIANDROIDUIFUNDAMENTALS:DEVELOPANDDESIGN PaRT3ADVANCEDUIDEVELOPMENT CHAPTERHANDLINGGESTUres ..214 ListeningtoTouchEvents 216 RespondingtoGestures 224 pping 229 CHAPTER9ANIMATION.......... ..230 Creatingdrawableanimations 232 Creatingviewanimations 235 CreatingPropertyanimations 246 WrappingUp CHAPTER10CREATINGCUSTOMVIEWS .256 UnderstandingHowandroidDrawsviews CreatingaCustomView 259 AddingCustomAttributestoYourCustomviews 267 CreatingCompoundComponents 2 WrappingUp 279 CHAPTER11CREATINGADVANCEDGRAPHICS 280 USingcanvas 282 UsingRenderScript USingOpenGL 294 WrappingUp 3O1 CHAPTER12LOCALIZATIONANDACCESSIBILITY302 MakingYourAppAvailableinMultipleLanguages 304 MakingYourAppaccessible 309 WrappingUp 315 316 CoNTENTsVII INTRODUCTION Thereisarevolutionhappeninginthetechnologyindustry.Touchscreeninterfaces combinedwithlow-costandubiquitoussmartphones,havecreatedaperfectstorm fordisruptiveinnovation.androidisattheforefrontofthischangebringingafree andopen-sourceplatformonwhichdeveloperscancreatethenextgenerationof applications.Withfreedevelopmenttoolsandanopenmarket,anyonecandevelop applicationsthatreachaworldwidemarket.Butwhychoosetodevelopforandroid? AndroidnowrunsonthemajorityofsmartphonesintheUnitedStatesAnd it'squicklyexpandingintonewmarketsanddevicetypes.Thelastyearhasseen theintroductionofhundredsofAndroid-basedtablets,includingthehitKindle Fire.GooglehasportedandroidtoTVswithitsGoogleTVplatform,andmany manufacturersarebeginningtoshipTVswithAndroidbuiltin.Boeinghasselected AndroidastheentertainmentplatformforitsnewDreamlinerjetFordisintegrat- ingAndroidintoitsin-dashSYNCentertainmentsystem.AndAndroidisquickly gainingtractioninthedevelopingworld,especiallyinAfrica,wheretheneedfor low-costhandsetsisgreatest Yetforalloftheplatformspromisethemajorityofandroidapplicationsstill lackthevisualpolishoftheirioScounterparts.Thisbookaimstoaddressthat issuebyprovidingdeveloperswithasolidfoundationforbuildingappUIs.Itwill coverthebasicsofuidevelopmentonAndroid,teachbestpracticesforcreating flexiblelayouts,andgiveyoutipsonhowtooptimizeyourUIforsmooth,fluid performance.icreatedthisbookinthehopethatitwillhelpdeveloperstocreate beautifulapplications WhoamI?I'vebeendevelopingsoftwareprofessionallyforalmosttenyears andI'vefocusedonembeddedandmobilesoftwareforthelastfive.Inmydayjob Iworkforoneofthetopandroiddevelopmentcompaniesandwritecodethat millionsofpeopleuseeveryday Androiddevelopmentcanbedifficultattimes,andthechallengesofsupporting suchadiversityofdevicescanbedaunting.Butwithagoodidea,asolidunder standingoftheframework,andalittlepersistence,anyonecancreateagreatapp thatisusedbymillionsofpeople ihopeyou'llenjoyreadingthisbookasmuchasienjoyedwritingitforyou VIlANDROidUIFUNDAMENTALS:DEVELOPANDDESIGN WHOTHISBOOKISFOR ThisbookisaimedatbeginningAndroiddeveloperswhoareinterestedincreating greatuserinterfaces.YouareexpectedtoknowbasicJavaprogrammingandXML syntax.ThefocusofthisbookisonUI.Whileyoudontneedtohaveexperience writingAndroidsoftware,manybasicandroidconceptsareonlydescribedin passing.Itwillhelpyoutohavearudimentaryknowledgeofandroiddevelopment WHOTHISBOOKISNOTFOR Thisbookisnotageneralintroductiontoprogrammingforandroid.whileitis intendedforbeginningAndroiddevelopers,thefocusisonuserinterfacetools andprogramming.Inparticular,thisbookwillnotcoverbasicAndroidconcepts suchasintents,services,orcontentproviders.Further,thisbookwillnotbean introductiontotheJavaprogramminglanguageortoXML.Youshouldknowhow toprogramandhowtoreadXML HOWYOUWILLLEARN Throughoutthisbook,you'lllearnbycreatinganactualapp,asimpletime tracker.Eachchapterincludesdetailedexamplesofrealandroidcodethatyou willcompileandrun.allcodeforthebookcanbefoundatthebook'swebsite www.peachpit.com/androiduifundamentals WHATYOUWILLLEARN You'lllearnhowtocreateuserinterfacesforAndroidapplicationsFromthemost basicconcepts,likeactivitiesandviews,allthewaytoadvancedgraphicsusing Renderscript,thisbookcoverseverythingyouwillusetobuildtheuserinterface ofyourapps ANOTEABOUTANDROIDVERSIONS ThisbookwaswrittentoAndroidversion4APIsandbestpractices,butitiscom patiblebacktoandroidversion2.2.Whenrelevant,notesandtipsareincludedto indicatewhenanaPiisdeprecatedornolongerappropriate.Theandroidcom patibilitylibrary,apackageofclassesthatback-portseveralnewerfeatures,will beusedthroughoutthebook INTRODUCTIONX