IOS 8 Programming - With Swift a Step by Step Guide Book for Beginners

iOS8ProgrammingwithSwift

AStepByStepGuideBookforBeginners.CreateYourOwnAppinOneDay!

KevinLyn.

Copyright2015byKevinLyn.

All rights reserved. No part of this publication may be reproduced, distributed, or

transmitted in any form or by any means, including photocopying, recording, or other

electronic or mechanical methods, without the prior written permission of the author,

except in the case of brief quotations embodied in critical reviews and certain other

noncommercialusespermittedbycopyrightlaw.

Disclaimer

While all attemptshavebeenmade toverify the informationprovided in this book, theauthordoesntassumeanyresponsibilityforerrors,omissions,orcontraryinterpretationsof the subjectmatter containedwithin.The information provided in this book is foreducationalandentertainmentpurposesonly.Thereaderisresponsibleforhisorherownactionsandtheauthordoesnotacceptanyresponsibilitiesforanyliabilitiesordamages,realorperceived,resultingfromtheuseofthisinformation.

Contents

BookDescription

Introduction

Chapter1:Definition

Chapter2:GettingStartedwithiOS8SwiftProgramming

Chapter3:VariablesandConstantsinSwift

Chapter4:TypeAnnotations

Chapter5:TuplesinSwift

Chapter6:EnumerationsinSwift

RawValues

Chapter7:UIAlertViewinSwift

Chapter8:NSTimerinSwift

ProjectSetup

CodingtheTimer

StoppingtheNSTimer

ClearingtheNSTimer

Chapter9:SwiftandPHP

PostingfromSwifttoPHP

HowtoGettheStatusoftheHTTPCode

Chapter10:ConnectingtoiTunesSearchAPI

HowtoConnecttheUserInterface

HowtoMaketheAPIRequest

HowtoPreparefortheResponse

HowtoUpdatetheTableViewUI

Chapter11:ImageLoadingandCachingAsynchronously

Chapter12:UsingObjective-CclassesinSwift

Chapter13:AnimationsinSwift

ContainerViewTransitions

Chapter14:CreatinganAudioPlayerwithSwift

CreatingtheUserInterface

ActionMethods

CreationandInitializationofAVAudioPlayerObject

ImplementationoftheAVAudioPlayerDelegateProtocolMethods

Conclusion

BookDescription

ThisbookbeginsbyexplainingtheiOS8andtheSwiftprogramminglanguage,including

theiroriginandfunctionality.ExplanationonhowtogetstartedwithSwiftisavailable,

includingsettinguptheenvironment.

Variables,constants,andTupleswhichareusedtostorevaluesinSwifthavebeen

explored.Onreadingthisbook,youwillgettounderstandhowtocreateanNSTimerfor

youriOSapp.EnumerationsandTypeannotationsinSwifthavealsobeenexploredin

detail.YouwillgettounderstandhowtosendsomepostrequesttoaPHPscript,usinga

server.YouwillalsoknowhowtoloadimagesintoyourSwiftappasynchronously.

ConnectingyourapptotheiTunesSearchAPIisalsoexamined.Theprocessofimporting

Objective-CclassesintoSwifthasbeenexplained.AnimationsandplayingaudioinSwift

havealsobeendiscussed.Programsillustratinghowtoachievetheabovefeatureshave

beenincluded,aswellaspicturesillustratingthesame.

Thelanguageusedinthisbookisverysimple,sothatitsuitsboththeexpertsandthe

beginners.Thefollowingtopicshavebeendiscussed:

Definition

GettingStartedwithSwift

VariablesandConstants.

TypeAnnotations

Tuples

Enumerations

UIAlertView

NSTimerinSwift

SwiftandPHP

ConnectingtoiTunesSearchAPI

ImageLoadingandCachingAsynchronously

UsingObjective-CClasses

Animations

CreatinganAudioPlayer

Introduction

iOS8hasshownimprovedsupportforamazingfeatureswhichwerenotsupportediniOS

7.ThisexplainstheneedforthecreationofiOS8apps,andthereforetheneedtolearn

Swift.

Recently,AppleIncreleasediOS8intothemarket.ThisfollowedareleaseoftheSwift

programminglanguageforthepurposeofcreatingappstorunondevicessupportingthis

versionofiOS.Thislanguagehasshownanumberofimprovementsintermsof

functionalitycomparedtotheObjective-Cprogramminglanguage.

Chapter1:

Definition

iOSisanoperatingsystemusedonAppledevices.ItwasdevelopedbyAppleInc.inthe

year2007torunontheiPhone.Itwaslateradvancedtorunonotherdevicessuchasthe

iPadMini,iPodTouch,AppleTV,andiPad.TheinterfaceofiOSismadeofcontrolssuch

asbuttons,sliders,andswitches.

Theuserinterfacereliesondirectmanipulation.UsersinteractwiththeOSthrough

tapping,swiping,pinching,andreversepinching.iOS8wasdevelopedasasuccessorto

iOS7,anditistheeighthversionoftheoperatingsystem.Itwasreleasedintheyear

2014.

ItmadeseveralimprovementsonwhatwasprovidedbyiOS7intermsoffunctionality

anduserinterface.SomeofthechangesbroughtaboutbyiOS8includedanadvanced

photosapp,notificationcenter,HealthKit,andHomeKit.Forinstance,withtheiOS8

photoapp,usershavemoreeditingcapabilitiesfortheirphotosastheycansetthe

brightnessandcolortotheirchoice.Thephotoscanalsoberotatedineitheraclockwiseor

anti-clockwisedirection.ThesefeatureswerenotavailableiniOS7.

TheNotificationCenteriniOS8hasonlytwotabs,thatis,theTodayand

Notificationstabs.IniOS7,thishadthreetabs.Userscannoweditthecomponentsof

thenotificationcenterbytheadditionofwidgets,andreplyingtomessagesfromthe

NotificationCenterisnowpossible.

Themessagingapphasalsobeenimproved,sinceuserscannowsendmessagesincluding

videosandaudios,aswellassetthemessagestobedeletedafteraperiodofchoice.This

showsthatiOS8hasbroughtwithitanumberofadvancementsiniOS.Devicesrunning

iOS8havehitthemarket.iOS8appshavealsoshownalargenumberofdownloads,and

thisindicatesapositivegrowthinthefuture.

Chapter2:

GettingStartedwithiOS8Swiftprogramming

SwiftisthenewprogramminglanguageintroducedbyAppletoslowlyreplaceObjective-

C.ItoffersadvancedfeatureswhicharenotavailableintheObjective-Cprogramming

language.InSwift,programmerscancombineObjective-C++,Objective-C,andSwiftin

justasingleprogramsoastotakeadvantageofthefeaturesfromthethreelanguages,

meaningthatonecancreatecoolandamazingappswiththislanguage.

HelloWorldApp

BeforecreatingourHelloWorldapp,downloadthebetaversionofXcode6.Youcanget

thisfromtheiOSdevelopercenter.Onceyougetthrough,createanewprojectbyclicking

on:

File->New->NewProject.Awidowwillappearwithsomeoptionsforyoutochoose.

SelectSingleviewApplication.

Givetheprojectanameofchoice.SelectthelanguagefollowedbychoosingSwift.

Chooseadirectorytostoreyourproject.Itwillbeoverandreadytogo.Notethatinthere

Swiftprogramminglanguage,therearenoheadersandwhateveriscodedgoestothe

.Swiftfile.

Twotemplatefilesarealsocreated,thatis,ViewController.swiftandAppController.swift.

Ifyouruntheappatthistime,yougetanemptyview,sowaituntilwedevelopsomeUI

controls.NoticethatafteryouopentheStoryboard,theviewcontrollerwillhavea

differentsize,neitherthatoftheiPadnortheiPhone.

Startbydraggingalabel,followedbytextfield,andfinallyabutton.Alignthemtomake

surethattheyareinthepositionthatyouwant.

Itisnowtimetocreatetheoutlets.JuststartbyselectingtheLabel,holddowntheCtrl

key,andthendragittothefileontherightwindow.Thiswillformthe

ViewController.swiftfile.Repeatthisforthreecontrolssothatyoucanhavethreeoutlets.

Thethreeoutletswillbeasfollows:

@IBOutletvarhelloLabel:UILabel

@IBOutletvarnameTextField:UITextField

@IBOutletvarhelloButton:UIButton

IfyouaregoodatprogrammingwithObjective-C,youwillnoticesomesimilaritieswith

Swift,suchtheIBOutletkeyword.However,thereisanewkeywordoverride.This

keywordwillbeusedincaseyouoverrideamethodinthesuperclass.Swifthasbrought

aboutthepreventionofcommonmistakesthatprogrammersmakesincewiththis

keyword,overridingmethodswithoutrealizingitwillnotbepossible.

Wethenneedtodeclareamethodtohelpinsettinguptheuserinterface.Thismethodwill

beasfollows:

funccreateUI(){

}

NoticethesyntaxofdeclaringamethodinSwift.Themethodhasnoargumentsandit

returnsnothing.OuraimistodisplayaredtextatthecenterofthelabelwrittenHello

World.Thecodebelowwillachievethis:

helloLabel.text=HelloSwift!

helloLabel.textColor=UIColor.redColor()

helloLabel.textAlignment=NSTextAlignment.Center

Noticethatwehavenotusedsemicolonsattheendofthelines,northesymbol@before

stringliterals.Methodsforspecifyingcolorhavealsobeenspecifiedratherthansending

somemessagetoUIcolor.Forthepurposeofguidingtheuser,letusaddaplaceholderto

thetextfield:

nameTextField.placeholder=Enteryourname

Tochangethetextdisplayedonthebutton:

helloButton.setTitle(sayHello,forState:.Normal)

Nowwearedonewithcreatingtheuserinterface.Itstimetocallthemethodthatwe

createdearlieron.Thiscanbedoneasfollows:

overridefuncviewDidLoad(){

super.viewDidLoad()

//anyadditionalsetupcanbedonehereafterloadingtheview

createUI()

}

Wecannowrunourapp.However,letusaddsomefunctionalitytothebutton.Todothis,

justbringuptheassistanteditorwhileinInterfaceBuilder.Dragtotheviewcontroller

fromtheUIButtonbypressingtheCtrlkey.NamethemethodashelloAction.Thisshould

bedoneaftermovingtoactionfromoutlet.

Wewanttomakethelabeldisplaythetextenteredinthetextfield.Ifnothingwasentered

inthetextfield,analertdialogshouldbeshownpromptingtheusertoentersometext.

Thiscanbeachievedusingthecodebelow:

@IBActionfunchelloAction(sender:AnyObject){

letnm=nameTextField.text

ifnm.isEmpty{

letalertdialog=UIAlertController(title:Error,message:Enteryourname,

preferredStyle:UIAlertControllerStyle.Alert)

alertdialog.addAction(UIAlertAction(title:OK,style:UIAlertActionStyle.Default,

handler:nil))

self.presentViewController(alertdialog,animated:true,completion:nil)

}else{

helloLabel.text=Hello\(nm)!

}

}

First,wegotthetextfromthetextviewandstoreditinaconstantvariable.Constant

variablesarehighlyusefulinSwift.Wethencheckwhethertheconstantisemptyor

containssometext.Ifitisempty,weprovideanalertboxpromptingtheusertoenterhis

name.

Ifithassometext,thisnameiscombinedwiththewordHello,sotheoutputwillbe

Helloname,wherethenameisthetextthatyouenteredinthetextfield.Thishasreally

shedsomelighttoyouasfarasSwiftisconcerned.

Ifyouhavealittleprogrammingexperience,thelanguagewillbeeasyforyou.Notice

thatwehaveusedUIAlertControllerinsteadoftheUIAlertView.ThisisbecauseiniOS8,

thelattercaneasilycrashourapp,sowearetryingtoavoidthis.

YoucannowruntheapponaniPhonesimulator.UseiPhone5s.Thefollowingwillbethe

output:

Whenyouenteryournameonthetextfieldandpresstheenterkey,youwillobservea

changeintheredtext,sincetheSwiftwillchangetothenamethatyouhaveentered.

Thatisyourfirstapp,whichisveryamazing.

Chapter3:

VariablesandConstantsinSwift

YoumightneedtostoredataforyouriOS8app.Variablescanbeusedforthispurpose.In

Swift,valuescanbestoredeitherasavariableorasaconstant.Example:

varnumber=20

letresult=15

Thefirstexampleillustrateshowtostoreavalueasavariable,whereasthesecond

exampleillustrateshowtostoreavalueasaconstant.Notethekeywordswehaveusedto

defineaconstantandavariable.

Youhaverealizedthatwehavenotspecifiedthetypeforourvariableandconstantinthe

aboveexamples.ThereasonisbecauseSwifthasvalueswhichareimplicitlytypestored.

However,youcanalsochoosetospecifythetypeofthevalue.Thisismostlydonewhen

thereisnoinitialization.Swiftwillinferthatsince20isaninteger,theprogrammer

wantedtostoreaninteger,sotheresultmustalsobeaninteger.Totypeyourvalues,do

thefollowing:

varnumber:Double

Letconstantsmustalwaysbeinitialized.Thisshouldbethecaseevenifyouhave

explicitlytypedthem.Youmightwantadoubleaftertypinganintegervalueasshown

below:

letvalue:Double=30

Insteadofstoringthevalue30,itwillstore30.0.

Thevalueofaconstantcannotbechanged.Tryingtodosowillresultintoanerror:

letresult=15

result=22

Ifyouruntheprogramwiththeabove,thefollowingerrorwillbeseen:

Error:Cannotassigntoletvalueresult

Thismessagemeansthatthevaluecannotbechangedasitisaconstant,sodonttrythis

inSwift.

Chapter4:

TypeAnnotations

Sometimes,youarenotsurewhetherthespecifiedvalueandtheexpectedvaluematch.

ThisexplainstheneedfortypeannotationinSwift.Thiscanbeappliedwhenweare

declaringvariablesandfunctions.TheideabehindtypeannotationsinSwiftisveryeasy,

asyoujustspecifythekindofvariablethatshouldgointoyourconstantsandvariables.

SinceSwiftissafewhenitcomestotypes,youmustthenadheretothisbymakingsure

thatthetypethatyouassignavariableisthesameastheannotatedvariable.However,do

notbemuchintothisasSwiftcandothisforyou.

Example:

AssumingthatyouhaveavariablecalledstudentNameandyouraimistopassastring

intothisvariable,youcandothisasfollows:

varstudentName=John

SwiftwillautomaticallyknowfromthisthatthevariablestudentNameisastring.Letus

trytopassanintegertothesamevariable:

varstudentName=123

Oncewedothis,thefollowingerrormessagewillbeproduced:

TypeStringdoesnotconformtoprotocolIntegerLiteralConvertable.

ThismeansthatSwiftwillpassanintegervaluetoavariableexpectedtobeastring.So,

incaseyougetsuchanerror,justknowthatyouhaveaproblemwithtypeannotation.

Youmightneedtospecifyandcreateastringtypeannotationatthebeginningofyour

program.Thiscanalsobedoneinanotherfilewhichistobeincludedasfollows:

varstudentName:String;

IfyouassignastringtothevariablestudentNamelateroninthecodeasshownbelow,all

willbewell:

studentName=John

However,tryingtoassignanintegertothisvariableasshownbelowwillresultintoan

errormessage:

studentName=123

ThisshowshowtypeannotationsareveryusefulinSwift,andalsoveryeasyto

understandanduseincoding.

Chapter5:

TuplesinSwift

TheseareoneofthefeaturesofSwiftprogramminglanguage.Withthem,onecanstore

multiplevaluesinasinglevalue.Obviously,thesevaluesarecloselyrelatedtoeachother.

Example:

varstudent=(John,123,true)

AboveisanexampleofaTupleinSwift.WheneverSwiftmeets(),itknowsthatithas

metaTuple.ThevaluesinaTupleareseparatedusingacomma(,).Justlikewhathappens

inanarray,Tuplessupporttheuseofindices,wherebythefirstelementisatindex0.To

returntheelementsoftheaboveTuple,wecandothefollowing:

student.0//=John

student.1//=123

student.3//=true

Otherthantheabovemethod,wecanassignnamestotheelementsofaTuple.Thisis

shownbelow:

varstudent=(name:John,admission:123,isClubMember:true)

Afterdeclaring,youcangetthevaluesasfollows:

student.name//etc

IfyouwanttogetaTuplefromareturnsuchasafunction,youhavetodecomposethe

partsoftheTupleintovariablesasfollows:

var(name,admission,isClubMember)=student

Thevariablescanthenbetypeputasshownbelow:

1Name

2Admission

3isClubMember

Incaseyoudontwanttoassignavalue,justputanunderscoreinthefieldasshown

below:

var(_,name,_)

NowyouknowhowtouseTuplesinSwift.MakeuseofthemwhendevelopingiOS8

apps.Theyarequiteeasytolearnandunderstand,yetveryusefulinSwift.

Chapter6:

EnumerationsinSwift

Ifyouwanttodefineacommontypeforagroupofitemsorvalueswhicharerelated,then

enumerationwillhelpyoutodoso.Itsupportssomeofthefeatureswhichwere

traditionallysupportedbyclassesonly.Thesefeaturesincludeinstancemethodsand

computedproperties.Initialvaluesofmemberscanalsobedefinedbytheuseof

enumerations.

TheyhaveawiderangeofusesinSwiftprogramming,andthisexplainswhyyouneedto

understandhowtousethem.Mostprogrammersviewenumerationsascomplex,butin

realsense,theyarenot.

CreateanewSwiftplayground.InSwift,theyareusuallyreferredtoasenum,sodontget

confusedwhenyoufindthis.Letuscreateanenumthatwillshowthepossiblewaysto

exitfromahouse:

enumexitDoor{

caseDoor1

caseDoor2

caseDoor3

caseDoor4

}

Thevaluesinside{}(curlybraces)arecalledthemembervalues.Todefinethemember

valuesinanenum,weusethecasekeyword.Thisshowsthatanewlinefordefininga

memberoftheenumhasbeenstarted.Theenumabovewillcontainonlythelistedabove

asmembers.Otherthandefiningthemindividually,theycanbedefinedinasingleline,

andyouseparatethemwithacommaasfollows:

enumExitDoor{

caseDoor1,Door2,Door3,Door4

}

Noticethatthenameofeverymemberstartswithacapitalletter.Tousetheenumeration

above,wecandoasfollows:

VarjohnExitedThroughDoor=ExitedDoor.Door1

Noticethatwedeclaredavariableandassignedavaluetothesamevariableatthesame

time.Again,ifyouwerekeenonautoComplete,yourealizedthatitgavetheoptionsof

onlyfourdoors.Thisisoneofthewaysusedinenumstoensureaccuracy.

Apartfromthemethodmentionedabove,wecanalsousethisone:

varmaryExitedThroughDoor:ExitedDoor

maryExitedThroughDoor=.Door2

Itisveryclearthatfromthesecondmethod,wehaveusedspecificationsoastosetthe

value.Letusdemonstratetheuseofswitchstatementtoaccessthevaluesofanenum:

switchjohnExitedThroughDoor{

case.Door1:

println(HeusedDoor1)

case.Door2:


case.Door3:


case.Door4:

println(He4usedDoor)

}

TheoutputontheplaygroundwillshowthatDoor1wasused.Noticewehavespecifieda

caseforeverymemberoftheenum,asfailuretodosowillresultintoanerror.Youcan

deleteoneofthecasestatementsaboveandseewhatwillhappen.Thecompilerwilltell

thatyourcodehasaproblem.

EnumAssociatedValuesinSwift

Withassociatedvalues,extrainformationcanbeaddedtoeachvalueoftheenum.These

valuescanbeofanytype.Todemonstratethis,considertheenumshownbelow:

enumAssociationDemo{

caseName(String)

caseNums(Int,Int,Int)

}

Wehavedefinedtwocasestatements,onetoholdastringandtheotheronetoholdthree

valuesoftypeinteger.Letusdefinetwovariablesasshownbelow:

varname=AssociationDemo.Name(John)

varexampleNums=AssociationDemo.Nums(4,13,17)

Letustocheckthevaluesusingaswitchstatement:

switchname{

case.Name(letname):

println(Thenameis\(name))

case.Nums(letval1,letval2,letval3):

println(Thevalueofinteger1is\(val1))



}

Nowwehaveaccessedthevalues.Westartedbyaccessingthename,andthenlastlywe

accessedtheintegers.Everyvalueoftheenumhasbeenprovidedwithacase.

RawValues

Withrawvalues,youareabletodeclarevaluesinsidetheenum.Itworksjustinthe

oppositewayasassociatedvalues,sincetheseallowyoutodeclarevaluesoutsidean

enum.Thetypeofenumerationtousethetechniquemustbespecified.

enumEnum2:String{

caseName=John

caseWebSite=http://www.john.com

}

varname=Enum2.Name

varebsite:Enum2

website=.WebSite

Notethesyntaxwehaveusedtoaccessthevalues.Veryeasy.Youshouldknowhowto

handleenumswithoutvalues,asyoumighttrytoaccessemptyvalues.

//Nowletsaccessthosevaluesusingthehandy.Raw()

myName.toRaw()//OutputsPeter

myWebsite.toRaw()//Outputshttp://www.peterwitham.com

Chapter7:

UIAlertViewinSwift

AnalertviewcanberepresentedasfollowsusingiOS8SDKandSwift:

varalt=UIAlertController(title:TitleoftheAlert,message:Themessage

ofthealert,preferredStyle:UIAlertControllerStyle.Alert)

alt.addAction(UIAlertAction(title:OK,style:UIAlertActionStyle.Default,

handler:nil))

self.presentViewController(alt,animated:true,completion:nil)

ThestylecanalsobesettoeitherDestructiveorCancelifneeded.

Chapter8:

NSTimerinSwift

Ouraiminthischapteristocreateacounterapplication,anditwillmakeuseoftheSwift

NSTimerclass.ThisclasscanbeusedtocreateatimeriniOS8applications.Itfunctions

bywaitingforaspecificintervaloftimetoelapsesothatitcanfire.

Onceitfires,amessageisalwaystotheSwiftobjectwhichistargeted.Agoodexampleis

theschedulingofupdates,wherebythetimercanbeusedtotriggerthisataspecifictime.

Tocreatesuchanapp,theprojectneedstobesetupinaspecificmanner.

ProjectSetup

Createanewapplication(SingleView)andgiveitanameofyourchoice.Wethenneedto

addsomeelementstotheMain.storyboard.ThesewillbeobtainedfromtheobjectLibrary

inXcode.Theseelementsincludeanavigationbar,toolbar,UILabel,BarButton,Itemx2,

andaflexibleSpaceBarButtonItem.

AddingtheToolbar

Beginbydraggingthistotheprojectsbottom:

ClickontheItembuttonandgotothepropertyinspector.Chooseplay:

TheItemwillchangetoaplayicon,andthetoolbarwillbeasfollows:

AddingtheFlexibleSpaceBarButtonItem

Thepurposeofthisistospaceoutthebarbuttonitems.Ontopofthetoolbarlocatedat

theprojectsbottompart,dragthisitem:

Item1ofBarButton

Dragthistothebottomandleftofyourtoolbar.Itshouldlookasfollows:

NavigationBar

Ontopoftheviewcontroller,dragthenavigationbar.AvoidoverlappingtheiPhone

batterybynotplacingthenavigationbarrightatthetop.DoubleclickthewordTitle,

andrenameittosomethingelseofyourchoice.Inmycase,IwillrenameittoNSTimer

Tutorialsoitshouldlookasfollows:

Item2ofBarButton

Addanotherbarbuttononthenavigationbydraggingit.Placeittotheright.Doubleclick

ontheItemandchangeittoClear.

UILabel

Ontotheviewcontroller,dragthisitem.Placeitatthemiddleoftheproject.Fromthe

propertyinspector,editthelabelalignment,size,andcolor(optional).Doubleclickonthe

wordLabel,andchangeitto0(zero).

Theinterfaceisnowsetup.Thenextthingistostartcodingsoastoaddthenecessary

functionalitytothetimer.

Codingthetimer

SelectthefileViewController.swiftfromthenavigationareaoftheproject.Thisiswhere

codingshouldbedonetoaddfunctionalitytotheNSTimer.Todefinethetimer,weneed

todothisbetweenthefollowinglinesofcode:

classViewController:UIViewController{


WedefineourfirstvariabletmfortimerwhichisoftypeNSTimerasfollows:

vartm=NSTimer()

Abovethedeclarationabove,weshoulddefinethecounterandinitializeitto0asfollows:

varcounter=0

AtthemiddleofthestoryboardandontheUILabel,presstheCtrlkeyanddragtoyour

viewcontrollerfile.NameitCountingLabel.

ChecktheViewController.swiftfiletoseeifithasthefollowingcode:

@IBOutletvarcountingLabel:UILabel!

Repeatthesameprocedurefortheotherbuttons,butthistime,makesureyouchoosethe

connectiontypeAction.Afterdoingthat,thefollowingcodeshouldbeaddedtoyour

project:

@IBActionfuncstartButton(sender:AnyObject){}

@IBActionfuncpauseButton(sender:AnyObject){}

@IBActionfuncclearButton(sender:AnyObject){}

ValuescanthenbeaddedtotheCountingLabel.NotethattheUILabelisastring,whereas

thecounterisaninteger.Theoutputmustbeconvertedtoastringbeforeaddingittothe

label.Thiscanbedoneasfollows:

countingLabel.text=String(counter)

Itstimetostartthetimer.ThiscanbedonebyaddingthisfunctionalitytothestartButton

asfollows:

tm=NSTimer.scheduledTimerWithTimeInterval(TIME_INCREMENT,target:self,

selector:Selector(FUNCTION),userInfo:nil,repeats:BOOL)

Rememberthatwecreatedvariabletmearlieron,andwhatwedoneinthiscaseis

assigninganewinstanceofNSTimertothis.Notethatwehaveaddedsomenewthingsas

explainedbelow:

1.TIME_INCREMENT-specifiesthenumberofsecondsafterwhichthetimer

fires.Wewillsetthisoneto1.

2.FUNCTION-thisisafunctiontobecreated,anditwillbetriggeredwhen

thefiringtimeisreached.

3.BOOL-ifthevalueofthisissettoYES,itwillkeeponreschedulingitself

untilitisinvalidated.Afterfiring,thetimerwillbeinvalidatedifthisvalueissetto

NO.

Theabovelineofcodethenbecomes:

tm=NSTimer.scheduledTimerWithTimeInterval(1,target:self,selector:

Selector(counterUpdator),userInfo:nil,repeats:true)

Wehavedeclaredafunctionintheabovelineofcode.Weneedtocreateitanduseitfor

thepurposeofincrementingthevalueofthecounterby1.Assumingthatyouknowthe

incrementoperator,thatis,++,letususethis,anditwillincrementthisvalueby1.This

willhappeneverytimethisfunctioniscalled.Thiswillthenbecome:

FunccounterUpdator(){

countingLabel.text=String(counter++)

}

Youcannowrunyourapp.Onceyouclickonstart,youwillrealizehowmuchyouhave

achievedwithlesscoding.

StoppingtheNSTimer

ThemethodInvalidate()isusedtopauseorstoptheNSTimer.Weneedtoaddsome

functionalitytotheIBActionofthepausebuttonasshownbelow:

@IBActionfuncstopButton(sender:AnyObject){

tm.invalidate()

}

Nowyoucanplayaroundwiththetimerbystartingitandpausingit.

ClearingtheNSTimer

Forustoclearthecounter,thefollowingneedstobedone:

1.PausetheNSTimerfromfiring.

2.Resetthecountertonormal.

3.ClearthecountingLabel.

Notethattheaboveordermustbeadheredto,otherwisetheobjectivewillnotbeachieved.

ThefollowingshouldbetheappearanceoftheIBActionoftheclearButton:

@IBActionfuncclearButton(sender:AnyObject){

tm.invalidate()

counter=0

countingLabel.text=String(counter)

}

Youcannowrunyourapp.Everyfeaturethatwewantedhasworked,sowearedone.The

timerhasbeencreatedwithSwiftandNSTimer.ThisshowshowmuchSwiftcanbeused

todevelopamazingappsforiOS8devices.Moreso,usingintegersandstringsshouldnot

bea=nissuetoyounowasyouhavelearnedhowtousethem.

Chapter9:

SwiftandPHP

ItispossibletouseSwifttosendsomepostrequesttoaPHPscript.Thishappensona

server.IfyouconnectyourSwiftapptoaPHPwebservice,youwillachieve

functionalitiessuchasqueryingthedatabaseandevenregisteringtheusers.

Therearealsomanyfeaturesthatyoucanenjoy.Thereexistservicesthatcanhelpyouin

achievingthis.ProgrammerswithoutaccesstoaPHPwebserviceorthosewhocannot

createoneforthemselvescanusetheseservices.

Inthissection,wewilluseParse.comforthispurpose.ItusesHTTP(HyperTextTransfer

Protocol)requestcodestodeterminewhethertherequeststhatyousendsucceededor

failed.Thesecodesarenumerous,andeachisusedforaspecificpurpose,soyoucanfind

tutorialsabouttheseonline,andusetherightone.Wewillusethecode200whichtellsus

thatourconnectionsucceeded,andthenwewillbeabletosucceed.

SetupanewSwiftprojectonXcode6.OntotheMain.storyboard,dragabutton.Linkitas

anIBActiontotheviewController,andgiveitanameofyourchoice.Thenextthingisto

addfunctionalitytothisbutton.Thiscanbeachievedbyuseofafunction.Iwillcallmy

functionsendFunction.TheviewController.Swiftshouldbeasfollows:

importUIKit

classViewController:UIViewController{

funcsendFunction(){

println(ButtonPressed)

}

@IBActionfuncsendButton(sender:AnyObject){

sendFunction()

}


super.viewDidLoad()

//addanyadditionsetupaftertheviewisloaded.

}

overridefuncreceivedMemWarning(){

super.receivedMemWarning()

//anyresourceswiththeabilitytobecreatedshouldbedisposed.

}

}

TheButtonPressedmessagewillbedisplayedontheconsolelinearea.Incaseyouneed

tobeemailedwhenthereisapostrequest,youcanusethePHPcodebelow:

$reqVar=$_POST[data];

if(!empty($reqVar)){

mail([email protected],emailsubject,PostsetandButtonpressed);

}

Ifyouwanttoallowsomeonetoaccessyourserver,orifyouareconnectingtoadatabase,

makesurethatyouarecarefulsoastoavoidmaliciousattacks.

PostingfromSwifttoPHP

Declarethefollowingtwovariablesinyourfunction:

varu:NSURL=NSURL(string:http://url.com/path/to/file.php)!

varrqst:NSMutableURLRequest=NSMutableURLRequest(URL:url)

Belowtheabovelinesofcode,addthefollowing:

varbData=data=something

Foryoutospecifythemethodthatwearesendingin,addthefollowingcode:

rqst.HTTPMethod=POST

Wethenneedtoputtogetheralltheabove,andsendtotheserverasone.Thiscanbedone

asfollows:

rqst.HTTPBody=bodyData.dataUsingEncoding(NSUTF8StringEncoding);

NSURLConnection.sendAsynchronousRequest(rqst,queue:

NSOperationQueue.mainQueue())

{

(response,data,error)in

println(response)

}

Afterrunningtheappatthistime,aresponsewillbeseenintheconsolelog.Itwillhave

theentireresponse.

HowtoGettheStatusoftheHTTPCode

Intheabovecase,regardlessofwhetherthescriptssucceedsorfails,theuserwillbe

directedtotheViewController.WewanttodirecttheusertoanewViewControllerifthe

connectionexistsandthescriptrunscorrectly.Anifstatementistherightchoicehere,and

weshouldcombineitwiththecode200.Thiscanbedoneasfollows:

ifletHTTPResponse=responseas?NSHTTPURLResponse{

letsCode=HTTPResponse.statusCode

ifsCode==200{

//Thendosomething.

}

}

Youcannowrunyourapp.YounowknowhowtoposttoaPHPscriptfromSwift.We

havealsousedastatuscodetocheckwhetherthiswentoncorrectly.

Chapter10:

ConnectingtoiTunesSearchAPI

Inthischapter,youwillknowhowtoconnecttotheiTunessearchAPIusingSwift,

downloadtheJSONresults,andparsethemtothedictionaries.Thisinformationwillthen

beusedtopopulatethetableviews.Aclickeventwillthenbeaddedtothetableviewfor

thesakeofuserinteraction.Onclickingthisitem,theiTunesstorewillbeopened.

HowtoConnecttheUserInterface

Weshouldbeginbygettingareferencetothetableview.IntheViewController.swiftjust

outsideotherfunctionsandafterclassdefinition,addthefollowingcode:

@IBOutletvarappTV:UITableView

ThevariableappTVwillmakeitpossibletoconnecttotheTableViewinthestoryboard.

Savethefileabove.

Openthestoryboard.DragfromtheTableViewtotheViewcontrollerobject.Thiswill

linktheseobjects.

HowtoMaketheAPIRequest

Sincewehaveconnectedtheuserinterface,wecanmaketheAPIcall.Createanew

function,andgiveitanameofchoice.IhavecalledmineiTunesSearch(searchterm:

String).Aftersearchingarbitraryterms,thiswillcausetherequesttohappen.Writethe

codebelow:

funciTunesSearch(term:String){

//replacespaceswith+symbol.

variTunesTerm=term.stringByReplacingOccurrencesOfString(,withString:+,

options:NSStringCompareOptions.CaseInsensitiveSearch,range:nil)

//anythingthatisURLfriendlyshouldbeescaped

varescapedTerm=

iTunesTerm.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding)

varpath=https://itunes.apple.com/search?term=\(escapedTerm)&media=software

varurl:NSURL=NSURL(string:path)

varrqst:NSURLRequest=NSURLRequest(URL:url)

varctn:NSURLConnection=NSURLConnection(rqst:rqst,delegate:self,

startImmediately:false)

println(URLforsearchingiTunesAPI\(url))

ctn.start()

}

Wehavestartedbyfixingthesearchtermthatwepassin.TheiTunessearchAPi

recommendsthattermsshouldbeoftheformfirst+second+third+words.This

contradictstheformfirst%20cecond%20.ThisiswhywehaveusedanNSStringmethod,

thatis,stringByReplacingOccurencesOfString.

Thesearchtermwillbemodifiedbyreplacingalltheavailablespaceswitha+symbol.

Youcanalsoseetheescape,whichwillmakeitpossibletoescapethesearchtermifa

symbolthatcannotfitintheURLisfound.WehavealsodefinedanNSURL,whichcan

beusediniOS8snetworkAPIasaRequestURL.Thelinesbelowasusedabovearevery

important:




ThefirstlinehasusedtheurlthatwecreatedasthetargetURLtocreatean

NSURLRequestobject.Thesecondlinehasdonethemainjobbycreatingaconnection

whichistobeusedforsendingtherequest.Thepurposeofsettingthedelegatetoselfisto

beabletolistentotheinformationthatwillcomefromtheconnectioninsidetheview

controllerclass.Tobegintherequest,wehaveusedctn.start().

HowtoPreparefortheResponse

NowthatwehavesenttheRequest,weneedtopreparefortheresponsethatwewillget.

AttheendofviewDidLoad,addthefollowingcode:

iTunesSearch(JPSoftware)

JPSoftwareisoursearchterm,sothefunctionwillsearchforanysoftwareintheiTunes

storewhichcontainsthatphrase.Youcanchangethesearchtermtowhatyouwanttolook

forfromtheiTunesstore.Adataobjecttocontaintheresultsisneededforustogetthe

results.LetuscreateaninstanceofNSMutableDataasaclassmember.Insidethecurly

braceandjustbelowtheclassdefinition,addthefollowinglineofcodetoachievethis:

vard:NSMutableData=NSMutableData()

vartData:NSArray=NSArray()

Nowwearepreparedtoreceivetheresponse.Itistimetoreceiveit.Addthefollowing

chunkofcode:

funcctn(receivedResponse:NSURLConnection!,receivedResponseresponse:

NSURLResponse!){

//clearoutthedataobjectifanewrequestwasreceived.

self.d=NSMutableData()

}

funcctn(ctn:NSURLConnection!,receivedDatad:NSData!){

//addthereceiveddatatothedataobject

self.d.appendData(d)

}

funcctnFinishedLoading(ctn:NSURLConnection!){

//self.dshouldholdtheresultinginfo,requestiscomplete

//receiveddataisconvertedintoanobjectthroughJSONdeserialization

varerr:NSError

varjResult:NSDictionary=NSJSONSerialization.JSONObjectWithData(d,options:

NSJSONReadingOptions.MutableContainers,error:nil)asNSDictionary

ifjResult.count>0&&jResult[results].count>0{

varresults:NSArray=jResult[results]asNSArray

self.tData=results

self.appsTableView.reloadData()

}

}

TheNSURLconnectionreceivestheresponse,andthenitwillcalltherecivedResponse

method.Anewandemptyobjectwillbeinthelineself.d=NSMutableData().Oncethe

connectionisestablished,datawillbereceivedthroughthemethodreceivedData().The

importantinformationhereistheargumentpassedinthemethod.Everychunkofdatais

important,andthatiswhywehaveusedself.dtoappendit.

NotethatwehaveusedthectnFinishedLoading()methodinthefinalstep.Thisisafterthe

connectionhasbeenestablishedandallthedatahasbeenreceived.Wecanthenusethe

receiveddatainourapp.TheNSJSONSerializationconvertsthereceiveddataintodata

dictionaryobjectswhichareuseful.Thisisachievedbydeserializationoftheresultsfrom

iTunes.

Thefinalprocessinvolvesvalidatingtheresultssoastocheckonwhethertheyarewhat

weexpected.Theresultingdatacanthenbesettothetabledatabyself.tDataobject.The

appsTableViewreloadsitscontent.

HowtoUpdatetheTableViewUI

Rememberthatthetableviewhastwofunctions,acellfunctionforcreationand

modificationofcellsforeachrowandacountfunctionwhosepurposeistocountthe

numberofrows.Weneedtoputthedataweobtainedfromthewebintothetable.

Considerthecodebelow:

functView(tableView:UITableView!,numberOfRowsInSectionsection:Int)->Int{

returntData.count

}

functView(tView:UITableView!,cellForRowAtIndexPathindexPath:NSIndexPath!)->

UITableViewCell!{

letcell:UITableViewCell=UITableViewCell(style:UITableViewCellStyle.Subtitle,

reuseIdentifier:CellforTesting)

varrData:NSDictionary=self.tData[indexPath.row]asNSDictionary

cell.text=rData[trackName]asString

//GrabbingtheartworkUrl60keyforgettingimageURLforthethumbnailoftheapp

varuString:NSString=rData[artworkUrl60]asNSString

variURL:NSURL=NSURL(string:uString)

//DownloadrepresentationoftheimageasNSDataattheURL

variData:NSData=NSData(contentsOfURL:iURL)

cell.image=UIImage(data:iData)

//obtaintheformattedpricestringtobedisplayedonthesubtitle

varfPrice:NSString=rData[fPrice]asNSString

cell.detailTextLabel.text=fPrice

returncell

}

numberOfRowsInSectionwillreturnthenumberofresultingobjectsfromthetableData

member.ThisissettothectnFinishedLoadingmethod.Therownumberhasbeentograb

threevalues,sowedontreturntherownumberbutthethreevalues.Thesethreekeysare

thenusedtoconstructthetitle,thesubtitle,andtheimagethatwillbeputalongthecell.

TheViewController.swiftshouldlookasfollows:

importUIKit

classViewController:UIViewController,UITableViewDataSource,

UITableViewDelegate,NSURLConnectionDelegate,NSURLConnectionDataDelegate{

@IBOutletvarappsTableView:UITableView

vardata:NSMutableData=NSMutableData()

vartData:NSArray=NSArray()


super.viewDidLoad()

iTunesSearch(AngryBirds);

}

funciTunesSearch(term:String){

//replacespaceswith+symbol.

variTunesTerm=term.stringByReplacingOccurrencesOfString(,withString:+,

options:NSStringCompareOptions.CaseInsensitiveSearch,range:nil)

//AnythingwhichisnotURL-friendlyisescaped

varescapedTerm=

iTunesTerm.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding)

varuPath=https://itunes.apple.com/search?term=\

(escapedTerm)&media=software

varurl:NSURL=NSURL(string:uPath)




println(URLforsearchingiTunesAPI\(url))

ctn.start()

}

functView(tView:UITableView!,numberOfRowsInSectionsection:Int)->Int{

returntData.count

}

functView(tView:UITableView!,cellForRowAtIndexPathindexPath:NSIndexPath!)

->UITableViewCell!{

letcell:UITableViewCell=UITableViewCell(style:UITableViewCellStyle.Subtitle,

reuseIdentifier:CellforTesting)


cell.text=rData[trackName]asString

//GrabbingtheartworkUrl60keyforgettingimageURLforthethumbnailoftheapp

varuString:NSString=rData[artworkUrl60]asNSString

variURL:NSURL=NSURL(string:uString)

//DownloadrepresentationoftheimageasNSDataattheURL

variData:NSData=NSData(contentsOfURL:iURL)

cell.image=UIImage(data:iData)

//obtaintheformattedpricestringtobedisplayedonthesubtitle

varfPrice:NSString=rData[fPrice]asNSString

cell.detailTextLabel.text=fPrice

returncell

}

}

funcctn(receivedResponse:NSURLConnection!,receivedResponseresponse:

NSURLResponse!){

//clearoutthedataobjectifanewrequestwasreceived.

self.d=NSMutableData()

}

funcctn(ctn:NSURLConnection!,receivedDatad:NSData!){

//addthereceiveddatatothedataobject

self.d.appendData(d)

}

funcctnFinishedLoading(ctn:NSURLConnection!){

//self.dshouldholdtheresultinginfo,requestiscomplete

//receiveddataisconvertedintoanobjectthroughJSONdeserialization

varerr:NSError

varjResult:NSDictionary=NSJSONSerialization.JSONObjectWithData(d,options:

NSJSONReadingOptions.MutableContainers,error:nil)asNSDictionary

ifjResult.count>0&&jResult[results].count>0{

varresults:NSArray=jResult[results]asNSArray

self.tData=results

self.appsTableView.reloadData()

}

}

}

}

}

Nowtheappisreadyforrunning,sodoso.OursearchtermwasAngryBirds,sothe

followingwillbeobtainedastheresult:

Chapter11:

ImageLoadingandCachingAsynchronously

Ouraimistoaccessimagesstoredinthecache.Iftheydontexistinthecache,weshould

downloadthemwhileonabackgroundthread.Ifanimagehasbeendownloaded,we

shouldnotdownloaditagain,sinceitwillbestoredinthecacheandhencebeaccessible

fromthere.Considerthecodebelow:

functView(tView:UITableView,cellForRowAtIndexPathindexPath:NSIndexPath)->

UITableViewCell{

letcell:UITableViewCell=tView.dequeueReusableCellWithIdentifier(kCellIdentifier)

asUITableViewCell


//makingsurethatitexists

letcellText:String?=rData[trackName]as?String

cell.textLabel?.text=cellText

cell.imageView?.image=UIImage(named:B52)

//obtaintheformattedpricestringforthesubtitlebeingdisplayed.

letfPrice:NSString=rData[fPrice]asNSString

letuString=rData[artworkUrl60]asString

//Checkthecacheforexistingkey.

letuString=rData[artworkUrl60]asString

//checkingtheimagecacheforakey

varimg=self.imageCache[uString]

if(img==nil){

//downloadtheimageifitisnotexisting

varimgURL:NSURL=NSURL(string:uString)

//DownloadingNSDatarepresentationoftheimage

letrqst:NSURLRequest=NSURLRequest(URL:imgURL)

NSURLConnection.sendAsynchronousRequest(rqst,queue:

NSOperationQueue.mainQueue(),completionHandler:{(response:NSURLResponse!,d:

NSData!,error:NSError!)->Voidin

iferror==nil{

img=UIImage(data:d)

//Storingtheimageinthecache

self.imageCache[uString]=img

dispatch_async(dispatch_get_main_queue(),{

ifletcToUpdate=tableView.cellForRowAtIndexPath(indexPath){

cToUpdate.imageView?.image=img

}

})

}

else{

println(Error:\(error.localizedDescription))

}

})

}

else{

dispatch_async(dispatch_get_main_queue(),{

ifletcToUpdate=tView.cellForRowAtIndexPath(indexPath){

cToUpdate.imageView?.image=img

}

})

}

cell.detailTextLabel?.text=fPrice

returncell

}

Wehavefirstsetthecellsplaceholderimagebeforedownloadingtheimage.Createan

image,andimportittoyourprojectjustbyCtrl+drag.NameitB52.Setthecellstouse

thisimage.Wealsocheckedtheimagecacheforthepresenceoftheimage.

ThemethodsendAsynchronousRequestwilltakeaclosure/functionasaparameter.We

havecheckedforthepresenceofanerror,andifitdoesntexist,wewillcreateanimage

fromthedatad.Thelineself.imageCache[uString]=imghasthepurposeofsavingthe

imageintheimagecache,anditwillusetheimageURLasthekey.OntheUIthread,we

havesetthecellimage.

Youcannowruntheapp,andobservetheoutput.Thetableviewwillbeverysmooth.

Chapter12:

UsingObjective-CclassesinSwift

Youmightneedtouseoftheobjective-CclassesinSwift.Thisispossible.Justdothe

following:

1. Add.m(Objective-Cimplementation)

Thisfile,thatis,a.mone,shouldbeaddedtotheclassandnamedCustomObject.m

2. AddtheBridgingHeader

Duringtheadditionofthe.mfile,adialogwillappearwhichlooksasfollows:

JustclickonYes.

3. Add.h,theObjective-CHeader

Addanother.h.GiveitthenameCustomObject.h

4. BuildtheObjective-Cclass

InCustomObject.h,thisshouldbeasfollows:

#import

@interfaceCustomObject:NSObject

@property(strong,nonatomic)idaProperty;

-(void)aMethod;

@end

InCustomObject.m,tshouldbeasfollows:

#importCustomObject.h

@implementationCustomObject:NSObject

-(void)aMethod{

NSLog(@aMethodRan);

}

@end

5.AddaclasstotheBridging-Header

Thisshouldbe:

#importCustomObject.h

6.UseyourObject

variOfObject:CustomObject=CustomObject()

iOfObject.aProperty=HelloWorld

println(iOfObject.aProperty)

iOfObject.aMethod()

Thebridgingheaderissousefulsincewithit,thereisnoneedtoimportexplicitly.Youare

done,soyoucansafelyusetheclasses.

Chapter13:

AnimationsinSwift

WithSwift,onecancreateanappwithanimations.Thiscanbeachievedasfollows:

ContainerViewTransitions

Ifyouwanttoperformananimatedtransitionbetweenviews,performthistransitionina

parentcontainer.Intheexamplebelow,wearegoingtoperformananimatedtransition

betweentwoUIViewswhicharecolored.Thecontaineroftheanimationwillbethethird

UIView.LetusstartbysettingupthreeviewsintheviewDidLoad()function:

letcner=UIView()

letrSquare=UIView()//red

letbSquare=UIView()//blue


super.viewDidLoad()

//settingthecontainerframeandaddingittothescreen

self.cner.frame=CGRect(x:60,y:60,width:200,height:200)

self.view.addSubview(cner)

//settinguptheredframe

//boththeredandbluesquareframesshouldbelocatedatthesameposition

//wethenjustreuserSquare.frame

self.rSquare.frame=CGRect(x:0,y:0,width:200,height:200)

self.bSquare.frame=rSquare.frame

//setbackgroundcolors

self.rSquare.backgroundColor=UIColor.redColor()

self.bSquare.backgroundColor=UIColor.blueColor()

//letusjustaddtheredsquareforthistime.Thebluesquarewillbeaddedlaterin//the

animation.

self.container.addSubview(self.rSquare)

}

Justruntheapp.Aredsquarewillbetheoutput.

Nowtoachievetheanimationbetweenthetwosquares, letscreateadda@IBActionto

thebuttoninthestoryboard:

@IBActionfuncaButtonTapped(sender:AnyObject){

//createapairofmoreobjectsandassignthemtoasinglevariable(tuple)

letvws=(frontView:self.rSquare,backView:self.bSquare)

//setthestyleofthetransition

lettOptions=UIViewAnimationOptions.TransitionCurlUp

UIView.transitionWithView(self.cner,duration:1.0,options:tOptions,animations:{

//removingthefrontobject

vws.frontView.removeFromSuperview()

//addingtheotherobject

self.cner.addSubview(vws.backView)

},completion:{finishedin

//oncetheanimationhascompleted,anycodeaddedherewillbeapplied

})

}

After running theapp,youwillnotice thatwewillgetstuckwith thebluesquare.Lets

solvethisbyaddingsomelogiccodewhichwillcheckthevisiblesquare:

//createapairofmoreobjectsandassignthemtoasinglevariable(tuple)

varvws:(frontView:UIView,backView:UIView)

//ifrSquarehasasuperView,example,itisinthecontainer,

//setitasfront,andbSquareasback

//otherwise,dofliptheorder

if(self.rSquare.superview){

vws=(frontView:self.rSquare,backView:self.bSquare)

}

else{

vws=(frontView:self.bSquare,backView:self.rSquare)

}

Thetransitionwillthenbeaddedasfollows:

@IBActionfuncaButtonTapped(sender:AnyObject){

varvws:(frontView:UIView,backView:UIView)

if(self.rSquare.superview){

vws=(frontView:self.rSquare,backView:self.bSquare)

}

else{

vws=(frontView:self.bSquare,backView:self.rSquare)

}

//settingupthetransitionstyle

lettOptions=UIViewAnimationOptions.TransitionCurlUp

UIView.transitionFromView(vws.frontView,toView:vws.backView,duration:1.0,

options:tOptions,completion:nil)

}

Theabovewilloutputauniquetransition:

Theredviewwillbechangedtoblue.Youcanalsochoosetosetthetransitiontoanystyle

ofchoicesuchas:

lettOptions=UIViewAnimationOptions.TransitionFlipFromLeft

Chapter14:

CreatinganAudioPlayerwithSwift

Inthischapter,youwilllearnhowtocreateanaudioplayerwithSwift,comprisingofa

playbutton,stopbutton,andasliderforvolumeadjustment.Wewillbeginbyaddingan

audiofiletotheresourcesoftheproject.Ifyoudothis,anyaudioformatwillbe

supported.

Identifyanaudiofile,anddraganddropitintheSupportingfilesfolderofyourproject.I

haveputanmp3audiocalledtest.mp3andIhaveputitintheaudiofilesfolderofmy

project,sodothesame.

CreatingtheUserInterface

Wewanttoaddthetwobuttonsandtheslider.JustselecttheMain.storyboardanddisplay

theObjectLibrarybyView->Utilities->ShowObjectLibrary.Addthecomponentson

theviewwindowbydraggingthemfromtheLibrary.Modifythemtolookasfollows:

Selectthesceneviewwiththestoryboardcanvas.Getthelistofmenuoptionsbyselecting

theAutoLayoutResolveAutoLayoutIssuesmenu.Selectreset.Fromtheviewcanvas,

selectslider.DragthesliderjustbelowtheclassdeclarationintheAssistantEditor.Create

anoutletconnectionandcallitvControlinthedialogthatwillappear.Dragtheplay

buttontobelowtheviewDidLoad().EstablishanactionmethodnamedpAudioonthe

TouchUpinside.

DothesameforthestopbuttonandcalltheactionsAudio.Dragthesliderobjecttothe

AssistantEditorpanelbeneaththecreatedactions.Fromthedialog,establishaconnection

methodcalledadVolume.

SelecttheViewController.swiftfileafterclosingtheAssistantEditorpanel,andaddthe

followingtoit:

importUIKit

importAVFoundation

classViewController:UIViewController,AVAudioPlayerDelegate{

@IBOutletweakvarvControl:UISlider!

varaudioPlayer:AVAudioPlayer?

ActionMethods

ImplementthefollowingmethodsintheViewController.swiftfile:

@IBActionfuncpAudio(sender:AnyObject){

ifletplyr=audioPlayer{

plyr.play()

}

}

@IBActionfuncsAudio(sender:AnyObject){

ifletplyr=audioPlayer{

plyr.stop()

}

}

@IBActionfuncadVolume(sender:AnyObject){

ifaudioPlayer!=nil{

audioPlayer?.volume=vControl.value

}

}

CreationandInitializationofAVAudioPlayerObject

AddthefollowingcodeintheviewDidLoad()methodoftheViewController.swiftfile:


super.viewDidLoad()

letu=NSURL.fileURLWithPath(

NSBundle.mainBundle().pathForResource(test,

ofType:mp3)!)

vare:NSError?

audioPlayer=AVAudioPlayer(contentsOfURL:u,e:&error)

ifleterror=e{

println(audioPlayererror\(error.localizedDescription))

}else{

audioPlayer?.delegate=self

audioPlayer?.prepareToPlay()

}

}

ImplementationoftheAVAudioPlayerDelegateProtocolMethods

Todothis,addthefollowingprotocolstotheViewController.swiftfile:

funcaudioPlayerDidFinishPlaying(plyr:AVAudioPlayer!,succeeded

flag:Bool){

}

funcaudioPlayerDecodeErrorDidOccur(plyr:AVAudioPlayer!,

error:NSError!){

}

funcaudioPlayerBeginInterruption(plyr:AVAudioPlayer!){

}

funcaudioPlayerEndInterruption(plyr:AVAudioPlayer!){

}

Youcannowrunyourappandplayaroundwiththetwobuttonsandtheslider.

Conclusion

It can be concluded that iOS 8 is used on Apple devices. Swift is the programming

language developed recently for the purpose of creating iOS 8 apps. iOS 8 is superior

comparedtothepreviousiOS7sinceitofferssomebetterfunctionalitiescomparedtothe

latter.ForonetoprograminSwift,Xcode6needstobesetupfirst,andthisisaneasy

task.

Whileprogramming inSwift,Objective-Cclasses canbe imported to theSwift project.

The vice versa is also true. This language has been used to create amazing apps for

devices running iOS8whicharenowavailable in the iTunes store.These apps include

coolfeaturessuchasplayingaudio,animations,andevenloadingimagesasynchronously.

Book DescriptionIntroductionChapter 1: DefinitionChapter 2: Getting Started with iOS 8 Swift ProgrammingChapter 3: Variables and Constants in SwiftChapter 4: Type AnnotationsChapter 5: Tuples in SwiftChapter 6: Enumerations in SwiftRaw Values

Chapter 7: UIAlertView in SwiftChapter 8: NSTimer in SwiftProject SetupCoding the TimerStopping the NSTimerClearing the NSTimer

Chapter 9: Swift and PHPPosting from Swift to PHPHow to Get the Status of the HTTP Code

Chapter 10: Connecting to iTunes Search APIHow to Connect the User InterfaceHow to Make the API RequestHow to Prepare for the ResponseHow to Update the Table View UI

Chapter 11: Image Loading and Caching AsynchronouslyChapter 12: Using Objective-C classes in SwiftChapter 13: Animations in SwiftContainer View Transitions

Chapter 14: Creating an Audio Player with SwiftCreating the User InterfaceAction MethodsCreation and Initialization of AVAudioPlayer ObjectImplementation of the AVAudioPlayerDelegate Protocol Methods

Conclusion

IOS 8 Programming - With Swift a Step by Step Guide Book for Beginners

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