Android Programming Cookbook

151 Pages·2016·8.22 MB·English

by  Chryssa Aliferi

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Android Programming Cookbook
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Contents
1 AndroidTutorialForBeginners 1
1.1 WhatisAndroid? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 InstallingAndroidStudio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.3 AndroidversionsandAndroidSDKManager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.4 Supportingdifferentscreensizes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.5 AndroidProjectStructure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.6 Create"HelloAndroidWorld"application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.6.1 CreateaNewAndroidStudioProject . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.6.2 CreatethesourcecodeofasimpleFirstAndroidApplicationActivity . . . . . . . . . . . . . . . . . . . . 13
1.6.3 Createthelayoutoftheproject . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.6.4 AndroidManifest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.6.5 EdittheFirstAndroidApplicationdimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
1.6.6 EdittheFirstAndroidApplicationstrings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
1.6.7 Addthedrawableforeveryscreendensity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
1.6.8 Build,compileandrun . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
1.7 DownloadtheAndroidStudioProject . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
1.8 Howtocontinue? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2 AndroidProjectmigrationfromEclipsetoAndroidStudio 19
2.1 WhytouseAndroidStudiooverEclipseADT? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.2 AndroidStudionewprojectstructure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.3 Gradleandbuild.gradle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.4 SimpleEclipseADTprojectmigrationtoAndroidStudio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.5 Javacodeandresourcesmigration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2.6 AndroidManifest.xmlandbuild.gradlefile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.7 DownloadtheAndroidStudioProject . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
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3 AndroidGoogleMapsv2Tutorial 33
3.1 CreateaGoogleMapsAPIkey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
3.2 CreateaNewAndroidApplicationProject . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3.3 ImportingGooglePlayServicesinyourproject . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
3.4 CreatethelayoutofthemainGoogleMapsv2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
3.5 CreatethesourcecodeofthemainAndroidGoogleMapsActivity . . . . . . . . . . . . . . . . . . . . . . . . . . 52
3.6 CreatingthesourcecodeofthehelperclassCustomMarker.java . . . . . . . . . . . . . . . . . . . . . . . . . . 58
3.7 CreatingthesourcecodeofthehelperclassLatLngInterpolator.java . . . . . . . . . . . . . . . . . . . . . . . . 59
3.8 CreatingthesourcecodeofthehelperclassMarkerAnimation.java . . . . . . . . . . . . . . . . . . . . . . . . . 61
3.9 ModifyingtheAndroidManifest.xml . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
3.10 Build,compileandrun . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
3.11 DownloadtheEclipseProject . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
4 AndroidStartServiceonBootExample 67
4.1 CreateaNewAndroidStudioProject. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
4.2 CreatethelayoutandthesourcecodeofasimpleAndroidStartServiceOnBootActivity . . . . . . . . . . . . . . 71
4.3 CreatingthesourcecodeoftheBroadcastReceiverOnBootCompleteService . . . . . . . . . . . . . . . . . . . . 72
4.4 CreatingthesourcecodeoftheAndroidServiceStartOnBootService . . . . . . . . . . . . . . . . . . . . . . . . 72
4.5 EditingtheAndroidManifestxml . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
4.6 Build,compileandrun . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
4.7 DownloadtheAndroidStudioProject . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
5 AndroidBluetoothConnectionExample 80
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
5.2 CreateaNewAndroidStudioProject. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
5.3 CreatethelayoutoftheBluetoothChat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
5.4 CreatethesourcecodeoftheBluetoothChat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
5.5 CreatethesourcecodeoftheBluetoothChatService . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
5.6 CreatethelayoutoftheDeviceListActivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
5.7 CreatethesourcecodeoftheDeviceListActivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
5.8 AndroidManifest.xml . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
5.9 build.gradle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
5.10 Build,compileandrun . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
5.11 DownloadtheAndroidStudioProject . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
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6 AndroidMultitouchExample 105
6.1 CreateaNewAndroidStudioProject. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
6.2 Createthelayoutoftheproject . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
6.3 CreatingthesourcecodeoftheTouchableFrameLayoutFrameLayout . . . . . . . . . . . . . . . . . . . . . . . 110
6.4 CreatingthesourcecodeofthemainAndroidMultitouchActivityActivity . . . . . . . . . . . . . . . . . . . . . 113
6.5 Createthestrings.xml . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
6.6 AndroidManifest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
6.7 build.gradle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
6.8 Build,compileandrun . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
6.9 DownloadtheAndroidStudioProject . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
7 AndroidStackViewExample 119
7.1 CreateaNewAndroidStudioProject. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
7.2 CreatethelayoutoftheAndroidStackViewActivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
7.3 CreatethelayoutoftheStackViewitems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
7.4 CreatethesourcecodeoftheStackItems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
7.5 CreatethesourcecodeoftheStackAdapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
7.6 CreatethesourcecodeoftheAndroidStackViewActivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
7.7 AndroidManifest.xml . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
7.8 build.gradle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
7.9 Build,compileandrun . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
7.10 DownloadtheAndroidStudioProject . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
8 AndroidViewPagerExample 130
8.1 CreateaNewAndroidStudioProject. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
8.2 CreatethelayoutofthemainAndroidViewPagerExample . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
8.3 CreatethesourcecodeofthemainAndroidViewPagerExampleActivity . . . . . . . . . . . . . . . . . . . . . . 135
8.4 CreatethelayoutofthemainFragmentViewPager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
8.5 CreatethesourcecodeofthemainFragmentViewPagersupport.v4.app.Fragment . . . . . . . . . . . . . . . . . 136
8.6 AndroidManifest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
8.7 Composingbuild.gradlefile. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
8.8 Build,compileandrun . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
8.9 DownloadtheAndroidStudioProject . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
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Copyright (c) Exelixis Media P.C., 2016
All rights reserved. Without limiting the rights under
copyright reserved above, no part of this publication
may be reproduced, stored or introduced into a retrieval system, or
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permission of the copyright owner.
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Preface
AndroidisamobileoperatingsystemdevelopedbyGoogle,basedontheLinuxkernelanddesignedprimarilyfortouchscreen
mobile devices such as smartphones and tablets. Android’s user interface is mainly based on direct manipulation, using touch
gesturesthatlooselycorrespondtoreal-worldactions,suchasswiping,tappingandpinching,tomanipulateon-screenobjects,
alongwithavirtualkeyboardfortextinput.
Inadditiontotouchscreendevices,GooglehasfurtherdevelopedAndroidTVfortelevisions,AndroidAutoforcars,andAndroid
Wearforwristwatches,eachwithaspecializeduserinterface. VariantsofAndroidarealsousedonnotebooks,gameconsoles,
digitalcameras,andotherelectronics.
Androidhasthelargestinstalledbaseofalloperatingsystemsofanykind. AndroidhasbeenthebestsellingOSontabletssince
2013,andonsmartphonesitisdominantbyanymetric. (Source: https://en.wikipedia.org/wiki/Android_(operating_system))
Inthisebook,weprovideacompilationofAndroidprogrammingexamplesthatwillhelpyoukick-startyourownwebprojects.
Wecoverawiderangeoftopics,fromServicesandViews,toGoogleMapsandBluetoothfunctionality.Withourstraightforward
tutorials,youwillbeabletogetyourownprojectsupandrunninginminimumtime.
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About the Author
ChryssaisaComputerSciencegraduatefromAthensUniversityofEconomicandBusiness. Duringherstudies,Chryssacarried
outagreatvarietyofprojectsrangingfromnetworkingtosoftwareengineering.
Sheisverykeenonfrontenddevelopmentespeciallyonmobiletechnologiesandwebapplications. Shehasworkedasajunior
SoftwareEngineerinthetelecommunicationsareaandcurrentlyworksasanAndroidDeveloper.
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Chapter 1
Android Tutorial For Beginners
There are lots of reasons why more and more people are interested in learing how to be able to develop Android applications.
Unarguably,Androidisthemostpopularmobileoperatingsystem,withalmost2billiondevicesactivatedanditoffersaunified
approachtoapplicationdevelopmentformobiledevices.
Thatmeans,thatdevelopersneedonlydevelopforAndroid,andtheirapplicationswillbeabletorunondifferentdevicespowered
byAndroid. ThisparticularassetgivesAndroidendlesspossibilites! Thismeansthatandapplicationthatisdesignedtoworkon
mobilephonedevicescanbealsotransferedtoAndroidpoweredTVsetsorAndroidCarsystems.
Thisiswhy,Androidisanexcitingspacetomakeappsthatcanhelpyouineveryaspectofyourlife,canhelpyoucommunicate,
organize,educate,entertainorjusttomakeyourlifeeasierineverydevicethattheymightrunon!
Inthisspecialexample,wearegoingtosetourAndroidDevelopmentStudioIDE,makeourveryfirstAndroidapplication
anddiscovertheAndroidDevelopmentworldintheeasiestpossibleway.
The mobile development world can be very fun, because the direct results we see when creating our own application, can be
highlymotivatingandrewarding.
1.1 What is Android?
Android is a mobile operating system currently developed by Google, based on the Linux kernel and designed primarily for
touchscreen mobile devices such as smartphones and tablets. And as we said before, Android offers a unified approach to
applicationdevelopmentformobiledevices.
Androidisanopen-sourceoperatingsystemnamedAndroid.Googlehasmadethecodeforallthelow-level"stuff"aswellasthe
neededmiddlewaretopoweranduseanelectronicdevice,andgaveAndroidfreelytoanyonewhowantstowritecodeandbuild
theoperatingsystemfromit. Thereisevenafullapplicationframeworkincluded,sothird-partyappscanbebuiltandinstalled,
thenmadeavailablefortheusertorunastheylike.
The"proper"nameforthisistheAndroidOpenSourceProject,andthisiswhatpeoplemeanwhentheysaythingslikeAndroid
isopenandfree. Android,inthisiteration,isfreeforanyonetouseastheylike.
1.2 Installing Android Studio
In order to write an Android application, we are going to need a development environment. Google has made a very useful
toolforallAndroidDevelopers, theAndroidStudio. AndroidStudioistheofficialIDEforAndroiddevelopment, andwitha
singledownloadincludeseverythingyouneedtobegindevelopingAndroidapps. Includedinthedownloadkit,aretheSoftware
DevelopmentKit(SDK),withalltheAndroidlibrarieswemayneed, andtheinfrastructuretodownloadthemanyAndroid
emulatorinstances,sothatwecaninitiallyrunourapplication,withoutneedingarealdevice.
So,wearegoingtodownloadandinstallAndroidStudio.
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First we have to have installed the Java Development Kit (JDK) from Oracle. If you do not, please you should download the
latestJDKfromtheOracle’sspecialsectionhere.
Figure1.1: AndroidStudioInstallation-step1