Getting started with Android and App Engine

Transcription

1 Getting started with Android and App Engine

2 About us Tim Roes Software Developer (Mobile/Web Solutions) at inovex GmbH

3 About us Daniel Bälz Student/Android Developer at inovex GmbH plus.dbaelz.de

4 About you

5 Agenda Introduction to Android Android Basics Managing Layouts and Resources Lists and Adapters Navigation between Components App Engine Basics Multithreading

6 Disclaimer All pictures annotated with are taken from the official documentation at

7 Introduction to Android or inside a droid

8 The Android Platform Apps (Java) Native Code (C/C++) Dalvik VM Android Platform Linux Kernel

9 APK application.apk classes.dex resources AndroidManifest.xml Signatures

10 API Level Level Android Version Version Name x x x x x x Froyo Gingerbread Gingerbread MR1 Honeycomb Ice Cream Sandwich Ice Cream Sandwich MR1 Jelly Bean Jelly Bean MR1 Jelly Bean MR2 KitKat

11 API Level distribution Source:

12 Tooling Old System: New System:* Eclipse IDE ADT Ant Android Studio Gradle * Beta

13 Android SDK Manager

14 Android AVD Manager

15 Android Debug Bridge ADB

16 Demo Project Share links with other people Links will be stored on App Engine Results may vary

17 Get ready or rollin' the droid

18 Android Basics

19 Activity A "window" in an application

20 Activity An application contains multiple activities Only one activity displayed at a time Contains the UI elements, menus, etc. Contains code to glue the logic and UI together Defined in AndroidManifest.xml

21 Lifecycle

22 Shutdown Phase Activity

23 Startup Phase Activity

24 Managing Layouts and Resources or create your UI and it

25 Resources Resource types: Strings Drawable Layouts Styles (of elements) Menus Colors and more...

26 Resource Qualifier Possible qualifiers: language/region (e.g. en-rus, de) screen sizes (e.g. small, normal, large) screen orientation (e.g. port, land) screen pixel density (e.g. mdpi, hdpi, xhdpi) platform version level (e.g. v8, v14, v15) and more...

27 Strings in res/values/strings.xml <?xml version="1.0" encoding="utf-8"?> <resources> <string name="app_name">mycloudapplication</string> <string name="hello_world">hello world!</string> <string name="settings">settings</string> </resources>

28 Strings in res/values-de/strings.xml <?xml version="1.0" encoding="utf-8"?> <resources> <string name="app_name">meinewolkenanwendung</string> <string name="hello_world">hallo Welt!</string> <string name="settings">einstellungen</string> </resources>

29 Screen densities 1280x720 ca. 300 dpi 1920x1080 ca. 450 dpi

30 Drawables

31 Layouts Describes the elements (views) on the screen Basically two different types: View ViewGroup

32 Views One element on the screen, e.g. TextView Button Switches EditText and more...

33 ViewGroups Arrange views on the screen in a specific manner LinearLayout (horizontal/vertical) RelativeLayout and more...

34 Lists and Adapters

35 Lists ListView GridView

36 Adapters ListView/GridView Adapter Data Item Views

37 Navigation between Components

38 Intents Used for all communication between components: Activities, Services, BroadcastReceivers

39 Explicit vs. Implicit Intents Implicit (what): Explicit (who): View an image Open a link Send/Edit a file Call a specific component What to do (action) Which data (data) Target component Extra data (bundle)

40 Intent Example Implicit Intent intent = new Intent(Intent.ACTION_VIEW); intent.setdata(uri.parse(" startactivity(intent); Explicit Intent ex = new Intent(this, Activity2.class); ex.putextra("id", 42); startactivity(ex);

41 App Engine Basics

42 App Engine Platform as a Service for developing and hosting web applications Datastore for persistence Supports Python, Java, PHP and Go Most parts free for use

43 Structure Source:

44 Using App Engine Gradle Plugin Android Studio integration Supports local development Developer Console* for new projects Helpful tool APIs Explorer *

45 Persistence Schemaless NoSQL datastore Access via JDO, JPA and a low level Datastore API Third party frameworks Objectify Slim3

46 Objectify Java data access API for App Engine datastore Simple and fast method for persistence Good documentation

47 Multithreading

48 The problem Click Click Click Click Swipe Swipe Click Click OK Bad

49 ANR After 5 seconds Android will "solve" that problem for you

50 Solution Click Click Swipe Click UI-Thread Other Threads

51 AsyncTask class DownloadFileTask extends AsyncTask<URL, Void, File> { } File doinbackground(url... url) { // Background thread, do download here and // return the downloaded File } void onpostexecute(file result) { // Called on UI-Thread. Change UI in whatever // way with downloaded File }

52 Sample Project

53 Publish Apps

54 Publish your APK Sign APK with a release key Distribute it: Google Play ($25 one time fee / account) Other App Stores (Amazon, AndroidPIT,...) Direct distribution (distribute APK) Don't lose release key

55 Outlook or what you can do tomorrow

56 Documentation Trainings API Guides Reference

57 Saving Data (SQLite, SharedPreferences, File System) Design (Themes & Styles) Media Handling (Camera, Audio In/Output, Videos) Graphics Pipeline (Open GL ES, Renderscript, Animations, Canvas) Network (Backup, SyncAdapters,...) Accessibility Notifications Optimization (Performance, Traffic, Battery) More Components (Service, Broadcast Receiver) Automated Testing Responsive Design (Fragments) Connectivity (Bluetooth, WiFi, NFC) Permissions Locations (GPS, Coarse Locations, Fuse)

58 Support Library Support Library for backward support of newer APIs to older platforms: Notifications Fragments Several newer Views ActionBar Printing support and more...

59 View Libraries Sources:

60 Utilization Libraries View injection Easy image loading/caching Dependency injection Message bus and more...

61 Other Google Services Google Play Services Google Play Game Services and more...

62 Questions? or better run to catch the bus ;-) In case of further questions:

63 OPTIONAL CONTENT

64 Menus

65 Menus in Android

66 SharedPreferences

67 Fragments

68 Fragments Parts of an activity

69 Fragments - why?

70 Fragment Lifecycle

71 Fragment Lifecycle onattach(activity) - Fragment got bound to a specific activity oncreate() - Fragment is created (same like Activity) oncreateview(..) - Method that must load the UI and return it onstart()/onresume()/onpause()/onstop() - Same as on activity