android boot camp 2012 - slides

Marko Gargenta marakana.com

ANDROID OVERVIEW

About Marko Gargenta

Developer of Android Bootcamp for Marakana.

Instructor for 1,000s of developers on Android at Qualcomm, Cisco, Motorola, DoD and other great orgs.

Author of Learning Android published by O’Reilly.

Speaker at OSCON (3x), ACM, IEEE, SDC, AnDevCon.

Co-Founder of SFAndroid.org

Co-Chair of Android Open conference: AndroidOpen.com

Agenda

•  Android Then & Now •  Android versions •  The Stack •  Opera<ng System Features

•  Hello World!

•  Main Building Blocks •  Architec<ng an App •  Android UI •  Debugging & Logging •  Android Security •  Summary

ANDROID THEN & NOW

History and Possible Future

2005 Google buys Android, Inc. Work on Dalvik starts

2007 Open Handset Alliance announced Early SoOware Development Kit

2008-‐2010 Android becomes the dominant mobile plaTorm

2011 Games, Tablets, TVs

Future? Beyond phones

Vision for Android

Our goal is not just a single device. Our vision is a mobile platform that runs on many many different devices.

– Eric Schmidt

PlaTorm Versions Version API Level Nickname

Android 1.0 1 Android

Android 1.1 2 Android

Android 1.5 3 Cupcake

Android 1.6 4 Donut

Android 2.0 5 Éclair



Android 2.2 8 FroYo

Android 2.3 9 Gingerbread

Android 2.3.3 10 Gingerbread

Android 3.x 11, 12, 13 Honeycomb

Android 4.0 14 Ice Cream Sandwich

Version Distribu<on

Source: Android.com

Historical Distribu<on

Source: Android.com

Add-‐Ons

TouchWiz MotoBlur SenseUI

“With Google”

Devices that have “with Google” add-on feature a set of Google’s proprietary applications, such as Maps, Gmail, Gtalk, and many others.

OEMs and carriers typically enter into a licensing agreement with Google in order to distribute Google version of Android.

ANDROID STACK

The Stack

Linux Kernel

Libraries

Application Framework

Applications

Home Contacts Phone Browser Other

Activity Manager

Window Manager

ContentProviders

View System

PackageManager

TelephonyManager

Resource Manager

LocationManager

NotiicationManager

Surface Manager

OpenGL

SGL

Media Framework

FreeType

SSL

SQLite

WebKit

libc

Android Runtime

Core Libs

Dalvik VM

DisplayDriver

KeypadDriver

CameraDriver

WiFiDriver

FlashDriver

AudioDriver

BinderDriver

PowerMgmt

Linux Kernel Android runs on Linux.

Linux provides: Hardware abstraction layer Memory management Process management Networking

Users never see Linux sub system

The adb shell command opens Linux shell

Linux Kernel

Libraries


Applications


Activity Manager

Window Manager

ContentProviders

View System

PackageManager

TelephonyManager

Resource Manager

LocationManager

NotiicationManager

Surface Manager

OpenGL

SGL

Media Framework

FreeType

SSL

SQLite

WebKit

libc

Android Runtime

Core Libs

Dalvik VM

DisplayDriver

KeypadDriver

CameraDriver

WiFiDriver

FlashDriver

AudioDriver

BinderDriver

PowerMgmt

Android™ Stack

Na<ve Libraries Pieces borrowed from other open source projects:

Bionic, a super fast and small license-friendly libc library optimized for Android

WebKit library for fast HTML rendering

OpenGL for graphics

Media codecs offer support for major audio/video codecs

SQLite database

Much more…

Linux Kernel

Libraries


Applications


Activity Manager

Window Manager

ContentProviders

View System

PackageManager

TelephonyManager

Resource Manager

LocationManager

NotiicationManager

Surface Manager

OpenGL

SGL

Media Framework

FreeType

SSL

SQLite

WebKit

libc

Android Runtime

Core Libs

Dalvik VM

DisplayDriver

KeypadDriver

CameraDriver

WiFiDriver

FlashDriver

AudioDriver

BinderDriver

PowerMgmt

Dalvik Dalvik VM is Android implementation of Java VM

Dalvik is optimized for mobile devices: •  Battery consumption •  CPU capabilities

Key Dalvik differences: •  Register-based versus stack-based VM •  Dalvik runs .dex files •  More efficient and compact implementation •  Different set of Java libraries than JDK

Applica<on Framework The rich set of system services wrapped in an intuitive Java API.

This ecosystem that developers can easily tap into is what makes writing apps for Android easy.

Location, web, telephony, WiFi, Bluetooth, notifications, media, camera, just to name a few.

Linux Kernel

Libraries


Applications


Activity Manager

Window Manager

ContentProviders

View System

PackageManager

TelephonyManager

Resource Manager

LocationManager

NotiicationManager

Surface Manager

OpenGL

SGL

Media Framework

FreeType

SSL

SQLite

WebKit

libc

Android Runtime

Core Libs

Dalvik VM

DisplayDriver

KeypadDriver

CameraDriver

WiFiDriver

FlashDriver

AudioDriver

BinderDriver

PowerMgmt

Applica<ons

Dalvik Executable + Resources = APK Must be signed (but debug key is okay for development) Many markets with different policies

App Distribu<on

•  One of the markets •  Side loading •  Internal app directory

Markets

•  Google Android Market •  Amazon Android Market

•  Other emerging markets

Side Loading

Internal App Directory

OPERATING SYSTEM FEATURES

Mul<media AudioPlayer lets you simply specify the audio resource and play it.

VideoView is a View that you can drop anywhere in your activity, point to a video file and play it.

XML: <VideoView android:id="@+id/video" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_gravity="center” />

Java: player = (VideoView) findViewById(R.id.video); player.setVideoPath("/sdcard/samplevideo.3gp"); player.start();

Supported Media Formats Audio AAC LC/LTP, HE-‐AACv1 (AAC+), HE-‐

AACv2, AMR-‐NB, AMR-‐WB, MP3, MIDI, RTTTL/RTX, Ogg, PCM/WAVE

Video H.263, H.264, MPEG-‐4, VP8

Image JPEG, GIF, PNG, BMP

RTSP and HTTP progressive streaming. HTTP live streaming coming soon. More native support in the works.

Native support available via Khronos OpenMax IL

Cloud to Device Push

Big deal for many pull-based apps. Will make devices use less battery.

C2DM – The Big Picture

Device Administra<on

New in FroYo: Android Device Admin API.

Administrator can set: Enable passwords Set password quality Max failed logins Prompt for new password Remotely wipe device data Lock the device

App requests Device Admin permissions. If granted, admin policies apply. If not, app doesn’t work.

Policies could be hard-coded or dynamic.

Third-party enterprise solutions use this framework to build DM policies.

File System The file system has three main mount points. One for system, one for the apps, and one for whatever.

Each app has its own sandbox easily accessible to it. No one else can access its data. The sandbox is in /data/data/com.marakana.yamba/

SDCard is expected to always be there. It’s a good place for large files, such as movies and music. Everyone can access it.

System partition is where the entire Android operating system is, customized by OEM or not.

HELLO WORLD!

Android SDK -‐ What’s In The Box

SDK

Tools Docs Platforms

Data Skins Images Samples

Add-ons Google

Create New Project Use the Eclipse tool to create a new Android project.

Here are some key constructs:

Project Eclipse construct

Target minimum to run

App name whatever

Package Java package

Ac<vity Java class

Anatomy of An App

Java Code +

XML and Other Resources

+ Manifest File

= Android App

Running on Emulator

Emulator, not a simulator

MAIN BUILDING BLOCKS

Yamba Demo

Let’s see a real-world medium complexity Android app in action:

Yamba: Yet Another Micro Blogging App

Ac<vi<es

Android Application

Main Activity AnotherActivity

AnotherActivity

An Activity represents a screen or a window. Sort of.

Ac<vity Lifecycle Activities have a well-defined lifecycle. The Android OS manages your activity by changing its state. You fill in the blanks.

Intents

Intents represent events or actions.

They are to Android apps what hyperlinks are to websites. Sort of.

Intents can be implicit or explicit.

Services

Services are code that runs in the background. They can be started and stopped. Services doesn’t have UI.

Service Lifecycle

Service also has a lifecycle, but it’s much simpler than activity’s.

An activity typically starts and stops a service to do some work for it in the background, such as play music, check for new tweets, etc.

Services can be bound or unbound.

Remote Services

Content Providers

Content Providers share content with applications across application boundaries. Examples of built-in Content Providers are: Contacts, MediaStore, Settings and more.

Content Provider Example

Broadcast Receivers

An Intent-based publish-subscribe mechanism. Great for listening system events such as SMS messages.

Architecture of An App

An Android application is a collection of many different building blocks. They are loosely coupled and can be reconfigured by the developer easily, or at least that’s the intention.

Let’s look at 7 stages of Yamba next.

Yamba Part 1

Yamba Part 2

Yamba Part 3

Yamba Part 4

Yamba Part 5

Yamba Part 6

Yamba Part 7

ANDROID USER INTERFACE

Two UI Approaches

Procedural DeclaraKve

You write Java code Similar to Swing or AWT

You write XML code Similar to HTML of a web page

You can mix and match both styles. Best practice:

•  Start with XML and declare most of UI •  Switch to Java and implement the UI logic

XML-‐Based User Interface

Use WYSIWYG tools to build powerful XML-based UI. Easily customize it from Java. Separate concerns.

Views and Layouts

Layouts contain widgets and other layouts forming a “composite” pattern.

Linear Layout

One of the most commonly used layouts. It lays its children next to each other, either horizontally or vertically.

Rela<ve Layout

Children of relative layout are placed in relationship to each other. This layout is efficient.

Table Layout

Table layout puts its children into table rows and columns. It is similar to an HTML table.

Frame Layout

Frame layout places its children on top of each other, like a deck of cards. It is useful for widgets such as tabs or as a placeholder for views added programmatically.

Common UI Components

Android UI includes many common modern UI widgets, such as Buttons, Tabs, Progress Bars, Date and Time Pickers, etc.

Selec<on Components

Some UI widgets may be linked to zillion pieces of data. Examples are ListView and Spinners (pull-downs).

Adapters

To make sure they run smoothly, Android uses Adapters to connect them to their data sources. A typical data source is an Array or a Database.

Data Source

Adapter

Complex Components

Certain high-level components are simply available just like Views. Adding a Map or a Video to your application is almost like adding a Button or a piece of text.

Menus and Dialogs

Graphics & Anima<on

Android has rich support for 2D graphics. You can draw & animate from XML. You can use OpenGL for 3D graphics.

Mul<media AudioPlayer lets you simply specify the audio resource and play it.

VideoView is a View that you can drop anywhere in your activity, point to a video file and play it.

XML: <VideoView android:id="@+id/video" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_gravity="center” />

Java: player = (VideoView) findViewById(R.id.video); player.setVideoPath("/sdcard/samplevideo.3gp"); player.start();

DEBUGGING ANDROID APPS

LogCat

The universal, most versatile way to track what is going on in your app.

Can be viewed via command line or Eclipse.

Logs can be generated both from SDK Java code, or low-level C code via Bionic libc extension.

Debugger

Your standard debugger is included in SDK, with all the usual bells & whistles.

TraceView

TraceView helps you profile you application and find bottlenecks. It shows execution of various calls through the entire stack. You can zoom into specific calls.

Hierarchy Viewer

Hierarchy Viewer helps you analyze your User Interface.

Base UI tends to be the most “expensive” part of your application, this tool is very useful.

ANDROID SECURITY

Security Overview No app can adversely impact other apps, user, or OS

Cannot read/write user’s private data Cannot read other app’s data Cannot perform network access Cannot keep device awake, and so on

Each application is its own sandbox To share resources, apps need to request permissions User must grant permissions at install time

Linux manages security Not up to Dalvik (Java) but outsourced to Linux Native code (NDK) also adheres to sandboxing

Applica<on Sandboxing An application is an island on its own.

It contains any number of Activities, Services, Receivers and Providers.

It has its own file system, database, place to store native libraries.

No other app can access any of its data without prior permission.

Permissions

A component that does something potentially dangerous can require callers to have permission to access it.

App that wants to use it must have user grant it permission.

Permissions are granted at install time. All or nothing. Forever.

Some System Permissions ACCESS_COARSE_LOCATION ACCESS_FINE_LOCATION

ACCESS_NETWORK_STATE ACCESS_WIFI_STATE

BATTERY_STATS BLUETOOTH

CALL_PHONE CALL_PRIVILEGED

CAMERA DEVICE_POWER

GET_ACCOUNTS GET_TASKS

INSTALL_PACKAGES INTERNET

KILL_BACKGROUND_PROCESSES NFC

READ_CALENDAR READ_CONTACTS

RECEIVE_SMS RECORD_AUDIO

WRITE_EXTERNAL_STORAGE WRITE_SETTINGS

Summary

Android is open and complete system for mobile development. It is based on Java and augmented with XML.

It takes about 3-5 days of intensive training to learn Android application development for someone who has basic Java (or similar) experience.

Marko Gargenta, Marakana.com [email protected] +1-415-647-7000

android boot camp 2012 - slides

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