Android N 7.0DevFest 2016 event, Iqra University, KarachiPresenter: Imam Raza

Speaker.bio.toString()

Senior Software Architect @ Folio3

Specialities:

Enterprise Software Architecture,

Mobile Software Architecture

About this presentation

me.loveQuestion==true. Let's have interactive session

The content is designed on basis of industry experience.

Love to do hands-on coding session but this session is not hands-on. Why?

See in later slides

Switching the gear with interesting silicon valley facts.

Agenda

Android Marketing Statistics

Android N

Market Statistic shared in DevFest 2012

Today Market Statistic

9 in every 10 smartphones is Android

Switching the gear

A mandatory books for all silicon

valley graduates seeking jobs.

Android N

What’s new in Android N?

Multi-Window Support

Notifications

JIT/AOT Compilation

Quick Path to App Install

Doze on the Go

Background Optimizations

SurfaceView

Number Blocking

Call Screening

Locales and Languages

New Emojis

ICU4J APIs in Android

WebView

OpenGL ES 3.2 API

Key Attestation

Network Security Config

Default Trusted CA

APK Signature Scheme v2

Scoped Directory Access

Keyboard Shortcuts Helper

Custom Pointer API

So many things to cover in 60min Session

Chose my fight for today session

Android Compiler

Recent Google strategy seems to removing the old intermediary java bytecode .class all

together. why? Due to Google dispute with Oracle over use of Java?

Android Runtime

A journey that starts with Dalvik VM and now ends removing dalvik completely. Why Google

has to throw away its dalvik vm?

Webview

How it will impact the cross-platform development app? how to keep webview changes be

tested before it is released some easy option.

Android Compiler

Q: Why Android need a new compiler?

Benefits of Jack

Completely open source

Available in AOSP; partners are welcome to contribute.

Speeds compilation time

Jack has specific supports to reduce compilation time: pre-dexing,

incremental compilation and a Jack compilation server.

Handles shrinking, obfuscation, repackaging and multidex

Using a separate package such as ProGuard is no longer necessary.

Compilation Prior to Jack/Jill

Compilation with Jack/Jill

If we want to use Java 8 language feature set in Android then Jack toolchain

is must. Remember Android doesn’t support all Java 8 features as of now.

Jack is must for Java 8 language features

How to use Jack/Jill in Gradle for compilation

Known Issues

Instant Run does not currently work.

Tools that work on generated .class file would not work e.g

Lint detectors that operate on class files

Tools and libraries that require the app’s class files (such as instrumentation tests with

JaCoCo)

Switching the gear

Zareen is a pakistani restaurant in

Google Mountain View.

1477 Plymouth Street, Suite C

Mountain View, CA 94043

http://www.zareensrestaurant.com/

Android RuntimeDalvik Vs ART

Timeline

Prior to Kitakat 4.4, android OS has only dalvik as runtime.

In Kitkat 4.4, Google introduced ART alongside with Dalvik as an experiment

and let user select the runtime from developer options.

Timeline

Lollipop 5.0 ART completely replaced Dalvik. App become fast but

installation start taking time.

Marshmallow 6.0 ART some fixes.

Android N added Just in Time (JIT) compiler with code profiling to ART that

fixes app installation time problem.

Dalvik Vs ART(Android RunTime)

● Dalvik is JIT(Just in time compiler) that

translate app code into machine code

when the app is run.

● As you progress through the app,

additional code is going to be compiled

and cached, so that the system can reuse

the code while the app is running.

● It has a smaller memory footprint and uses

less physical space on the device

● ART, is AOT(Ahead of Time) compiler

that compiles the intermediate language,

Dalvik bytecode, into a system-

dependent binary.

● The whole code of the app will be pre-

compiled during install (once), thus

removing the lag that we see when we

open an app on the device.

● As ART runs app machine code directly

(native execution), it doesn't hit the CPU

as hard as just-in-time code compiling on

Dalvik

ART Some benchmark shared by android police

increased speed in CPU floating operations by approx. 20%

increased speed in RAM operations by approx. 10%

increased speed in storage operations by approx. 10

CPU integer operations - slight advantage goes to Dalvik

ART Downside

The code is pre-compiled at app install time, so the installation

process takes a bit longer.

The generated machine code requires more space than the existing bytecode

With Android N faster App installation and System Update

How?

Android N Hybrid RuntimeProfile-guided JIT/AOT Compilation

Android N Hybride Runtime with JIT/AOT

There won’t be any compilation during install, and applications can be

started right away, the bytecode being interpreted.

There is a new, faster interpreter in ART accompanied by a new JIT, but the

JIT information is not persisted.

The code is profiled during execution and the resulted data is saved. Later,

when the device is idle and charging, ART will perform a profile-based

compilation of the hot sections of the code, the rest remaining untouched.

While this procedure is still called AOT for simplicity, it can be read All-Of-

the-Time compilation.

Android N Hybride Runtime with JIT/AOT

Switching the gear

Silicon valley awakes early in the

morning

WebView

Why bother for WebView?

cross-platform framework Ionic, Sencha ,phonegapMake use of Webview

Multiprocess Webview

Multiprocess Architecture

Multiprocess Webview

Starting with Chrome version 51 in Android 7.0, WebView will run web

content in a separate sandboxed process when the developer option

"Multiprocess WebView" is enabled.

one of the benefits of multiprocess is the ability to run the renderer in 32-bit

to save memory even when webview is being used by a 64-bit app.

Javascript run before page load

Javascript context will be reset when a new page is loaded.

Currently, the context is carried over for the first page loaded in a new

WebView instance.

Developers looking to inject Javascript into the WebView should execute the

script after the page has started to load.

Geolocation on insecure origins

Geolocation API will only be allowed on secure origins (over HTTPS.)

This policy is designed to protect users’ private information when they’re

using an insecure connection.

Production problems of cross-platform appsDue to webview updates

Just like any native application, cross-platform apps usually have issues

when webview is changed with the release of OS sdk API.

The impact of webview changes has lot on cross-platform app, as the whole

app is running under webview. So webview is like OS for cross-platform

app.

How to test app with Webview Beta updates

Testing with Webview Beta

Testing with Webview Beta

Switching the gear

Silicon valley folks are casual and

funny.

Doze

Q:What does Doze mean?

Lets ask Google translator

What is Android Doze?

A system mode that

saves battery by deferring apps'

CPU and

network activities

when the device is idle

Doze on the Go

Doze introduced in Android 6.0 MarshMallow

Android 7.0, Doze takes a step further and saves battery while on the go.

Any time the screen is off for a period of time and the device is unplugged,

Doze applies a subset of the familiar CPU and network restrictions to

apps. This means users can save battery even when carrying their devices

in their pockets.

Android N Doze

Doze Restriction

Network access is suspended.

GCM messages are suspended. Only high-priority GCM messages are

delivered.

The system ignores wake locks.

Standard AlarmManager alarms (including setExact() and setWindow()) are

deferred to the next maintenance window.

The system does not perform Wi-Fi scans.

Conditions that exit Doze restriction

The user explicitly launches the app.

The app has a process currently in the foreground (either as an activity or

foreground service, or in use by another activity or foreground service).

The app generates a notification that users see on the lock screen or in the

notification tray.

When the user plugs the device into a power supply.

Can I Whitelist App from Doze?

An app that is whitelisted can use the network and hold partial wake locks

during Doze and App Standby.

However, other restrictions still apply to the whitelisted app, just as they do

to other apps. e.g the whitelisted app’s jobs and syncs are deferred (on API

level 23 and below), and its regular AlarmManager alarms do not fire.

User can whitelist app from Doze

Apps can request for whitelisting from Doze

An app can fire the ACTION_IGNORE_BATTERY_OPTIMIZATION_SETTINGS

intent to take the user directly to the Battery Optimization, where they can

add the app.

An app holding the REQUEST_IGNORE_BATTERY_OPTIMIZATIONS

permission can trigger a system dialog to let the user add the app to the

whitelist directly, without going to settings. The app fires a

ACTION_REQUEST_IGNORE_BATTERY_OPTIMIZATIONS Intent to trigger

the dialog.

How to test app against Doze

$ adb shell dumpsys battery unplug

$ adb shell am set-inactive <packageName> true

Questions