Android is going to Go!Android and golang

Who are you?

@AlmogBaku on github

1. A serial entrepreneur

2. Co-Founder & CTO @ Rimoto

3. Developer for 12 years

4. GitHub addicted.

5. Blog about entrepreneurship and

development:

www.AlmogBaku.com

What is Rimoto?

Rimoto enable apps to sponsor their user’s mobile-data, and

to became accessible for international travellers,

regardless their data-plan, boosting their engagement.

What are we going to talk about?

1. What is Go?

2. How can we use Go with Android?

3. When is it useful?

Disclaimer

You wanna know more? Google it!

Google tip: use the keyword “golang”

Who heard about Go?

Why use Go, and what is it?!

• New modern language (since 2009)

• Super fast (native) compiling

• Concurrent

• Performant

• Garbage collected

• Standard libraries

Hello worldpackage main

import "fmt"

func main() { fmt.Println("Hello DroidCon!")}

RUN

Goroutinesfunc boring() { for i := 0; i < 10; i++ { sayIt(i) }}

func sayIt(i int) { time.Sleep(time.Duration(rand.Intn(1e3)) * time.Millisecond) fmt.Println("I'm saying ", i)}

RUN

Goroutinesfunc not_boring() { for i := 0; i < 10; i++ { go sayIt(i) } time.Sleep(2 * time.Second)}

func sayIt(i int) { time.Sleep(time.Duration(rand.Intn(1e3)) * time.Millisecond) fmt.Println("I'm saying ", i)}

RUN

Goroutines syncing / WaitGroupfunc not_boring_at_all() { wg := sync.WaitGroup{} wg.Add(10)

for i := 0; i < 10; i++ { go sayIt(i, &wg) }

wg.Wait()}

func sayIt(i int, wg *sync.WaitGroup) { defer wg.Done()

time.Sleep(time.Duration(rand.Intn(1e3)) * time.Millisecond) fmt.Println("I'm saying ", i)}

RUN

Goroutines communications / Channelspackage main

import "fmt"

func main() { c := make(chan string)

for i := 0; i < 5; i++ { go func() { c <- "ping" }() } for i := 0; i < 5; i++ { go func() { c <- "pong" }() }

for i := 0; i < 10; i++ { fmt.Println(<-c) }}

RUN

Standard librariespackage main

import ( "fmt" "net/http")

func handler(w http.ResponseWriter, r *http.Request) { fmt.Fprintf(w, "Hi there!")}

func main() { http.HandleFunc("/", handler) http.ListenAndServe(":8080", nil)}

Go Mobile

A tool for using Golang for native mobile apps easily!

Caution

The Go Mobile project is experimental. Use this at your own risk.

Why?

1. Full-stack development

2. Write a single cross-platform Go library

3. Bring a simple and modern language

and development tooling to mobile

4. Enjoy Go benefits of native, faster, and

much more concurrent code

How?

Native Apps● Write the whole app in Go (with OpenGL)

● Use Go packages for graphics, event handling, audio, etc.

● When Native App UI is not required (i.e. games)

SDK Apps● Write common functionality in

Go, as a library

Native Go Apps

• 100% Go app

• Multi platform: Android, iOS and Desktop

• GUI with OpenGL

Behind the scenes

NativeActivityAndroid

App

Gomobile

A tool that automate this process– Toolchain installation

– Creating NativeActivity

– Attach the Go runtime to the app

– Bind the App binary to the app

– Multi Architecture build

– Cross platform(Android/iOS) build

$ gomobile build golang.org/x/mobile/example/basic

$ gomobile install golang.org/x/mobile/example/basic

DEMO

SDKs

• Build the app natively with Java/Swift/Obj. C

• Write a simple regular Go library

• Reuse libraries across platforms and projects

Common library

iOS

Android

Backend service A

Backend service B

3rd party

Behind the scenes

JNIAndroid

App

Go shared binary

rpc

Behind the scenes

package mypkg

func Hello() (string, error) { return "Gopher", nil }

public abstract class Mypkg {

public static String hello() throws Exception { ... }

}

Go Library:

Java API:

Gomobile

A tool that automate this process

– Multi Architecture build

– Build as shared library

– Automatically generate the binding for Java/Swift/Obj. C

– Bundle everything to an .aar

– Cross platform(Android/iOS) build

$ gomobile bind -target=android golang.org/x/mobile/example/bind/hello

DEMO

Disadvantages

Nothing is perfect..• .aar includes all architecture binaries (increase size)• go binaries are currently statically linked• Go as a native app is lack of many sensors and

integrations with the Android/iOS APIs• The communication between the Platform and the go

binary is not free

Questions?

Thanks.@AlmogBaku