Effective Android Development

EFFECTIV E

ANDROID

DEVELOPMENT

S E R G I I Z H U K @ D R O I D C O N B E R L I N

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HELLO!

My name is Sergii Zhuk

• Android Developer @ Zalando SE

• Author of Android Digest for Ukrainian Developers Community

• In Berlin since August 2015

• twitter.com/sergiizhuk

• medium.com/@sergii

http://www.twitter.com/sergiizhuk

http://www.twitter.com/sergiizhuk

https://medium.com/@sergii


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ZALANDO SE

• Europe’s leading online fashion platform

• ~ 10,000 employees in Europe

• ~ EUR 3bn revenue in 2015

• ~ 60% of shop traffic came from mobile

• 10M+ downloads Android app

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AGENDA

• Android Studio

• Test Devices

• Dev & Environment

• Gradle Hacks

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ANDROID STUDIO

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ANDROID STUDIO – T IP 1

How does your manifest really look like?

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How does your manifest really look like?

• Manifest Merger

See also: “Hey, Where Did These Permissions Come From?” on The CommonsBlog

https://commonsware.com/blog/2015/06/25/hey-where-did-these-permissions-come-from.html

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You need to use new Android APIs. Are there any examples?

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You need to use new Android APIs. Are there any examples?

• Find Sample Code

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“I’m not gonna to commit right now…”

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“I’m not gonna to commit right now…”

Local history for rescue!

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Support Annotations are your friends

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Support Annotations are your friends

• Metadata annotations you can decorate your code with, to help catch bugs

• @VisibleForTesting, @Nullable, @AnyThread, @Keep, @StringRes etc.

• Integrated with Android Studio & Lint

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How to make a code review?

Switch between branches could be slow:

•stash your changes

•checkout branch

• reload gradle config

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How to make a code review?

• Launch two IDE instances: one for the review, another one for the main work

• Yes, you will need a powerful machine

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Apply changes fast

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Swap code fast

• Instant Run

• JRebel

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Swap code fast

• How changes are handled

• Immediately (Hot swap)

• Activity restart (Warm swap)

• Application restart (Cold swap)

• Rebuild

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Swap code fast

Change Instant Run JRebel

Change code of the existing method Could be immediately Activity restart

Change/remove resource Activity restart Activity restart

Method or class signature, statics, annotations App restart, API 21+ Activity restart

Add/Remove superclass, implemented interface App restart, API 21+ App restart

Change Manifest or notification resource Rebuild Rebuild

Sources: https://developer.android.com/studio/run/index.html#instant-run

Reto Meier "Instant Run: How Does it Work?!"

Oleg Selajev "Looking at JRebel for Android and Instant Run ..."

https://developer.android.com/studio/run/index.html#instant-run




https://goo.gl/mEP7N5



https://goo.gl/NvFHpN







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TEST DEVICES

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TEST DEVICES – T IP 1

A lot of UI issues could be discovered if compare app on Lollipop and pre-Lollipop

devices

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A lot of UI issues could be discovered if compare app on Lollipop and pre-Lollipop

devices

• Use at least two emulator instances or devices during dev tests

• Use both 4.* and 5+ OS versions

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Emulators question

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Emulators question

Genymotion

• Free only for private use & limited functionality

• Latest OS version with the delay

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Emulators question

Genymotion

• Free only for private use & limited functionality

• Latest OS version with the delay

New Android SDK Emulator

• push apps/data 10x faster than to a device

• includes Google Play Services built-in

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(Cloud) Test Platforms

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• Can execute scenarios (Espresso tests, Robotium etc.)

• Can take screenshots, measure device metrics, track logs

• Example: AWS Device Farm, TestDroid, Firebase Test Lab

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• Also you can create your own device farm

• Open-source tools available like Square Spoon

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DEV & ENVIRONMENT

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DEV & ENVIRONMENT – T IP 1

Measure execution time

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Measure execution time

• Hugo by Jake Wharton

@DebugLog

public String getName(String first, String last) {/* ... */}

V/Example: --> getName(first="Jake", last="Wharton")

V/Example: <-- getName [16ms] = "Jake Wharton"

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How to read logcat output from your device?

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How to read logcat output from your device?

• Jake Wharton’s pidcat

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Click on device/emulator screen every time you are testing some functionality

• BUT what if you have 5 test devices?

• AND you have a regression plan for 30 scenarios?

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• Use ADB commands/scripts to replace manual interactions

adb shell input keyevent 4

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DEV & ENVIRONMENT – T IP 3 .5


• Use adb-ninja script to submit your command to several devices simultaneously

https://github.com/romannurik/env/blob/master/bin/ninja-adb






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Think about application tracking & analytics

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Think about application tracking & analytics

• A lot of projects with overlapping functionality:

• Google Analytics

• Firebase Analytics

• Adjust

• Answers Events by Fabric

• Integration requires huge architecture effort

• Testing is always hard

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Network output logging/analyzing?

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Network output logging/analyzing

Use Http Monitoring & Proxy tools like Charles

• HTTP/HTTPS traffic monitoring

• Rewrite values

• Set breakpoints

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All-in-one inspection tool by Facebook?

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All-in-one inspection tool by Facebook!

• Stetho

• SQLite database

• Network proxy

• Hierarchy Viewer

• App preferences

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Explore your APK

• Manifest

• Method count per dependency

• Resources set properly

• and more

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Explore your APK:

ClassyShark

• DEX Method count by package/class

• Dependencies

• Merged Manifest

• Obfuscation check

Android Studio APK Analyzer

+ Drawables preview

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GRADLE HACKS

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GRADLE HACKS – T IP 1

Check your config

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Check your config

build.gradle:

• Get rid of mavenCentral, use jcenter

• Check Gradle plugin version

• DON’T specify version ranges for the dependencies

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Check your config

• gradle.properties:

org.gradle.daemon=true

# if multiple modules [incubating feature]

org.gradle.parallel=true

# Dex In Process. Also set in build.gradle dexOptions{ javaMaxHeapSize }

org.gradle.jvmargs=-Xmx4096m

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How much time spent on building the app?

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How much time spent on building the app?

• Track your time! https://github.com/passy/build-time-tracker-plugin

https://github.com/passy/build-time-tracker-plugin








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Build faster using target API 21 for dev needs

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Build faster using target API 21 for dev needs

productFlavors {

// Define separate dev and prod flavors

dev21 { minSdkVersion 21 }

dev14 { minSdkVersion 14 }

prod {

// The actual minSdkVersion for the application

minSdkVersion 14

}

}

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CONCLUSION

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CONCLUSION

• Keep optimizing time spent on repeating things

• Keep looking for ways how to build the app faster

• It’s never too late to improve tools knowledge

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THANKS!

• tech.zalando.com/jobs

• @sergiizhuk

• medium.com/@sergii

https://tech.zalando.com/jobs/

https://www.twitter.com/sergiizhuk

https://www.twitter.com/sergiizhuk



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Effective Android Development