Optimizing Your Apps For Emerging Markets

#DroidconMtl

+VinayGaba@vinaygaba

Emerging MarketsDrive Growth

Source: Mediacells via The Guardian

Source: Mediacells via The Guardian

44

36

21

5137

11

80

109

25

66

9

Smartphone Feature phone Multimedia phone

Brazil Russia

India China

1. Optimizing App Size

The smaller, the better

Color Filters

Use Color Filter

• Faster way to experiment with color schemes.• Reduce the number of assets, which in turn reduces

the apk size.• Less memory used as the number of assets are

reduced.

Code

ImageView redCircle = (ImageView) findViewById(R.id.circle_red_imageview); ImageView greenCircle = (ImageView) findViewById(R.id.circle_green_imageview); ImageView blueCircle = (ImageView) findViewById(R.id.circle_blue_imageview); // we can create the color values in different ways: redCircle.getDrawable().setColorFilter(Color.RED, PorterDuff.Mode.MULTIPLY ); greenCircle.getDrawable().setColorFilter(0xff00ff00, PorterDuff.Mode.MULTIPLY ); blueCircle.getDrawable().setColorFilter(getResources().getColor(R.color.blue),PorterDuff.Mode.MULTIPLY );

Image Optimizatio

nsColor Filters

JPEG WEBP PNG GIF

Lossy

Lossless

Transparency

Animation

WebP

No Noticeable Change

PNG24 kb

WebP10 kb

Compatibility

• You can use the native WebP decoder on 4.2 and later.• For lower versions, use libpng to convert to PNG

format and then use it in the app.

Other Libraries

• Use programs like OptiPNG, TruePNG and PNGCrushto significantly reduce the size of PNG images.• Use mozjpeg for jpeg images.• 5-10% size reduction

• Won’t cause any visible changes to the images.

Remove Unused Content

Image Optimizatio

nsColor Filters

Remove Unused Content

• Use Resource Shrinking.

Code

android { ... buildTypes { release { minifyEnabled true shrinkResources true proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' } } }

Remove Unused Content

• Use Resource Shrinking.• Use tools like Lint and ProGuard.• Use Android-Unused-Resources jar file if you are

still using Eclipse.

https://code.google.com/p/android-unused-resources/

2. Optimizing NetworkCalls

Expensive Data

Flaky Networks

Challenges

Build for Failure

Most efficient way to transfer is to not transfer

Image Scaling

Appropriate Image Size

• Store multiple image sizes on the server• Low-res devices might never need a full resolution

image• Most times the smallest image size is sufficient.

ChecksumImage Scaling

Client A Client BServer

Checksum

ID

Send File ID

Transfer File

CS ID

Code

public static String getMD5EncryptedString(String encTarget){ MessageDigest mdEnc = null; mdEnc = MessageDigest.getInstance("MD5"); // Encryption algorithm mdEnc.update(encTarget.getBytes(), 0, encTarget.length()); String md5 = new BigInteger(1, mdEnc.digest()).toString(16); while ( md5.length() < 32 ) { md5 = "0"+md5; } return md5; }

Checksum

• Avoid transfers as much as possible.• For file transfers, first compute the md5 checksum

and send it to the server to check if it already existson the server. • The cost to upload the entire file again can be

avoided.

Image Scaling Checksum Transfer in

Blocks

Transfer in blocks

• Do data transfers in blocks.• Keep track of the blocks that have been transferred

and yet to be transferred.• The block size can vary based on the type of

connection.

Testing for different networks is a pain

Testing for different networks

• Facebook recently open-sourced Augmented Traffic Control (ATC).• It is a tool to simulate network conditions.• It can simulate 2G, Edge, 3G, and LTE networks.• Has multiple profiles for a lot of different countries.

http://facebook.github.io/augmented-traffic-control/

3. Optimizing for DifferentPhones

Small Screens

Slow Processing

Challenges

Developing for flagshipdevices is easy

Year Class

Code

int year = YearClass.get(getApplicationContext()); if (year >= 2013) { // Do advanced animation} else if (year > 2010) { // Do simple animation } else { // Phone too slow, don't do any animations}

https://github.com/facebook/device-year-class

RedesignYear Class

Redesign

• Remove features from low-end devices if they won’thave the best user experience.• This could be animations, videos or even

functionalities.• No feature >>> Bad feature

@vinaygaba

Questions?