Andromance - Android Performance

{ AndromanceAndroid Performance

Optimization

O. Mert Şimşek /orhunmertsimsekmertsimsek.net4pps.co

Orhun Mert Şimşek

• Co-Founder & CEO of 4pps• Android & iOS Developer• Educational Responsible at

GDG Ankara• Android Evangelist

Let’s Boost the App

Use Splash If You Need

It is better to show a splash, instead of grotty progress bars

internal Getters & Setters?

Without a JIT, direct field access is about 3x faster than invoking a trivial getter. With the JIT (where direct field access is as cheap as accessing a local), direct field access is about 7x faster than invoking a trivial getter.*

(*): http://developer.android.com/training/articles/perf-tips.html

StrictMode

If you think that you might be doing some bad things accidentally, you should use StrictMode

It is commonly used to detect accidental network or disc access on the UI thread.

StrictMode

public void onCreate() { if (DEVELOPER_MODE) { StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder() .detectDiskReads() .detectDiskWrites() .detectNetwork() // or .detectAll() for all detectable problems .penaltyLog() .build()); StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder() .detectLeakedSqlLiteObjects() .detectLeakedClosableObjects() .penaltyLog() .penaltyDeath() .build()); } super.onCreate(); }

An example

DDMS

Use Hierarchy Viewer

You can determine layers and some performance stats of UI with this tool

Hard to use but very effective!

Use Hierarchy Viewer

Use Hierarchy Viewer

Use Less Objects, More Primitives

Creating an object is extremely: EXPENSIVE!

… but «primitive» is not!

Using a 2 different integer array is more efficient than using object arrays like fooBar(int,int)

badArray = new FooBar[] { new FooBar(5,8) , new FooBar(84,2) };

firstCoolArray = new int[] { 5, 84 };secondCoolArray = new int[] { 8 , 2 };

How to Search a 2D Array?

Search first for row, then column

TO DO

for (int i = 0; i < foo.length ; i++) {for (int j = 0; j < foo.length ; j++) {

process(foo[i,j]);}

}

NOT TO DO

for (int i = 0; i < foo.length ; i++) {for (int j = 0; j < foo.length ; j++) {

process(foo[j,i]);}

}

Use «Static» as Possible

It is 15% - 20%  faster!

And also use «static final» for your constants

Static variables are initialized only once , at the start of the execution.

«Lint» Usage

The lint tool checks your Android project source files for potential bugs and optimization improvements for correctness, security, performance, usability, accessibility, and internationalization. *

http://developer.android.com/tools/debugging/improving-w-lint.html

«Lint» Usage

In Eclipse it is easy to use, just one click!

In command line:

«lint [flags] <project directory>»

«lint myproject»

«lint --check MissingPrefix myproject»

Reusable Layouts

<include layout="@layout/titlebar"/>

It is commonly used for title bars, yes-no button panels etc.

Very easy to implement: Create a layout and use it in another layout with «<include ../>» tag

Do Your Hard-Work on Background Threads

It is forbidden to make network processes in main thread, since Android 3.0

How about Instagram? When you finished writing some hashtags and pressed to send button,

It had been posted just a while ago!

View Holder for ListView Objects

static class ViewHolder {  TextView text;  TextView timestamp;  ImageView icon;}

ViewHolder holder = new ViewHolder();holder.icon = (ImageView) convertView.findViewById(R.id.listitem_image);holder.text = (TextView) convertView.findViewById(R.id.listitem_text);…

A ViewHolder object stores each of the component views inside the ListView object, so you can immediately access them without the need to look them up repeatedly.

Smooth!

XML Drawables

PNG’s, JPG’s and others are big sized and a hard work for mobile device.

But creating an image with XML is very cheap and it is more efficient than you expected.

Using a 400 kb background image or using an Xml drawable which has size of just 300 bytes?

XML Drawables

<?xml version="1.0" encoding="UTF-8"?><shape  xmlns:android="http://schemas.android.com/apk/res/android"  android:shape="rectangle">  <stroke    android:width="3dp"    android:color="#000000" />  <gradient    android:endColor="#F5CD7A"    android:startColor="#657892"    android:angle="90" /></shape>

Handling Overdraws

The most important part of performance. – If you ask me!

Since Android 4.2, we can see overdraws in our devices.

Overdraw is simply, drawing a pixel more than once.

It’s notation is also simple:

• No color: No overdraw• Blue: 1x overdraw (pixel is drawed 2 times)• Green: 2x overdraw• Light Red: 3x overdraw• Dark Red: 4x or more overdraw (ALERT!)

Handling Overdraws

SpotifyYoutube

• Acceptable red areas

• Mostly blue and green

• Optimized by Romain Guy - The God of Android Performance Optimization

• JUST red areas

• Whole screen is drawed more than 5 times

• Probably haven’t checked for overdraws

Handling Overdraws

How to avoid?

Actually its secret is written at the last one

• thumbnail.setBackgroundColor(0x0);• android:windowBackground="@null"• If a view will not used anymore, don’t make its visibility «INVISIBLE»,

make it «GONE»• And use a simple design!

Summary and Little Other Tips

Do use two parallel «int» arrays instead of array of objects (int,int) Do use «primitive» instead of objects Do use as possible as «static» methods Do use «static final» for constants Do use foreach instead of for Do use as possible as Xml Drawables instead of images (jpg,png)

Don’t create unnecessary objects Don’t allocate memory if you can work without it Don’t use getters and setters inside the class Don’t do your hard works on main thread

and the most important one: Don’t publish your app unless it doesn’t have performance problems!

Torment Is Over, That’s All!

Thanks for listening!

O. Mert Şimşek /orhunmertsimsekmertsimsek.net