Android Performance Optimization presentation which is told on @ DevFest Ankara 2013, @ DevFest Eskişehir 2013, @ DevFest Konya 2014, @DevFest İstanbul 2014

1. { Andromance
Android Performance Optimization
O. Mert Şimşek
/orhunmertsimsek
mertsimsek.net
4pps.co

2. Orhun Mert Şimşek
• Co-Founder & CEO of 4pps
• Android & iOS Developer
• Educational Responsible at
GDG Ankara
• Android Evangelist

3. Let’s Boost the App

4. Use Splash If You Need
It is better to show a splash, instead of grotty progress bars

5. 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

6. 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.

7. 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

8. DDMS

9. Use Hierarchy Viewer
You can determine layers and some performance
stats of UI with this tool
Hard to use but very effective!

10. Use Hierarchy Viewer

11. Use Hierarchy Viewer

12. 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 };

13. 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]);
}
}

14. Use «Static» as Possible
It is 15% - 20% faster!
Static variables are initialized only once , at the start of
the execution.
And also use «static final» for your constants

15. «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

16. «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»

17. Reusable Layouts
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
<include layout="@layout/titlebar"/>

18. 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!

19. View Holder for ListView Objects
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.
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);
…
Smooth!

20. 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?

21. 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>

22. 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!)

23. Handling Overdraws
Youtube Spotify

24. • Acceptable red areas
• Mostly blue and green
• Optimized by Romain Guy -
The God of Android
Performance Optimization

25. • JUST red areas
• Whole screen is drawed
more than 5 times
• Probably haven’t checked
for overdraws

26. 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!

27. 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!

28. Torment Is Over, That’s All!
Thanks for listening!
O. Mert Şimşek
/orhunmertsimsek
mertsimsek.net