В докладе пойдет речь о простых, но далеко не всем известных приёмах оптимизации приложений и повышения продуктивности разработчика. Будут рассмотрены такие темы : Effective Java в Android Оптимальное использование файлов ресурсов Правильная работа с лейаутами - Отзывчивый UI Настройка инструментов разработчика и эмуляторов Полезные ссылки и тематические ресурсы

1. Android Performance Tips & Tricks
Sergii Zhuk
Android Developer at DAXX BV
Kyiv, FrameworksDays Android Saturday, 2015-06-06 1

2. Agenda
• Effective Java in Android
• Layouts and UI
• Proper Use of Resources
• Dev Tools and Measuring Performance
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3. Effective Java in Android
• Avoid using Floating-Point
• Prefer primitives and primitive-backed data
structures (ArrayMap, SparseArray)
• Two parallel (int) arrays are better than array
(int,int)
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4. Effective Java in Android
• System.arraycopy() is about 9x faster than a
hand-coded loop
• Make your method static: invocations will be
about 15%-20% faster
• Do not use Enums
WAT??
 @IntDef annotation
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5. Supplying Scaled Drawables
• Why not to supply a single xhdpi image as blurred
background for the screen?
• Rendering performance will decrease because
device should scale your image during app
execution
• Such operation requires extra memory for Bitmap
native processing, potential source of
OutOfMemoryError
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6. Make Your Layouts Flat
• Inflating layout is a top-down traversal of the
view tree
• Hierarchy Viewer (Android SDK) allows to
analyze layout while your application is
running
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7. “Heavy” ViewGroups
• RelativeLayout requires two measurement passes to
ensure that it has handled all of the layout relationships
• The same is valid for LinearLayout with layout weights
• If one of the children of ViewGroups shown above is again
RelativeLayout or LinearLayout with weights – four
measurements passes will be required for sub-hierarchy
• GridLayout could be good solution in some cases (API 14+)
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8. GridLayout example
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9. Splash Screen Effect
• Show a blank window constructed with the
application theme, including specified
background drawable while application is
starting
• Behavior is provided by OS
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10. Splash Screen Effect
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11. ViewStub
• A lightweight view with no dimension and
doesn’t draw anything or participate in the
layout
• Use ViewStub as a “lazy include” for sub-
hierarchies that can be optionally inflated
later.
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12. Develop for the Low End
• Devices distribution in the world
• Most of users could have lower-end devices
than yours
• Use ActivityManager.isLowRamDevice() to
detect if device in the class of a 512MB RAM
and/or about a 800x480 screen [API 19+]
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13. 13
Develop for the Low End
* More details at my Stackoverflow.com question
Nexus 4 (Genymotion emu)
and other devices
Lenovo P780 with Android 4.2.1

14. Remove unused resources
• Lint (Android SDK): will highlight these resources
• Android-resource-remover (consumes Lint
output)
• Gradle:
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buildTypes {
release {
minifyEnabled true
shrinkResources true
}
}

15. Multiple APKs on Play Store
• Different APKs for your app that are each
targeted to different device configurations
• Have same app listing on Google Play and must
share the same package name and be signed with
the same release key
• Recommended to use multiple APKs only when
your APK is too large (> 50MB)
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16. Gradle Plugin: APK splits
android {
...
splits {
density {
enable true
reset()
exclude "ldpi", "tvdpi", "xxxhdpi"
}
}
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WARN: you will need to set different version code for each APK file

17. Developer Options On Your Device
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18. Developer Options On Your Device
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19. Avoid Requesting a Large Heap
• Requesting a larger heap may be necessary in
some rare situations like media content
• android:largeHeap=“true” result: less memory
to be available for other apps, necessitating
them being killed and restarted
• android:largeHeap seems to be not enough
documented
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20. Memory Leaks
• If a chain of references holds an object in
memory after the end of its expected lifetime
• Old approach:
Dump  Fix header  MAT  Find leak
• New approach: LeakCanary will notify you
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21. LeakCanary
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dependencies {
debugCompile 'com.squareup.leakcanary:leakcanary-android:1.3.1'
releaseCompile 'com.squareup.leakcanary:leakcanary-android-no-op:1.3.1'
}
public class ExampleApplication extends Application {
@Override public void onCreate() {
super.onCreate();
LeakCanary.install(this);
}
}

22. LeakCanary
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* Sometimes you still need MAT

23. In-app performance check
• StrictMode
• Google’s profiling tools: Traceview &
dmtracedump
• Hugo by Jake Wharton
• Tools like NewRelic to show bottlenecks in
response time
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24. References
• http://developer.android.com/training/articles/perf-tips.html
• Chet Haase at Medium: Developing for Android (parts 1-5)
• Memory leaks in Android (in Russian)
• Android Performance Case Study by Romain Guy
• Is Android layout really exponentially hard? SO discussion
• Pro Android Apps Performance Optimization by Herv Guihot
• Eric Lafortune talk on MCE2015 Conference
• Cyril Mottier blog
• Taylor Ling blog
• Romain Guy blog
• Android Performance Patterns (YouTube and G+)
• DOU.ua Android Digest 
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25. Thank you!
@sergiizhuk
sergey.public@gmail.com
http://ua.linkedin.com/in/sergiizhuk
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