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

Agenda • Effective Java in Android • Layouts and UI • Proper Use of Resources • Dev Tools and Measuring Performance 2 

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) 3 

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 4 

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 5 

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 6 

“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+) 7 

GridLayout example 8 

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 9 

Splash Screen Effect 10 

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. 11 

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+] 12 

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 

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

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) 15 

Gradle Plugin: APK splits android { ... splits { density { enable true reset() exclude "ldpi", "tvdpi", "xxxhdpi" } } 16 WARN: you will need to set different version code for each APK file 

Developer Options On Your Device 17 

Developer Options On Your Device 18 

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 19 

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 20 

LeakCanary 21 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); } } 

LeakCanary 22 * Sometimes you still need MAT 

In-app performance check • StrictMode • Google’s profiling tools: Traceview & dmtracedump • Hugo by Jake Wharton • Tools like NewRelic to show bottlenecks in response time 23 

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  24 

Thank you! @sergiizhuk [email protected] http://ua.linkedin.com/in/sergiizhuk 25