Google DevFest '17 | App shrinkage with ProGuard | Gradle Build System

Talk delivered at GDG DevFest'17 on 29th Oct '17.
I talk about leveraging the proguard rules to go the extra mile to shrink your APK.

Transcript

1. Ishan Guliani VP Engineering @ Applop | Former GSA Certified Software Product Manager Certified Mobile Applications Engineer /ishanguliani Shrink it down, Scale it up : Android APKs
2. By the end of the session ? • Remove some extra bytes • Get insight into the build system • Explore shrinkage options • Feel confident
3. The steps • Semi tech • Sample code run through • 11 to 7 effect -- (11 MB to 7MB)^n
4. Why Shrink ?
5. Why Shrink ?
6. Key terms to note : - • Project level build file • Proguard ◦ optimizes the bytecode ◦ removes unused code instructions ◦ Obfuscates the remaining classes, fields, and methods with short names. • Dex class files have 64K reference limit • APK Analyser • APK comparison • Product flavors
7. It all starts from the build.gradle (module) android { ... buildTypes { release { minifyEnabled true proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' } } productFlavors { flavor1 { } flavor2 { proguardFile 'flavor2-rules.pro' }...
8. Default configuration
9. Credits : Ahmad S and Kazim Ali
10. Classes get leaved out when • When your app references a class only from the AndroidManifest.xml file • When your app calls a method from the Java Native Interface (JNI) • When your app manipulates code at runtime (such as with reflection or introspection)
11. Keep classes in the code -keep public class MyClass
12. Keep classes in the code -keep public class MyClass THINK FIREBASE
13. Keep classes in the code Adding the following line to proguard-rules.pro saves firebase POJO from being removed during shrinking --
14. Example
15. Where to go from here... • Explore advanced optimisations with proguard-android-optimize.txt • Study gradle plugin configurations available • Feel more confident about deploying production builds
16. Thanks! Ishan Guliani /ishanguliani Chat with me - Startup pitches | Early stage tech stack