Optimize for Android (Go edition) : Lessons from Google apps Part 2

Posted by Niharika Arora, Developer Relations Engineer

Building for Android Go involves paying special attention to performance optimizations and resource usage.

In part-1 of this blog, we discussed why developers should consider building for Android Go, some tips on optimizing the app memory and identified the standard approach to follow while fixing performance issues. In this blog, we will talk about the other vitals to pay attention to while building apps for Android Go.

Optimize your apps for Android Go

Improve startup latency

Improving app startup time requires a deep understanding of things that affect it.

• Avoid eager initialization: Avoid doing eager work that may not be needed in your app’s startup sequence. The user launching your app is the most well-known reason a process starts, but WorkManager, JobScheduler, BroadcastReceiver, bound Services, and ContentProviders can also start your app process in the background. Avoid initializing things eagerly in your Application class like ContentProviders, or androidx initializers if possible (If they are not needed for any possible reason for your app process to start).

• Move the tasks from UI thread to background thread

• Identify operations which occupy large time frames and can be optimized.
• Identify operations that consume more time than expected.
• Identify operations which cause the main thread to be blocked.

If there are tasks which are taking longer and blocking the main thread, try to move them to a background thread or prefer using WorkManager. 

• Check third party library initialization 

Lazy load third party libraries. A lot of libraries do have on demand initialization or disabling auto init options.

• Check rendering time of webp / png images
• Prefer webp images over jpg/png
• Prefer svg for small icons.
• Check if any layouts are invisible, but still spend time for the images to be loaded.
• Explore using a low resolution image according to the memory capabilities of the device.
• Remove unnecessary backgrounds/alpha from views.

Identify and measure these transactions to understand :

a.    Don’t translate internal-only UI strings. Mark them as translatable = “false”. 

  

b.    Remove unused alternative resources: You can use the Android Gradle plugin's resConfigs property to remove alternative resource files that your app does not need. if you are using a library that includes language resources (such as AppCompat or Google Play Services), then your app includes all translated language strings for the messages in those libraries whether the rest of your app is translated to the same languages or not. If you'd like to keep only the languages that your app officially supports, you can specify those languages using the resConfig property. Any resources for languages not specified are removed. 

The following snippet shows how to limit your language resources to just English and French

android {     defaultConfig {         ...         resConfigs "en", "fr"     } }

You can read more here.

c.    Don’t translate what doesn’t need translation: If the string does not participate in a UI, it should not be translated. Strings for the purpose of debugging, exception messages, URLs and so on should be string literals in code, not resources. 

i.    Don’t translate what’s not shown to the user anyway

It’s possible to have a String resource that’s practically never shown to the user, but is still strongly referenced. One example is in your <activity>, if you have an android:label set and referencing a String resource but the Activity’s label is never actually shown (e.g. it’s not a launcher Activity and it doesn’t have an app bar that shows its own label).

  

 d.    Don’t translate URLs:  Consider this example:

<string name="car_frx_device_incompatible_sol_message"> This device doesn\'t support Android Auto.\n <a href="https://support.google.com/androidauto/answer/6395843">Learn more</a> </string>

You may recognize < and > - these are escape characters for “<” and “>”. They’re needed here because if you were to put an <a> tag inside a <string> tag, then the Android resource compiler would just drop them (as it does with all tags it doesn’t recognize).

However, this means that you’re translating the HTML tags and the URL to 78 languages. Totally unnecessary.

Instead, remove the part with HTML:

<string name="car_frx_device_incompatible_sol_message"> This device doesn\'t support Android Auto. </string>

Note we don’t define a separate string for “Learn more”, because it’s a common string. To produce the HTML snippet for the link, we define "<a href="https://support.google.com/androidauto/answer/6395843>%s</a>" as a string literals in code, and then drop the value of “Learn more” from resources into the format specifier.

e.    Inline untranslated strings: By specifying strings in strings.xml you can leverage the Android framework to automatically change the actual value used at runtime based on the current configuration (e.g. based on the current locale, show a localized value for the string).    

f.    Remove duplicate strings: If you have the same string multiple times as a literal in code (“Hello World”), it will be shared across all instances. But resources don’t work this way - if you have an identical string under a different name then unless both are translated identically across 78 languages (unlikely) you’ll end up with duplicates.

Don’t have duplicate strings!  

g.    Don’t have separate strings for ALL CAPS or Title Case: Android has built-in support for case mutations. 

Use android:capitalize (since API level 1). If set, specifies that this TextView has a textual input method and should automatically capitalize what the user types. The default is "none".