cosmictaserdev-creator/convx/android-performance-skill

Android Performance Optimization Skill

Quick Domain Index

Load the relevant reference file(s) based on the user's query. Multiple may apply.

Response Philosophy

1. Diagnose first — Ask for or infer: device API level, whether it's debug/release, reproduction steps, any stack traces or Play Console data. Don't prescribe fixes before understanding root cause.
2. Show, don't just tell — Always include concrete Kotlin/Java code examples, not just advice.
3. Layered recommendations — Start with the highest-impact, easiest fix. Then go deeper.
4. Measurability — Every recommendation should include how to measure before/after (tooling, metrics).
5. Trade-offs — Be honest about trade-offs (e.g., aggressive caching vs memory pressure).

Universal Performance Principles (always applicable)

• Never block the main thread. The Main/UI thread must complete each frame in <16ms (60fps) or <11ms (90fps). Any I/O, computation, or IPC on it causes jank or ANRs.
• Measure before optimizing. Gut feelings are wrong. Profile first.
• Understand the Android lifecycle. Most performance bugs come from misusing Activity/Fragment/ViewModel lifecycles.
• Release builds behave differently. Always validate performance on a release build with minification enabled.
• Real devices matter. Emulators don't replicate thermal throttling, low-RAM behavior, or GPU differences.

Common Entry Points & Triage

"My app has ANRs in Play Console"

→ Read references/anr.md Key questions: What's the ANR type? (Input dispatch timeout / Service timeout / Broadcast timeout). Load the ANR traces from Play Console and look for the main thread stack.

"My app is crashing"

→ Read references/crashes.md Key questions: Is it OOM, a NullPointer, or another exception? Is it reproducible? Is there a stack trace?

"Cold start is too slow"

→ Read references/startup.md Key questions: What is the current TTID? Are you using Jetpack App Startup? Is Application.onCreate() doing heavy work?

"My UI is janky / laggy"

→ Read references/ui-rendering.md Key questions: Is it in a list (RecyclerView)? Is it on scroll? Is GPU overdraw visible? What does the frame timeline in Android Studio show?

"My app uses too much memory / has leaks"

→ Read references/memory.md Key questions: Is LeakCanary showing leaks? Is it OOM on low-RAM devices? Are you loading large Bitmaps?

"Battery drain complaints"

→ Read references/battery.md Key questions: Is the app running background services? Using wakelocks? Frequent network polling?

Baseline: Always Recommend These

Regardless of the specific issue, the following should always be in place:

// 1. StrictMode in debug builds - catches main thread violations early
if (BuildConfig.DEBUG) {
    StrictMode.setThreadPolicy(
        StrictMode.ThreadPolicy.Builder()
            .detectAll()
            .penaltyLog()
            .build()
    )
    StrictMode.setVmPolicy(
        StrictMode.VmPolicy.Builder()
            .detectLeakedSqlLiteObjects()
            .detectLeakedClosableObjects()
            .detectActivityLeaks()
            .penaltyLog()
            .build()
    )
}
 
// 2. Use Baseline Profiles (in release) for faster startup JIT/AOT
// See references/build-size.md
 
// 3. Use Android Vitals in Play Console for real-world data
// ANR rate, crash rate, slow start rate, slow frames

Metrics Reference (know your targets)