Bobby Prabowo

Bopbi’s mind

I’m Bobby, an Android Dev and (still) an app hobbyist

Current Project

Recent TIL

claude code AWS Bedrock settings sample for multi model declaration

Date: 2026/09/06

example of claude code settings.json that declare multiple version of model (generated by fable 5.1 and using fake application inference profiles)

{
  "model": "arn:aws:bedrock:ap-northeast-1:123456789012:application-inference-profile/g7h8i9j0k1l2",
  "awsAuthRefresh": "aws sso login --profile your-profile",
  "env": {
    "CLAUDE_CODE_USE_BEDROCK": "1",
    "AWS_PROFILE": "your-profile",
    "AWS_REGION": "ap-northeast-1",
    "ANTHROPIC_DEFAULT_OPUS_MODEL": "arn:aws:bedrock:ap-northeast-1:123456789012:application-inference-profile/a1b2c3d4e5f6",
    "ANTHROPIC_DEFAULT_SONNET_MODEL": "arn:aws:bedrock:ap-northeast-1:123456789012:application-inference-profile/g7h8i9j0k1l2",
    "ANTHROPIC_DEFAULT_HAIKU_MODEL": "arn:aws:bedrock:ap-northeast-1:123456789012:application-inference-profile/m3n4o5p6q7r8"
  },
  "modelPicker": {
    "replaceBuiltInOptions": true,
    "options": [
      {
        "model": "arn:aws:bedrock:ap-northeast-1:123456789012:application-inference-profile/a1b2c3d4e5f6",
        "label": "Opus 4.8",
        "description": "Complex reasoning"
      },
      {
        "model": "arn:aws:bedrock:ap-northeast-1:123456789012:application-inference-profile/s9t0u1v2w3x4",
        "label": "Opus 4.6"
      },
      {
        "model": "arn:aws:bedrock:ap-northeast-1:123456789012:application-inference-profile/g7h8i9j0k1l2",
        "label": "Sonnet 4.6",
        "description": "Daily coding"
      },
      {
        "model": "arn:aws:bedrock:ap-northeast-1:123456789012:application-inference-profile/y5z6a7b8c9d0",
        "label": "Sonnet 4.5"
      },
      {
        "model": "arn:aws:bedrock:ap-northeast-1:123456789012:application-inference-profile/m3n4o5p6q7r8",
        "label": "Haiku 4.5",
        "description": "Fast, lightweight tasks"
      }
    ]
  }
}

Benchmark Gist

Date: 2025/10/07
// module: benchmark
// androidx.benchmark:benchmark-macro + benchmark-junit4
class MapperBenchmark {
    @Test fun mapList_1000() = benchmarkRule.measureRepeated {
        val dtos = buildFakeDtos(1000)
        runWithTimingDisabled { /* warmup/setup */ }
        UserMapper.mapList(dtos)
    }
}

DroidKaigi Day 2

Date: 2025/09/11

Composifying Your Not-Compose Code

Data structure

DroidKaigi Day 1

Date: 2025/09/11

Building with AI in Kotlin

Talks is presented by Jetbrains Dev Rels

AI Assisted Coding in Kotlin on the IntelliJ Ultimate

Although the AI demo is mostly from a Video, its demoing Interesting stuff:

Building AI

Composables beyond UI

Compose Concept

The Session begins with explaining how the Compose Work

Applying Compose to Audio Processing

Case Koruri Declarative Audio Processing Library Wave manipulation (pitch, volume) drawed as a block

Chain {
  SineWave()
  Volume()
}

Mix {
  SineWave()
  SineWave()
}

the interesting is, the library is complete the Compose capability to making a multimedia (Synthesizer), since now the wave manipulation can integrate seamlessly in the same approach in composable structure and state (UI state like touch or slide)

Gen AI for Developers

Tips when make Gen AI (Prompt Handling)

Android Librarian guide

Server Driven UI

Android Vitals Series

Date: 2025/08/24

Series of Article about Android Performance

Android AOP

Date: 2025/08/03

These days, an app isn’t just about building features — it also needs proper logging (performance, analytics). The problem is, teams often don’t have a clear agreement on how to do it, which leads to confusion when debugging and makes the business logic messy with logging code.

When i stumbled upon the AOP Concept it might the proper framework to help implementing the logs, lets see whether this one can help

to fix the java 11 requirement, need to install java 11 first, and add the line below on root gradle.properties then sync the project

org.gradle.java.home=/Library/Java/JavaVirtualMachines/temurin-11.jdk/Contents/Home

Android Makers: How to keep your app’s secrets, secret

Date: 2025/06/26

Interesting tools (approach)

  1. Secrets Gradle Plugin for Android using the same approach as the Google Maps SDK
  2. gitleaks a Static analytics tools
  3. git filter-branch manually check git history
  4. git-filter-repo remove logged secret changes by rewrite git history (using python)
  5. BFG Repo-cleaner remove logged secret changes by rewrite git history (using scala)
  6. hidden-secrets-gradle-plugin uses ndk with XOR (may be not maintained last commit are 2 years ago)
  7. bytemask mask secrets that make it difficult to reverse engineering
  8. Sekret store secrets on NDK using KMM plugin, also provide secure logging by using for annotated compatible string/char property
  9. Own API proxy servers

Jetpack Compose: Debugging recomposition

Date: 2025/05/25

Three Phase in Compose

  1. Composition: What UI to show, building tree of composables
  2. Layout: Where to Place UI, layout take those composables and works out where on the screen they will be shown
  3. Drawing: How it renders, Draw everything to screen

Compose can skip a phase entirely if nothing has changed in it

Prefer lambda modifiers when using frequently changing state, the video show case is using the scroll provider lambda over y property when performing translation, and reading the state inside the graphicsLayer

Android Api Level

Date: 2025/01/03

Since i often forget to about the name of the Version, the codename and the site is include the play store requirement changes, and major library info

How to Test Conflating Stateflow

Date: 2024/12/15

Separate assert and code triggering into 2 different set of coroutine launch

Please note that when using flow the code triggering should still use a separate launch and not inside the test block