Mobile App Performance Optimization

// ❌ Buruk: inflate baru setiap kali
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
    val view = LayoutInflater.from(parent.context)
        .inflate(R.layout.item_complex, parent, false)
    return ViewHolder(view)
}

// ✅ Baik: gunakan ListAdapter + DiffUtil
class ItemAdapter : ListAdapter<Item, ItemAdapter.ViewHolder>(DiffCallback()) {

    class DiffCallback : DiffUtil.ItemCallback<Item>() {
        override fun areItemsTheSame(old: Item, new: Item) = old.id == new.id
        override fun areContentsTheSame(old: Item, new: Item) = old == new
    }

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        holder.bind(getItem(position))
    }

    inner class ViewHolder(private val binding: ItemBinding) :
        RecyclerView.ViewHolder(binding.root) {
        fun bind(item: Item) {
            binding.title.text = item.title
            // ✅ Gunakan placeholder & cache untuk gambar
            Glide.with(binding.root)
                .load(item.imageUrl)
                .placeholder(R.drawable.placeholder)
                .override(200, 200)  // Resize!
                .diskCacheStrategy(DiskCacheStrategy.ALL)
                .into(binding.image)
        }
    }
}

// ❌ Buruk: rebuild semua widget
State build(BuildContext context) {
  return Column(
    children: items.map((item) => ItemWidget(item: item)).toList(),
  );
}

// ✅ Baik: gunakan ListView.builder (lazy build)
ListView.builder(
  itemCount: items.length,
  itemBuilder: (context, index) {
    return ItemWidget(item: items[index]);
  },
)

// ✅ Cache expensive computations
Widget build(BuildContext context) {
  return RepaintBoundary(
    child: CustomPaint(
      painter: ChartPainter(data: data),  // Hanya repaint jika data berubah
    ),
  );
}

// ✅ Gunakan const widgets
const Text('Hello')  // Tidak rebuild
Text('Hello')        // Bisa rebuild

val client = OkHttpClient.Builder()
    .cache(Cache(
        directory = File(context.cacheDir, "http_cache"),
        maxSize = 50L * 1024 * 1024  // 50 MB
    ))
    .addInterceptor { chain ->
        val request = if (isNetworkAvailable()) {
            chain.request().newBuilder()
                .cacheControl(CacheControl.FORCE_NETWORK)
                .build()
        } else {
            chain.request().newBuilder()
                .cacheControl(CacheControl.FORCE_CACHE)
                .build()
        }
        chain.proceed(request)
    }
    .addNetworkInterceptor { chain ->
        val response = chain.proceed(chain.request())
        response.newBuilder()
            .header("Cache-Control", "public, max-age=300")
            .build()
    }
    .connectTimeout(15, TimeUnit.SECONDS)
    .readTimeout(15, TimeUnit.SECONDS)
    .build()