Apa itu Jetpack Compose?

Question

Accepted Answer

**Jetpack Compose** yaiku **toolkit UI deklaratif** modern Android — nggawe UI kanthi fungsi Kotlin composable tinimbang layout XML. Iku cara sing direkomendasake Google kanggo Android UI anyar, menawarake cara sing reaktif, ringkas, lan luwih produktif kanggo nggawe antarmuka.

## Apa Compose

```text
JETPACK COMPOSE = a declarative UI toolkit (Kotlin code, no XML):
  → describe the UI as COMPOSABLE FUNCTIONS (annotated @Composable)
  → DECLARATIVE + REACTIVE — describe UI for a given state; it updates when state changes
  → Google's RECOMMENDED modern approach (similar philosophy to Flutter, React, SwiftUI)
```

## Fungsi composable

```kotlin
@Composable
fun Greeting(name: String) {
  Column {                            // layout composable
    Text("Hello, $name")              // text composable
    Button(onClick = { /* ... */ }) {
      Text("Click me")
    }
  }
}
// → compose UI by CALLING composable functions (composition); no XML, no findViewById
```

## State lan rekomposisi

```kotlin
@Composable
fun Counter() {
  var count by remember { mutableStateOf(0) }   // STATE
  Button(onClick = { count++ }) {                // change state
    Text("Count: $count")                         // UI reads state
  }
  // → when state changes, Compose RECOMPOSES (re-runs affected composables) → UI updates
}
```

Perubahan state magatake **rekomposisi** (Compose njalanake maneh fungsi composable sing kena pangaruhe kanggo nganyarke UI) — model reaktif.

## Compose versus sistem View tradisional

```text
TRADITIONAL → XML layouts + imperative view manipulation (findViewById, setText, etc.)
COMPOSE → declarative Kotlin; less boilerplate; reactive state; more productive;
  the modern, recommended direction (new apps; interop with existing Views possible)
```

## Mengapa iku penting

Pamahaman babagan Jetpack Compose penting amarga iku **cara modern sing direkomendasake Google kanggo Android UI** lan arah saka pengembangan Android UI, dadi pengetahuan sing saya-saya penting.

Compose yaiku **toolkit UI deklaratif** sing nggawe UI kanthi fungsi Kotlin composable tinimbang layout XML — nandisake perubahan mendasar babagan cara Android UI dibangun, selaras karo filosofi deklaratif modern sing bareng karo Flutter, React, lan SwiftUI.

Pamahaman babagan **model deklaratif, reaktif** — nggambarake UI minangka fungsi composable kanggo state tartamtu, kanthi UI sing niyat nganyarke (liwat **rekomposisi**) nalika state owah — yaiku konsep inti, beda karo cara imperatif tradisional (manipulasi view kanthi cara manual karo findViewById lan setter).

Pamahaman babagan **composables** (nggawe UI kanthi nggabung fungsi, tanpa XML utawa findViewById) lan **state karo rekomposisi** (owah-owahan state magatake njalanake maneh composables sing kena pangaruhe kanggo nganyarke UI) kudu ana kanggo nggawe UI Compose.

Pamahaman babagan **kontras karo sistem View tradisional** (XML + manipulasi imperatif versus deklaratif Kotlin karo boilerplate sing luwih sithik, state reaktif, lan produktivitas sing luwih dhuwur) ngandharake mengapa Compose luwih dipilih lan carane prabeda.

Amarga Compose yaiku cara sing direkomendasake Google kanggo Android UI anyar (kanthi app anyar sing saya-saya nggunakake lan iku arah sing jelas saka pengembangan Android UI), lan amarga pamahaman babagan model deklaratif, reaktife lan carane prabeda karo sistem tradisional yaiku saya-saya penting kanggo kerja Android modern, pamahaman Android sing penting, saya-saya penting — cara modern, sing direkomendasake kanggo nggawe Android UI, nandisake arah platform lan pengetahuan sing saya-saya dikarepake kanggo pengembang Android sing nggawe app anyar, evolusi signifikan saka sistem view berbasis XML tradisional.