Learning Jetpack Compose

Tutorial from: https://developer.android.com/jetpack/compose/tutorial

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Lesson 1: Composable functions

• @Composable annotation
• Define app’s UI programmatically
• Composable functions can only be called from other composable functions

Lesson 2: Layouts

• UI elements are organized in a hierarchy
• Can have nested elements
• Column - arranges elements vertically
• modifiers - used to configure/decorate composable

Lesson 3: Material Design

• With Compose, Material Design and its UI elements are provided out of the box.
• 3 Pillars of Material Design: Color, Typography, Shape
• Theme.kt - File where themes (i.e light, dark) are defined

Lesson 4: Lists and animations

• LazyRow, LazyColumn - composables that only render visible elements on screen, very efficient for long lists, avoids the complexity of RecyclerViews in XML layouts
• remember - stores local state in memory
• mutableStateOf - a single value holder whose reads and writes are observed by Compose
• Recomposition - Allows Composables to be redrawn automatically when observing state that changes

App Demo