JetPack Compose

Juan Gabriel Gutierrez R.

Agenda

• Problems With Android UI Development
• What's Jetpack Compose?
• Declarative vs Imperative Way
• Composable Functions
• Data Flow
• Q&A

Problems With Android UI Development

• Fixes for Android UI libraries issues depends on new releases of OS versions.
• There are multiple design problems in the legacy code.

What's JetPack Compose?

A declarative toolkit for building UI

that combines a reactive programming model with the conciseness and ease of use of the Kotlin programming language.

ANDROID X

Declarative vs Imperative Way

Declarative programming is “the act of programming in languages that conform to the mental model of the developer rather than the operational model of the machine.”

In computer science, declarative programming is a programming paradigm that expresses the logic of a computation without describing its control flow.

I draw the line between declarative and non-declarative at whether you can trace the code as it runs. Regex is 100% declarative, as it’s untraceable while the pattern is being executed.

Declarative vs Imperative Way

How

What

Declarative vs Imperative Way

Composable Functions

Kotlin

Pure Functions?

UI as a Function

Composable Functions

Data Flow

Events

Data

Screen

Gallery

Profile

Profile

Recap

• Fully compatible with your existing app/code
• It’s in active development  and not ready for production yet
• Making things simpler is a big focus with Jetpack Compose
• Kotlin is really important to get an efficient declarative way of UI building.

Q&A