jetc.dev Newsletter Issue #100
It’s the 💯 issue! 🎉
In it, we look at the first alpha for Compose
1.2.0. We look at button presses
and flow operators, plus writing composable libraries and testing via robots. We
take another glance at Glance, and we see what you think of Material You.
Reviewing the release notes for the latest Jetpack Compose update!
1.1.0 is not yet stable, but we already have a
1.2.0-alpha01 release. This is
how things went the last time around, where the 1.1.0 first alpha came out
before 1.0.0 shipped a stable release.
This alpha does not have too much. Of note:
userScrollEnabledas a parameter to the
Lazy...family of composables (e.g.,
LazyColumn()). If this is
false, users cannot scroll via gestures, though programmatic scrolling is still possible
They added an
onSizeChangedfunction type parameter to
ModalBottomSheetState, to bypass the half-expanded state when collapsing a bottom sheet
Also, ConstraintLayout for Compose shipped a
One Off the Stack, One Off the Slack
You’ve got questions. That’s understandable!
Button() has an
onClick parameter to detect clicks, where the button is pressed
and released. For more complex interactions, such as detecting a press independent
of a click, you need to work with
InteractionSource, as we see in this week’s
highlighted Stack Overflow question.
If you try using a
Flow operator, such as
map(), in a composable where you eventually
collectAsState() on the
Flow, you get a
Flow operator functions should not be invoked within composition Lint error. Learn
why that error shows up, and what to do about it, in this week’s highlighted
#compose Slack thread!
Posts, videos, and other new information related to Jetpack Compose!
William Barbosa of PSPDFKit walks us through API design, with an eye towards libraries for Compose UI. Creating a solid API is not merely a matter of just exposing composables — it requires thinking through how developers will consume that API and how you can simplify their lives. Those lessons hold true regardless of whether your composables will be used by the world or just by some team members.
Fernando Prieto is exploring UI testing for Compose-based projects. His
looked at OkHttp’s
MockWebServer for mocking HTTPS responses. This post
looks at the robot pattern: creating an API for manipulating your UI under
test, to make tests easier to write and more expressive.
William Shelor delivered an Android Worldwide presentation looking at the speed of our composables and what we can do to improve upon it. Beyond looking at the impacts of tooling on our day-to-day apparent performance, William explores how the complexity of our composables impacts speed, using memoization to reduce computation within composables, and other steps to avoid recomposition.
Damien Petla offers up several approaches for implementing a design system,
from simple extension functions for
MaterialTheme, all the way through
MaterialTheme and rolling a true custom theme.
Enes Zor walks us through creating an app widget using Glance, the Jetpack composable framework for app widgets and Wear OS tiles. You might also be interested in Igor Escodro’s introduction to Glance as well.
Jaewoong Eum gives us a quick tour of the Material You aspects of the Compose
Material3 library. The feature most commonly associated with Material You is
the dynamic color palette based on the user’s current wallpaper. If you are interested
in Material3, you may also be interested in Hugo Visser’s gist
showing how to use Material3 and “classic” editions of
MaterialTheme() at the same time.
Other Interesting Links
- RichText Editor in Jetpack Compose
- Adding AlertDialog with Jetpack Compose to Android apps
- Jetpack Compose Basics - How to use and create own CompositionLocal
- Medium: How Kotlin By Variable Delegate Helps Me Avoid Anti-Pattern
- Medium: Carousel Slider in Android Jetpack Compose with Auto Play
- Remember, Remember, Jetpack Compose
- Medium: Jetpack Compose Migration: Part 1. Get Started
100% pure code!
Sebas LG created a library that offers
rememberScoped(), a form of
that lives a bit longer, including across configuration changes, for finer-grained
scope control that you get with the Jetpack
ViewModel and Navigation for Compose.
Anton Shilov brings us a small
ConfirmationButton() composable. This renders
like a button with a small thumb image on top of it, which the user needs to slide
across the button face to perform an action.
The Varabyte team created Kobweb, a extensive Web app framework built on top of Compose for Web. It offers integrated routing, shared content between client and server, Markdown formatting, and a rich set of widgets.
Other Interesting Links
- GitHub: Anmol92verma / JetCalendarView
- GitHub: roudikk / compose-navigator
- GitHub: funyin / FormValidator
…And One More Thing
I’m going to be writing a bit about Compose for Wear, the Jetpack composable library for Wear OS apps. Most of that will be over in the CommonsBlog, as the material is going to be a bit long and code-heavy for this space.
This week, I start off by looking at using
for showing content on the screen edges, supporting following the curvature of
- 2022-01-11: Screenshot testing! Accessibility! Text and fields! Rendering composables to bitmaps! Tooltips! And... Wordle in the terminal?!?
- 2022-01-04: rememberSaveable()! White-label apps via product flavors! Loading buttons! Sliders! Canvas! Action menus! Preferences! And... ugly gradients?!?
- 2021-12-28: Glance! Space! Compose Multiplatform in the real world! Formatted text in fields! State management! Date pickers! Chat UIs! And, how did 2021 turn out?