Friday, October 11, 2024

What’s new within the Jetpack Compose January ’24 launch



Posted by Ben Trengrove, Android Developer Relations Engineer

Right now, as a part of the Compose January ‘24 Invoice of Supplies, we’re releasing model 1.6 of Jetpack Compose, Android’s fashionable, native UI toolkit that’s utilized by apps corresponding to Threads, Reddit, and Dropbox. This launch largely focuses on efficiency enhancements, as we proceed emigrate modifiers and enhance the effectivity of main components of our API.

To make use of in the present day’s launch, improve your Compose BOM model to 2024.01.00

implementation platform(‘androidx.compose:compose-bom:2024.01.00’)

Efficiency

Efficiency continues to be our high precedence, and this launch of Compose has main efficiency enhancements throughout the board. We’re seeing a further ~20% enchancment in scroll efficiency and ~12% enchancment to startup time in our benchmarks, and that is on high of the enhancements from the August ‘23 launch. As with that launch, most apps will see these advantages simply by upgrading to the newest model, with no different code modifications wanted.

The development to scroll efficiency and startup time comes from our continued deal with reminiscence allocations and lazy initialization, to make sure the framework is just doing work when it has to. These enhancements might be seen throughout all APIs in Compose, particularly in textual content, clickable, Lazy lists, and graphics APIs, together with vectors, and had been made potential partly by the Modifier.Node refactor work that has been ongoing for a number of releases.

There may be additionally new steerage so that you can create your personal customized modifiers with Modifier.Node.

Configuring the steadiness of exterior lessons

Compose compiler 1.5.5 introduces a brand new compiler possibility to supply a configuration file for what your app considers secure. This selection means that you can mark any class as secure, together with your personal modules, exterior library lessons, and normal library lessons, with out having to switch these modules or wrap them in a secure wrapper class. Word that the usual stability contract applies; that is simply one other handy methodology to let the Compose compiler know what your app ought to contemplate secure. For extra info on the best way to use stability configuration, see our documentation.

Generated code efficiency

The code generated by the Compose compiler plugin has additionally been improved. Small tweaks on this code can result in massive efficiency enhancements because of the truth the code is generated in each composable perform. The Compose compiler tracks Compose state objects to know which composables to recompose when there’s a change of worth; nonetheless, many state values are solely learn as soon as, and a few state values are by no means learn in any respect however nonetheless change incessantly! This replace permits the compiler to skip the monitoring when it isn’t wanted.

Compose compiler 1.5.6 additionally allows “intrinsic keep in mind” by default. This mode transforms keep in mind at compile time to take note of info we have already got about any parameters of a composable which can be used as a key to keep in mind. This hastens the calculation of figuring out if a remembered expression wants reevaluating, but additionally means should you place a breakpoint contained in the keep in mind perform throughout debugging, it might now not be referred to as, because the compiler has eliminated the utilization of keep in mind and changed it with totally different code.

Composables not being skipped

We’re additionally investing in making the code you write extra performant, robotically. We wish to optimize for the code you intuitively write, eradicating the necessity to dive deep into Compose internals to grasp why your composable is recomposing when it shouldn’t.

This launch of Compose provides help for an experimental mode we’re calling “sturdy skipping mode”. Robust skipping mode relaxes a number of the guidelines about which modifications can skip recomposition, shifting the steadiness in direction of what builders count on. With sturdy skipping mode enabled, composables with unstable parameters may also skip recomposition if the identical cases of objects are handed in to its parameters. Moreover, sturdy skipping mode robotically remembers lambdas in composition that seize unstable values, along with the present default habits of remembering lambdas with solely secure captures. Robust skipping mode is presently experimental and disabled by default as we don’t contemplate it prepared for manufacturing utilization but. We’re evaluating its results earlier than aiming to show it on by default in Compose 1.7. See our steerage to experiment with sturdy skipping mode and assist us discover any points.

Textual content

Adjustments to default font padding

This launch now makes the includeFontPadding setting false by default. includeFontPadding is a legacy property that provides additional padding based mostly on font metrics on the high of the primary line and backside of the final line of a textual content. Making this setting default to false brings the default textual content structure extra according to widespread design instruments, making it simpler to match the design specs generated. Upon upgrading to the January ‘24 launch, you may even see small modifications in your textual content structure and screenshot checks. For extra details about this setting, see the Fixing Font Padding in Compose Textual content weblog put up and the developer documentation.

Line height with includeFontPadding as false on the left and true on the right.

Help for nonlinear font scaling

The January ‘24 launch makes use of nonlinear font scaling for higher textual content readability and accessibility. Nonlinear font scaling prevents massive textual content parts on display screen from scaling too massive by making use of a nonlinear scaling curve. This scaling technique signifies that massive textual content does not scale on the identical charge as smaller textual content.

Drag and drop

Compose Basis provides help for platform-level drag and drop, which permits for content material to be dragged between apps on a tool operating in multi-window mode. The API is 100% suitable with the View APIs, which implies a drag and drop began from a View might be dragged into Compose and vice versa. To make use of this API, see the code pattern.

Moving image illustrating drag and drop feature

Extra options

Different options landed on this launch embrace:

    • Help for LookaheadScope in Lazy lists.
    • Fastened composables which were deactivated however saved alive for reuse in a Lazy checklist not being filtered by default from semantics bushes.
    • Spline-based keyframes in animations.
    • Added help for choice by mouse, together with textual content.

Get began!

We’re grateful for all the bug stories and have requests submitted to our problem tracker — they assist us to enhance Compose and construct the APIs you want. Proceed offering your suggestions, and assist us make Compose higher!

Questioning what’s subsequent? Take a look at our roadmap to see the options we’re presently fascinated about and dealing on. We are able to’t wait to see what you construct subsequent!

Joyful composing!



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