Tag Archives: Flutter

Flutter: a Portable UI Framework for Mobile, Web, Embedded, and Desktop

Posted by the Flutter Team

Today marks an important milestone for the Flutter framework, as we expand our focus from mobile to incorporate a broader set of devices and form factors. At I/O, we’re releasing our first technical preview of Flutter for web, announcing that Flutter is powering Google’s smart display platform including the Google Home Hub, and delivering our first steps towards supporting desktop-class apps with Chrome OS.

From Mobile to Multi-Platform

For a long time, the Flutter team mission has been to build the best framework for developing mobile apps for iOS and Android. We believe that mobile development is ripe for improvement, with developers today forced to choose between building the same app twice for two platforms, or making compromises to use cross-platform frameworks. Flutter hits the sweet spot of enabling a single codebase to deliver beautiful, fast, tailored experiences with high developer productivity for both platforms, and we’ve been excited to see how our early efforts have flourished into one of the most popular open source projects.

As we started to home in on our 1.0 release last year, we began experimenting with broadening the scope of Flutter to other platforms. This was triggered both by internal teams within Google who are increasingly relying on Flutter, as well as the latent potential of the Dart platform for delivering portable experiences. In particular, a small team who were already building a web framework for Dart for internal usage started an exploratory project (codename “Hummingbird”) to evaluate the technical merits of porting the Flutter engine to support the standards-based web.

The results of this project were startling, thanks in large part to the rapid progress in web browsers like Chrome, Firefox, and Safari, which have pervasively delivered hardware-accelerated graphics, animation, and text as well as fast JavaScript execution. Within a few months of beginning the project, we had the core Flutter framework primitives working, and soon after we had demos running on mobile and desktop browsers. Along with Dart’s long pedigree of compiling for the web, this proved that we could also bring the Flutter framework and apps to run on the web.

In parallel, the core Flutter project has been making progress to enable desktop-class apps, with input paradigms such as keyboard and mouse, window resizing, and tooling for Chrome OS app development. The exploratory work that we did for embedding Flutter into desktop-class apps running on Windows, Mac and Linux has also graduated into the core Flutter engine.

A Portable UI Framework for All Screens

Flutter Mobile, Web, Desktop, and Embedded

It’s worth pausing for a moment to acknowledge the business potential of a high-performance, portable UI framework that can deliver beautiful, tailored experiences to such a broad variety of form factors from a single codebase.

For startups, the ability to reach users on mobile, web, or desktop through the same app lets them reach their full audience from day one, rather than having limits due to technical considerations. Especially for larger organizations, the ability to deliver the same experience to all users with one codebase reduces complexity and development cost, and lets them focus on improving the quality of that experience.

With support for mobile, desktop, and web apps, our mission expands: we want to build the best framework for developing beautiful experiences for any screen.

Flutter for Web

This week, we are releasing the first technical preview of Flutter for the web. While this technology is still in development, we are ready for early adopters to try it out and give us feedback. Our initial vision for Flutter on the web is not as a general purpose replacement for the document experiences that HTML is optimized for; instead we intend it as a great way to build highly interactive, graphically rich content, where the benefits of a sophisticated UI framework are keenly felt.

To showcase Flutter for the web, we worked with the New York Times to build a demo. In addition to world-class news coverage, the New York Times is famous for its crossword and other puzzle games. Since avid puzzlers want to play on whatever device they’re using at the time, their development team was attracted to Flutter as a potential solution for their needs. Discovering that they could reach the web with the same code was a huge boon. At Google I/O this week, you can get a sneak peek of their newly refreshed KENKEN puzzle game, which runs with the same code on Android, iOS, web, Mac, and Chrome OS.

ken-gratulations puzzle

Here’s what Eric von Coelln, Executive Director of Puzzles at the New York Times has to say about their experiences with Flutter:

"The New York Times Crossword has more than 400,000 stand-alone subscriptions and is a daily ritual for puzzle solvers. Along with the Crossword, we’ve grown our portfolio of digital puzzles that reaches more than two million solvers each month.

We were already beginning to explore Flutter as a potential solution to the challenge of quickly developing engaging, high-quality mobile experiences. Now the addition of being able to publish to web makes Flutter an even more appealing option to quickly deploy across all of our user platforms. This update of our old Flash-based KenKen game into a multi-platform playable experience is something we’re excited to bring to our solvers this year.”

There’s lots more to say about Flutter for web than we have space for here, so check out the dedicated article about Flutter for web on the Flutter blog.

At this early stage, we’re eager to get your feedback on how you’d like to use Flutter for web. We expect to rapidly evolve the code, with a particular focus on performance, and harmonizing the codebase with the rest of the Flutter project.

Flutter for Mobile Devices

The core Flutter framework also receives an upgrade this week, with the immediate availability of Flutter 1.5 in our stable channel. Flutter 1.5 includes hundreds of changes in response to developer feedback, including updates for new App Store iOS SDK requirements, updates to the iOS and Material widgets, engine support for new device types, and Dart 2.3 featuring new UI-as-code language features.

As the framework itself matures, we’re investing in building out the supporting ecosystem. The architectural model of Flutter has always prioritized a small core framework, supplemented by a rich package community. In the last few months, Google has contributed production-quality packages for web views, Google Maps, and Firebase ML Vision, and this week, we’re adding initial support for in-app payments. And with over 2,000 open source packages available for Flutter, there are options available for most scenarios.

One particularly exciting project that we’re announcing this week at I/O is the ML Kit Custom Image Classifier. Built using Flutter and Firebase, it offers an easy-to-use app-based workflow for creating custom image classification models. You can collect training data using the phone's camera, invite others to contribute to your datasets, trigger model training, and use trained models, all from the same app.

Flutter ML Kit: create datasets, collaborate to collect data, train model, run inference

Flutter continues to grow in popularity and adoption. A growing roster of demanding customers including eBay, Sonos, Square, Capital One, Alibaba and Tencent are developing apps with Flutter. And they’re having fun! Here’s what Larry McKenzie, a senior developer at eBay had to say about Flutter:

“Flutter is fast! Features that once took us multiple days to implement can be finished in a single day. Many problems we used to spend a lot of time on, simply no longer occur. Our team can now focus on creating more polished user experiences and delivering functionality. Flutter is enabling us to exceed expectations!”

More broadly, LinkedIn recently conducted a study that showed Flutter is the single fastest-growing skill among software engineers, based on site members claiming it on their profile over the last 12 months. And in the recent 2019 StackOverflow developer survey, Flutter was listed as one of the most-loved developer frameworks.

Flutter for Desktop

Flutter is also being used on the desktop. For some months, we’ve been working on the desktop as an experimental project. But now we’re graduating this into Flutter engine, integrating this work directly into the mainline repo. While these targets are not production-ready yet, we have published early instructions for developing Flutter apps to run on Mac, Windows, and Linux.

Another quickly growing Flutter platform is Chrome OS, with millions of Chromebooks being sold every year, particularly in education. Chrome OS is a perfect environment for Flutter, both for running Flutter apps, and as a developer platform, since it supports execution of both Android and Linux apps. With Chrome OS, you can use Visual Studio Code or Android Studio to develop a Flutter app that you can test and run locally on the same device without an emulator. You can also publish Flutter apps for Chrome OS to the Play Store, where millions of others can benefit from your creation.

Flutter for Embedded Devices

As the final example of Flutter’s portability, we offer Flutter embedded on other devices. We recently published samples that demonstrate Flutter running directly on smaller-scale devices like Raspberry Pi, and we offer an embedding API for Flutter that allows it to be used in scenarios including home, automotive and beyond.

Perhaps one of the most pervasive embedded platforms where Flutter is already running is on the smart display operating system that powers the likes of Google Home Hub.

Within Google, some Google-built features for the Smart Display platform are powered by Flutter today. And the Assistant team is excited to continue to expand the portfolio of features built with Flutter for the Smart Display in the coming months; the goal this year is to use Flutter to drive the overall system UI.

Other Resources

We often get asked by developers how they can get started with Flutter. We are pleased today to announce a comprehensive new training course for Flutter, built by The App Brewery, authors of the highest-rated iOS training course on Udemy. Their new course has over thirty hours of content for Flutter, including videos, demos and labs, and with Google’s sponsorship, they are announcing today a time-limited discount of this course from the retail price of $199 to just $10.

Many developers are creating inspiring apps with Flutter. In the run-up to Google I/O, we ran a contest called Flutter Create to encourage developers to see what they could build with Flutter in 5KB or less of Dart code. We had over 750 unique entries from around the world, with some amazing examples that pushed what we imagine would be possible in such a small size.

Today, we’re announcing the winners, which can be found on flutter.dev/create. Congratulations to the overall winner, Zebiao Hu, who wins a fully-loaded iMac Pro worth over $10,000!

Flutter is no longer a mobile framework, but a multi-platform framework that can help you reach your users wherever they are. We can’t wait to see what you’ll build with Flutter on the web, desktop, mobile, and beyond!

Launching Flutter 1.2 at Mobile World Congress

Posted by the Flutter team

The Flutter team is coming to you live this week from Mobile World Congress in Barcelona, the largest annual gathering of the mobile technology industry. One year ago, we announced the first beta of Flutter at this same event, and since then Flutter has grown faster than we could have imagined. So it seems fitting that we celebrate this anniversary occasion with our first stable update release for Flutter.

Flutter 1.2

Flutter 1.2 is the first feature update for Flutter. We've focused this release on a few major areas:

  • Improved stability, performance and quality of the core framework.
  • Work to polish visual finish and functionality of existing widgets.
  • New web-based tooling for developers building Flutter applications.

Having shipped Flutter 1.0, we focused a good deal of energy in the last couple of months on improving our testing and code infrastructure, clearing a backlog of pull requests, and improving performance and quality of the overall framework. We have a comprehensive list of these requests in the Flutter wiki for those who are interested in the specifics. This work also included broader support for new UI languages such as Swahili.

We continue to make improvements to both the Material and Cupertino widget sets, to support more flexible usage of Material and continue to strive towards pixel-perfect fidelity on iOS. The latter work includes support for floating cursor text editing, as well as showing continued attention to minor details (for example, we updated the way the text editing cursor paints on iOS for a faithful representation of the animation and painting order). We added support for a broader set of animation easing functions, inspired by the work of Robert Penner. And we added support for new keyboard events and mouse hover support, in preparation for deeper support for desktop-class operating systems.

The plug-in team has also been busy in Flutter 1.2, with work well underway to support in-app purchases, as well as many bug fixes for video player, webview, and maps. And thanks to a pull request contributed by a developer from Intuit, we now have support for Android App Bundles, a new packaging format that helps in reducing app size and enables new features like dynamic delivery for Android apps.

Lastly, Flutter 1.2 includes the Dart 2.2 SDK, an update that brings significant performance improvements to compiled code along with new language support for initializing sets. For more information on this work, you can read the Dart 2.2 announcement.

(As an aside, some might wonder why this release is numbered 1.2. Our goal is to ship a 1.x release to the 'beta' channel on about a monthly basis, and to release an update approximately every quarter to the 'stable' channel that is ready for production usage. Our 1.1 last month was a beta release, and so 1.2 is therefore our first stable release.)

New Tools for Flutter Developers

Mobile developers come from a variety of backgrounds and often prefer different programming tools and editors. Flutter itself supports different tools, including first-class support for Android Studio and Visual Studio Code as well as support for building apps from the command line, so we knew we needed flexibility in how we expose debugging and runtime inspection tools.

Alongside Flutter 1.2, we're delighted to preview a new web-based suite of programming tools to help Flutter developers debug and analyze their apps. These tools are now available for installation alongside the extensions and add-ins for Visual Studio Code and Android Studio, and offer a number of capabilities:

  • A widget inspector, which enables visualization and exploration of the tree hierarchy that Flutter uses for rendering.
  • A timeline view that helps you diagnose your application at a frame-by-frame level, identifying rendering and computational work that may cause animation 'jank' in your apps.
  • A full source-level debugger that lets you step through code, set breakpoints and investigate the call stack.
  • A logging view that shows activity you log from your application as well as network, framework and garbage collection events.

We plan to invest further in this new web-based tooling for both Flutter and Dart developers and, as integration for web-based experiences improves, we plan to build these services directly into tools like Visual Studio Code.

What's next for Flutter?

In addition to the engineering work, we took some time after Flutter 1.0 to document our 2019 roadmap, and you'll see that we've got plenty of work ahead of us.

A big focus for 2019 is growing Flutter beyond mobile platforms. At Flutter Live, we announced a project codenamed "Hummingbird", which brings Flutter to the web, and we plan to share a technical preview in the coming months. In addition, we continue to work on bringing Flutter to desktop-class devices; this requires work both at the framework level as described above, as well as the ability to package and deploy applications for operating systems like Windows and Mac, in which we're investing through our Flutter Desktop Embedding project.

Flutter Create: what can you do with 5K of Dart?

This week, we're also excited to launch Flutter Create, a contest that challenges you to build something interesting, inspiring, and beautiful with Flutter using five kilobytes or less of Dart code. 5K isn't a lot -- for a typical MP3 file, it's about a third of a second of music -- but we're betting you can amaze us with what you can achieve in Flutter with such a small amount of code.

The contest runs until April 7th, so you've got a few weeks to build something cool. We have some great prizes, including a fully-loaded iMac Pro developer workstation with a 14-core processor and 128GB of memory that is worth over $10,000! We'll be announcing the winners at Google I/O, where we'll have a number of Flutter talks, codelabs and activities.

In closing

Flutter is now one of the top 20 software repos on Github, and the worldwide community grows with every passing month. Between meetups in Chennai, India, articles from Port Harcourt, Nigeria, apps from Copenhagen, Denmark and incubation studios in New York City, USA, it's clear that Flutter continues to become a worldwide phenomenon, thanks to you. You can see Flutter in apps that have hundreds of millions of users, and in apps from entrepreneurs who are bringing their first idea to market. It's exciting to see the range of ideas you have, and we hope that we can help you express them with Flutter.

Attendees of a Flutter deep dive at Technozzare, SRM University.

Finally, we've recently launched a YouTube channel exclusively dedicated to Flutter. Be sure to subscribe at flutter.dev/youtube for shows including the Boring Flutter Development Show, Widget of the Week, and Flutter in Focus. You'll also find a new case study from Dream11, a popular Indian fantasy sports site, as well as other Developer Stories. See you there!

Flutter 1.0: Google’s Portable UI Toolkit

Posted by Tim Sneath, Group Product Manager for Flutter

Today, at Flutter Live, we're announcing Flutter 1.0, the first stable release of Google's UI toolkit for creating beautiful, native experiences for iOS and Android from a single codebase.

Cross-platform mobile development today is full of compromise. Developers are forced to choose between either building the same app multiple times for multiple operating systems, or to accept a lowest common denominator solution that trades native speed and accuracy for portability. With Flutter, we believe we have a solution that gives you the best of both worlds: hardware-accelerated graphics and UI, powered by native ARM code, targeting both popular mobile operating systems.

Introducing Flutter

Flutter doesn't replace the traditional Apple and Android app models for building mobile apps; instead, it's an app engine that you can either embed into an existing app or use for an entirely new app.

We think of the characteristics of Flutter along four dimensions:

  1. Flutter enables you to build beautiful apps. We want to enable designers to deliver their full creative vision without being forced to water it down due to limitations of the underlying framework. Flutter lets you control every pixel on the screen, and its powerful compositing capabilities let you overlay and animate graphics, video, text and controls without limitation. Flutter includes a full set of widgets that deliver pixel-perfect experiences on both iOS and Android. And it enables the ultimate realization of Material Design, Google's open design system for digital experiences.
  2. Flutter is fast. It's powered by the same hardware-accelerated Skia 2D graphics engine that underpins Chrome and Android. We architected Flutter to be able to support glitch-free, jank-free graphics at the native speed of your device. Flutter code is powered by the world-class Dart platform, which enables compilation to native 32-bit and 64-bit ARM code for iOS and Android.
  3. Flutter is productive. Flutter introduces stateful hot reload, a revolutionary new capability for mobile developers and designers to iterate on their apps in real time. With stateful hot reload, you can make changes to the code of your app and see the results instantly without restarting your app or losing its state. Stateful hot reload transforms the way developers build an app -- and in user surveys, developers say it makes their development cycle three times more productive.
  4. Lastly, Flutter is open. Flutter is an open source project with a BSD-style license, and includes the contributions of hundreds of developers from around the world. In addition, there's a vibrant ecosystem of thousands of plug-ins. And because every Flutter app is a native app that uses the standard Android and iOS build tools, you can access everything from the underlying operating system, including code and UI written in Kotlin or Java on Android, and Swift or Objective-C on iOS.

Put this all together, combine it with best-in-class tooling for Visual Studio Code, Android Studio, IntelliJ or the programmer's editor of your choice, and you have Flutter -- a development environment for building beautiful native experiences for iOS or Android from a single codebase.

Flutter Growth and Momentum

We announced the first beta of Flutter at Mobile World Congress ten months ago, and we've been excited to see how quickly it has been adopted by the broader community, as evidenced by the thousands of Flutter apps that are already published to the Apple and Google Play stores even before our 1.0 release. It's clear that developers are ready for a new approach to UI development.

Internally, Flutter is being used at Google for a wide array of products, with Google Ads already having switched to Flutter for their iOS and Android app. And even before 1.0, a wide range of global customers including Abbey Road Studios, Alibaba, Capital One, Groupon, Hamilton, JD.com, Philips Hue, Reflectly, and Tencent are developing or shipping apps with Flutter.

Michael Jones, Senior Director of Engineering from the Capital One team, says the following about their experiences with Flutter:

"We are excited by Flutter's unique take on high-performing cross-platform development. Our engineers have appreciated the rapid development promise and hot reload capabilities, and over the past year we have seen tremendous progress in the framework and especially the native integration story.

"Flutter can allow Capital One to think of features not in an 'iOS or Android-first' fashion, but rather in a true mobile-first model. We are excited to see Flutter 1.0 and continue to be impressed with the pace of advancement and the excitement in the engineering community."

At the Flutter Live event today, the popular payment service Square announced two new Flutter SDKs that make it easy to accept payments for goods and services with Flutter, whether in-person using a Square payment reader or by taking payments inside a mobile app. Square demonstrated an example of using their payments SDK using an app from Collins Family Orchards, a family farm that grows and sells fruit in farmers markets around the Pacific Northwest.

The developer of the Collins Family Orchards app, Dean Papastrat, had this to say about his experience:

"I was blown away by the speed of all the animations and transitions in production builds. As a web developer, it was super easy to make the transition to Flutter, and I can't believe I was able to build a fully working app that can take payments in just a week."

Also at Flutter Live, 2Dimensions announced the immediate availability of Flare, a remarkable new tool for designers to create vector animations that can be embedded directly into a Flutter app and manipulated with code. Flare eliminates the need to design in one app, animate in another, then convert all of that to device-specific assets and code.

Animations built with Flare can be embedded into an existing Flutter app as a widget, allowing them to participate in the full compositor and be overlaid with other text, graphical layers or even UI widgets. Integrating in this way frees animations from the 'black box' limitations of other architectures, and allows ongoing collaboration between designers and developers right up to the completion of the app. Such tight integration between Flutter and Flare provides a uniquely compelling offering for digital designers and animators who want to create highly-polished mobile experiences.

Another partner who has bet on Flutter is Nevercode, a fast-growing provider of continuous integration and delivery (CI/CD) tooling for mobile apps. At Flutter Live, they announced Codemagic, a new tool designed specifically for Flutter to make it easy to automate the process of building and packaging Flutter apps for both Android and iOS from a single automation. Available today in beta, Codemagic allows you to select a GitHub repo containing a Flutter project, and with just a few clicks, create continuous build flows that run tests, and generate binary app bundles that you can upload to the Apple and Google Play stores.

We put together a short video to highlight the range and variety of the apps developers have been building with Flutter since the beta:

New Features in Flutter 1.0

Since the first beta, we've been working to add features and polish to Flutter. In particular, we rounded out our support for pixel-perfect iOS apps with new widgets; added support for nearly twenty different Firebase services; and worked on improving performance and reducing the size of Flutter apps. We've also closed out thousands of issues based on feedback from the community.

Flutter also includes the latest version of the Dart platform, 2.1, an update to Dart 2 that offers smaller code size, faster type checks, and better usability for type errors. Dart 2.1 also has new language features to improve productivity when building user experiences. Developers who have already adopted Dart 2.1 tell us they're seeing significant speed improvements just by switching to the latest engine:

While the primary focus of the 1.0 release is bug fixes and stabilization, we're also introducing previews of two major new features for developers to try out in preview mode that we anticipate will ship in our next quarterly release in February 2019: Add to App and platform views.

Add to App

When we first built Flutter, we focused on productivity for the scenario where someone is building a new application from scratch. But of course, not everyone has the luxury of being able to start with a clean slate. Talking to some of our larger customers, it was clear that they wanted to use Flutter for new user journeys or features within an existing application, or to convert their existing application to Flutter in stages.

The architecture of Flutter supports this model well: after all, every Flutter app includes a host Android and iOS container. But we've been working to make it easier to incrementally adopt Flutter by updating our templates, tooling and guidance for existing apps. We've made it easier to share assets between Flutter and host code. And we've also reworked the tooling to make it easy to attach to an existing Flutter process without launching the debugger with the application.

We will continue to work to make this experience even better. Even though a number of customers are already using our guidance on Add to App successfully, we're continuing to add samples and expand support for complex scenarios. In the meantime, our instructions for adding Flutter to existing apps are on our wiki, and you can track the remaining work on the GitHub project board.

Platform Views

While Add To App is useful as a way to gradually introduce Flutter to an existing application, sometimes it's useful to go the other way round and embed an Android or iPhone platform control in a Flutter app.

So we've introduced platform view widgets (AndroidView and UiKitView) that let you embed this kind of content on each platform. We've been previewing Android support for a couple of months, but now we're expanding support to iOS, and starting to add plug-ins like Google Maps and WebView that take advantage of this.

Like other components, our platform view widgets participate in the composition model, which means that you can integrate it with other Flutter content. For example, in the screenshot above, the floating action button in the bottom right corner is a Flutter widget that has background color with 50% alpha. This demonstrates the unique architectural advantages of Flutter well.

While this work is ready for developers to try out, we're continuing to work on improving performance and device compatibility, so we recommend caution if deploying apps that depend on PlatformViews. We're continuing to actively optimize platform views and expect them to be ready for production in time for our next quarterly update.

Flutter Beyond Mobile

The primary target for Flutter has so far been iOS and Android. Yet our ambitions for Flutter extend beyond mobile to a broader set of platforms. Indeed, from the outset Flutter was architected as a portable UI toolkit that is flexible enough to go wherever pixels are painted.

Some of this work has already been taking place in the open. Flutter Desktop Embedding is an early-stage project that brings Flutter to desktop operating systems including Windows, MacOS, and Linux. We also recently published informal details of using Flutter on Raspberry Pi, as a way to demonstrate Flutter embedding support to smaller-scale devices that may not include a full desktop environment.

This week, at Flutter Live, we gave the first sneak peek of an experimental project we're working on in the labs that significantly expands where Flutter can run.

Hummingbird is a web-based implementation of the Flutter runtime that takes advantage of the capability of the Dart platform to compile not just to native ARM code but also to JavaScript. This enables Flutter code to run on the standards-based web without change.

We have a separate blog article on Medium that describes the technical implementation details of Hummingbird. And we'll have a lot more to share on Hummingbird at Google I/O in 2019: hope to see you there!

Of course, mobile remains our immediate priority, and you can expect to see the bulk of our investment in these core mobile scenarios over the coming months.

Conclusion

With the release of Flutter 1.0, we've established a new 'stable' channel, in addition to the existing beta, dev, and master channels. The stable channel updates less often than other channels, but we have a higher confidence in its quality since builds have already been vetted through the other channels. We anticipate that we'll update our stable channel on a quarterly basis with our most battle-tested builds.

You can download Flutter 1.0 from our website at https://flutter.io, where you can also find documentation for developers transitioning from other frameworks, code labs, a cookbook of common samples, and technical videos.

We owe a particular debt to the early adopters who have joined us on the journey so far, providing feedback, identifying issues, creating content, and generally shaping the product. The Flutter community is one of our greatest assets as a project: a welcoming, diverse, helpful group of individuals who volunteer selflessly because they also care about this open source project. Thank you!

Flutter is ready for you. What will you build?

Flutter Release Preview 2: Pixel-Perfect on iOS

Posted by the Flutter Team at Google

Flutter is Google's new mobile app toolkit for crafting beautiful native interfaces on iOS and Android in record time. Today, during the keynote of Google Developer Days in Shanghai, we are announcing Flutter Release Preview 2: our last major milestone before Flutter 1.0.

This release continues the work of completing core scenarios and improving quality, beginning with our initial beta release in February through to the availability of our first Release Preview earlier this summer. The team is now fully focused on completing our 1.0 release.

What's New in Release Preview 2

The theme for this release is pixel-perfect iOS apps. While we designed Flutter with highly brand-driven, tailored experiences in mind, we heard feedback from some of you who wanted to build applications that closely follow the Apple interface guidelines. So in this release we've greatly expanded our support for the "Cupertino" themed controls in Flutter, with an extensive library of widgets and classes that make it easier than ever to build with iOS in mind.

A reproduction of the iOS Settings home page, built with Flutter

Here are a few of the new iOS-themed widgets added in Flutter Release Preview 2:

And more have been updated, too:

As ever, the Flutter documentation is the place to go for detailed information on the Cupertino* classes. (Note that at the time of writing, we were still working to add some of these new Cupertino widgets to the visual widget catalog).

We've made progress to complete other scenarios also. Taking a look under the hood, support has been added for executing Dart code in the background, even while the application is suspended. Plugin authors can take advantage of this to create new plugins that execute code upon an event being triggered, such as the firing of a timer, or the receipt of a location update. For a more detailed introduction, read this Medium article, which demonstrates how to use background execution to create a geofencing plugin.

Another improvement is a reduction of up to 30% in our application package size on both Android and iOS. Our minimal Flutter app on Android now weighs in at just 4.7MB when built in release mode, a savings of 2MB since we started the effort — and we're continuing to identify further potential optimizations. (Note that while the improvements affect both iOS and Android, you may see different results on iOS because of how iOS packages are built).

Growing Momentum

As many new developers continue to discover Flutter, we're humbled to note that Flutter is now one of the top 50 active software repositories on GitHub:

We declared Flutter "production ready" at Google I/O this year; with Flutter getting ever closer to the stable 1.0 release, many new Flutter applications are being released, with thousands of Flutter-based apps already appearing in the Apple and Google Play stores. These include some of the largest applications on the planet by usage, such as Alibaba (Android, iOS), Tencent Now (Android, iOS), and Google Ads (Android, iOS). Here's a video on how Alibaba used Flutter to build their Xianyu app (Android, iOS), currently used by over 50 million customers in China:

We take customer satisfaction seriously and regularly survey our users. We promised to share the results back with the community, and our most recent survey shows that 92% of developers are satisfied or very satisfied with Flutter and would recommend Flutter to others. When it comes to fast development and beautiful UIs, 79% found Flutter extremely helpful or very helpful in both reaching their maximum engineering velocity and implementing an ideal UI. And 82% of Flutter developers are satisfied or very satisfied with the Dart programming language, which recently celebrated hitting the release milestone for Dart 2.

Flutter's strong community growth can be felt in other ways, too. On StackOverflow, we see fast growing interest in Flutter, with lots of new questions being posted, answered and viewed, as this chart shows:

Number of StackOverflow question views tagged with each of four popular UI frameworks over time

Flutter has been open source from day one. That's by design. Our goal is to be transparent about our progress and encourage contributions from individuals and other companies who share our desire to see beautiful user experiences on all platforms.

Getting Started

How do you upgrade to Flutter Release Preview 2? If you're on the beta channel already, it just takes one command: 

$ flutter upgrade

You can check that you have Release Preview 2 installed by running flutter --version from the command line. If you have version 0.8.2 or later, you have everything described in this post.

If you haven't tried Flutter yet, now is the perfect time, and flutter.io has all the details to download Flutter and get started with your first app.

When you're ready, there's a whole ecosystem of example apps and code snippets to help you get going. You can find samples from the Flutter team in the flutter/samples repo on GitHub, covering things like how to use Material and Cupertino, approaches for deserializing data encoded in JSON, and more. There's also a curated list of samples that links out to some of the best examples created by the Flutter community.

You can also learn and stay up to date with Flutter through our hands-on videos, newsletters, community articles and developer shows. There are discussion groups, chat rooms, community support, and a weekly online hangout available to you to help you along the way as you build your application. Release Preview 2 is our last release preview. Next stop: 1.0!

Flutter Release Preview 1: Live from GMTC in Beijing

Posted by the Flutter Team at Google

Today at the GMTC front-end conference in Beijing, we announced Flutter Release Preview 1, signaling a new phase of development for Flutter as we move into the final stages of stabilization for 1.0.

Google I/O last month was something of a celebration for the Flutter team: having reached beta, it was good to meet with many developers who are learning, prototyping, or building with Flutter. In the immediate aftermath of Google I/O, we continue to see rapid growth in the Flutter ecosystem, with a 50% increase in active Flutter users. We've also seen over 150 individual Flutter events taking place across fifty countries: from New York City to Uyo, Nigeria; from Tokyo and Osaka in Japan to Nuremberg, Germany.

One common measure of community momentum is the number of GitHub stars, and we've also seen tremendous growth here, with Flutter becoming one of the top 100 software repos on GitHub in May.

Announcing Flutter Release Preview 1

Today we're taking another big step forward, with the immediate availability of Flutter Release Preview 1. It seems particularly auspicious to make this announcement in Beijing at the GMTC Global Front-End Conference. China has the third largest population of developers using Flutter, after the USA and India. Companies such as Alibaba and Tencent are already adopting Flutter for production apps, and there is a growing local community who are translating content and adding packages and mirrors for Chinese developers.

The shift from beta to release preview with this release signals our confidence in the stability and quality of what we have with Flutter, and our focus on bug fixing and stabilization.

We've posted a longer article with details on what's new in Flutter Release Preview 1 over at our Medium channel. You can download Flutter Release Preview 1 directly from the Flutter website, or simply run flutter upgrade from an existing installation.

It's been fun to watch others encounter Flutter for the first time. This article from an iOS developer who has recently completed porting an iOS app to Flutter is a positive endorsement of the project's readiness for real-world production usage:

"I haven't been this excited about a technology since Ruby on Rails or Go… After dedicating years to learning iOS app dev in-depth, it killed me that I was alienating so many Android friends out there. Also, learning other cross platform frameworks at the time was super unattractive to me because of what was available… Writing a Flutter app has been a litmus test and Flutter passed the test. Flutter is something I feel like I can really invest in and most importantly, really enjoy using."

As we get ever closer to publishing our first release from the "stable" channel, we're ready for more developers to build and deploy solutions that use this Release Preview. There are plenty of training offerings to help you learn Flutter: from I/O sessions to newsletters to hands-on videos to developer shows. We're excited to see what you build!

[Video] Hamilton app built in 3 months with Flutter reaches 1M+ installs

Originally posted on Flutter's Medium by Martin Aguinis

Hamilton and Posse, a design and development agency in New York, had three short months to develop and launch mobile apps for the hit Broadway show. How did they accomplish that? Using Flutter, Google's new mobile UI framework.

Reaching millions of users — with an outstanding half a million monthly active users and featured on both the App Store and Google Play— the apps let fans enter the ticket lottery, buy merchandise, play trivia, take selfies with a #HamCam, read frequently updated news and interviews, and more.

Watch this video case study to see how Flutter continues to help apps like Hamilton succeed on iOS and Android. You can read more details about the development of this app on Posse's blog post.

Flutter is free and open source. Get started today at flutter.io. We can't wait to see what you build!

Announcing Flutter beta 1: Build beautiful native apps

Originally posted on Flutter's Medium by Seth Ladd

Today, as part of Mobile World Congress 2018, we are excited to announce the first beta release of Flutter. Flutter is Google's new mobile UI framework that helps developers craft high-quality native interfaces for both iOS and Android. Get started today at flutter.io to build beautiful native apps in record time.

Flutter targets the sweet spot of mobile development: performance and platform integrations of native mobile, with high-velocity development and multi-platform reach of portable UI toolkits.

Designed for both new and experienced mobile developers, Flutter can help you build beautiful and successful apps in record time with benefits such as:

  • High-velocity development with features like stateful Hot Reload, a new reactive framework, rich widget set, and integrated tooling.
  • Expressive and flexible designs with composible widget sets, rich animation libraries, and a layered, extensible architecture.
  • High-quality experiences across devices and platforms with our portable, GPU-accelerated renderer and high-performance, native ARM code runtime, and platform interop.

Since our alpha release last year, we delivered, with help from our community, features such as screen reader support and other accessibility features, right-to-left text, localization and internationalization, iPhone X and iOS 11 support, inline video, additional image format support, running Flutter code in the background, and much more.

Our tools also improved significantly, with support for Android Studio, Visual Studio Code, new refactorings to help you manage your widget code, platform interop to expose the power of mobile platforms to Flutter code, improved stateful hot reloads, and a new widget inspector to help you browse the widget tree.

Thanks to the many new features across the framework and tools, teams across Google (such as AdWords) and around the world have been successful with Flutter. Flutter has been used in production apps with millions of installs, apps built with Flutter have been featured in the App Store and Play Store (for example, Hamilton: The Musical), and startups and agencies have been successful with Flutter.

For example, Codemate, a development agency in Finland, attributes Flutter's high-velocity dev cycle and customizable UI toolkit to their ability to quickly build a beautiful app for Hookle. "We now confidently recommend Flutter to help our clients perform better and deliver more value to their users across mobile," said Toni Piirainen, CEO of Codemate.

Apps built with Flutter deliver quality, performance, and customized designs across platforms.

Flutter's beta also works with a pre-release of Dart 2, with improved support for declaring UI in code with minimal language ceremony. For example, Dart 2 infers new and const to remove boilerplate when building UI. Here is an example: 


// Before Dart 2
Widget build(BuildContext context) {
  return new Container(
    height: 56.0,
    padding: const EdgeInsets.symmetric(horizontal: 8.0),
    decoration: new BoxDecoration(color: Colors.blue[500]),
    child: new Row(
      ...
    ),
  );
}

// After Dart 2
Widget build(BuildContext context) =>
  Container(
    height: 56.0,
    padding: EdgeInsets.symmetric(horizontal: 8.0),
    decoration: BoxDecoration(color: Colors.blue[500]),
    child: Row(
      ...
    ),
  );

widget.dart on GitHub

We're thrilled to see Flutter's ecosystem thriving. There are now over 1000 packages that work with Flutter (for example: SQLite, Firebase, Facebook Connect, shared preferences, GraphQL, and lots more), over 1700 people in our chat, and we're delighted to see our community launch new sites such as Flutter Institute, Start Flutter, and Flutter Rocks. Plus, you can now subscribe to the new Flutter Weekly newsletter, edited and published by our community.

As we look forward to our 1.0 release, we are focused on stabilization and scenario completion. Our roadmap, largely influenced by our community, currently tracks features such as making it easier to embed Flutter into an existing app, inline WebView, improved routing and navigation APIs, additional Firebase support, inline maps, a smaller core engine, and more. We expect to release new betas approximately every four weeks, and we highly encourage you to vote (?) on issues important to you and your app via our issue tracker.

Now is the perfect time to try Flutter. You can go from zero to your first running Flutter app quickly with our Getting Started guide. If you already have Flutter installed, you can switch to the beta channel using these instructions.

We want to extend our sincere thanks for your support, feedback, and many contributions. We look forward to continuing this journey with everyone, and we can't wait to see what you build!

Hello, developers in China! This post is also available in Chinese.

Hamilton App Takes the Stage

Posted by David DeRemer (from Posse)

Whether it's opening night for a Broadway musical or launch day for your app, both are thrilling times for everyone involved. Our agency, Posse, collaborated with Hamilton to design, build, and launch the official Hamilton app... in only three short months.

We decided to use Firebase, Google's mobile development platform, for our backend and infrastructure, while we used Flutter, a new UI toolkit for iOS and Android, for our front-end. In this post, we share how we did it.

The Cloud Where It Happens

We love to spend time designing beautiful UIs, testing new interactions, and iterating with clients, and we don't want to be distracted by setting up and maintaining servers. To stay focused on the app and our users, we implemented a full serverless architecture and made heavy use of Firebase.

A key feature of the app is the ticket lottery, which offers fans a chance to get tickets to the constantly sold-out Hamilton show. We used Cloud Functions for Firebase, and a data flow architecture we learned about at Google I/O, to coordinate the lottery workflow between the mobile app, custom business logic, and partner services.

For example, when someone enters the lottery, the app first writes data to specific nodes in Realtime Database and the database's security rules help to ensure that the data is valid. The write triggers a Cloud Function, which runs business logic and stores its result to a new node in the Realtime Database. The newly written result data is then pushed automatically to the app.

What'd I miss?

Because of Hamilton's intense fan following, we wanted to make sure that app users could get news the instant it was published. So we built a custom, web-based Content Management System (CMS) for the Hamilton team that used Firebase Realtime Database to store and retrieve data. The Realtime Database eliminated the need for a "pull to refresh" feature of the app. When new content is published via the CMS, the update is stored in Firebase Realtime Database and every app user automatically sees the update. No refresh, reload, or pull required!

Cloud Functions Left Us Satisfied

Besides powering our lottery integration, Cloud Functions was also extremely valuable in the creation of user profiles, sending push notifications, and our #HamCam — a custom Hamilton selfie and photo-taking experience. Cloud Functions resized the images, saved them in Cloud Storage, and then updated the database. By taking care of the infrastructure work of storing and managing the photos, Firebase freed us up to focus on making the camera fun and full of Hamilton style.

Developing UI? Don't Wait For It.

With only three months to design and deliver the app, we knew we needed to iterate quickly on the UX and UI. Flutter's hot reload development cycle meant we could make a change in our UI code and, in about a second, see the change reflected on our simulators and phones. No rebuilding, recompiling, or multi-second pauses required! Even the state of the app was preserved between hot reloads, making it very fast for us to iterate on the UI with our designers.

We used Flutter's reactive UI framework to implement Hamilton's iconic brand with custom UI elements. Flutter's "everything is a widget" approach made it easy for us to compose custom UIs from a rich set of building blocks provided by the framework. And, because Flutter runs on both iOS and Android, we were able to spend our time creating beautiful designs instead of porting the UI.

The FlutterFireproject helped us access Firebase Analytics, Firebase Authentication, and Realtime Database from the app code. And because Flutter is open source, and easy to extend, we even built a custom router library that helped us organize the app's UI code.

What comes next?

We enjoyed building the Hamilton app in a way that allowed us to focus on our users and experiment with new app ideas and experiences. And based on our experience, we'd happily recommend serverless architectures with Firebase and customized UI designs with Flutter as powerful ways for you to save time building your app.

For us, we already have plans how to continue and develop Hamilton app in new ways, and can't wait to release those soon!

If you want to learn more about Firebase or Flutter, we recommend the Firebase docs, the Firebase channel on YouTube, and the Flutter website.

Dart in 2017 and beyond

We’re here at the Dart Developer Summit in Munich, Germany. Over 250 developers from more than 50 companies from all over the world just finished watching the keynote.

This is a summary of the topics we covered:

Dart is the fastest growing programming language at Google, with a 3.5x increase in lines of code since last year. We like to think that this is because of our focus on developer productivity: teams report 25% to 100% increase in speed of development. Google has bet its biggest business on Dart — the web apps built on Dart bring over $70B per year.

Google AdSense recently launched a ground-up redesign of their web app, built with Dart. Earlier this year, we announced that the next generation of AdWords is built with Dart. There are more exciting Dart products at Google that we’re looking forward to reveal. Outside Google, companies such as Wrike, Workiva, Soundtrap, Blossom, DG Logic, Sonar Design have all been using and enjoying Dart for years.

Our five year investment in this language is reaping fruit. But we’re not finished.

We learned that people who use Dart love its terse and readable syntax. So we’re keeping that.

We have also learned that Dart developers really enjoy the language’s powerful static analysis. So we’re making it better. With strong mode, Dart’s type system becomes sound (meaning that it rejects all incorrect programs). We’re also introducing support for generic methods.

We have validated that the programming language itself is just a part of the puzzle. Dart comes with ‘batteries included.’ Developers really like Dart’s core libraries — we will keep them tight, efficient and comprehensive. We will also continue to invest in tooling such as pub (our integrated packaging system), dartfmt (our automatic formatter) and, of course, the analyzer.

On the web, we have arrived at a framework that is an excellent fit for Dart: AngularDart. All the Google web apps mentioned above use it. It has been in production at Google since February. AngularDart is designed for Dart, and it’s getting better every week. In the past 4 months, AngularDart’s output has gotten 40% smaller, and our AngularDart web apps got 15% faster.

Today, we’re launching AngularDart 2.0 final. Tune in to the next session.

With that, we’re also releasing — as a developer preview — the AngularDart components that Google uses for its major web apps. These Material Design widgets are being developed by hundreds of Google engineers and are thoroughly tested. They are written purely in Dart.

We’re also making Dart easier to use with existing JavaScript libraries. For example, you will be able to use our tool to convert TypeScript .d.ts declarations into Dart libraries.

We’re making the development cycle much faster. Thanks to Dart Dev Compiler, compilation to JavaScript will take less than a second across all modern browsers.

We believe all this makes Dart an even better choice for web development than before. Dart has been here for a long time and it’s not going anywhere. It’s cohesive and dependable, which is what a lot of web developers want.

We’re also very excited about Flutter — a project to help developers build high-performance, high-fidelity, mobile apps for iOS and Android from a single codebase in Dart. More on that tomorrow.

We hope you’ll enjoy these coming two days. Tune in on the live stream or follow #dartsummit on Twitter.

By Filip Hracek, Developer Relations Program Manager