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Yesterday, Google announced Flutter Release Preview 2, during the keynote of Google Developer Days in Shanghai. This is the final preview before the Google team releases Flutter 1.0. In this preview release, they have expanded support for the “Cupertino” themed controls and executing Dart code in the background and reduced the package size.

Flutter is Google’s new open-source mobile app SDK using which you can quickly create high-quality native interfaces on iOS and Android.

What’s new in Flutter Release Preview 2?

Extended support for Cupertino themed controls

After getting the feedback on Flutter Release Preview 1, this release is designed with keeping Apple interface guidelines in mind. They have expanded support for the “Cupertino” themed controls in Flutter, with an extensive library of widgets and classes. Some of the added iOS-themed widgets are:

  • CupertinoApp, a convenience widget that wraps a number of widgets that are commonly required for an iOS-design targeting application.
  • CupertinoTimerPicker is used to show countdown duration with hour, minute and second spinners.
  • CupertinoSegmentedControl displays the widgets provided in the Map of children in a horizontal list. It is used to select between a number of mutually exclusive options.
  • CupertinoActionSheet is used for a specific style of alert that presents the user with a set of two or more choices related to the current context.

Support for executing Dart code in the background

In this release, support has been added for executing Dart code in the background, even while the application is suspended.  


Reduced package size

The application package size is now reduced by up to 30% on both Android and iOS. A minimal Flutter app on Android now weighs just 4.7 MB when built in release mode, and they are continually working towards identifying further potential optimizations.

How to upgrade to Flutter Release Preview 2?

If you’re using the beta release already, you can upgrade to Flutter Release Preview 2 just by running the following:

$ flutter upgrade

Follow the instructions mentioned on the Flutter blog for upgrading to Flutter Release Preview 2.

To know more about Flutter Preview 2 in detail, check out the official announcement by Google.

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