text
stringlengths
1
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),
);
}
}<code_end>
Run the app (or stop and restart it, if it was already running
before adding the plugin). Click Show Flutter homepage.
You should see the default browser open on the device,
displaying the homepage for flutter.dev.
<topic_end>
<topic_start>Developing packages & plugins
<topic_end>
<topic_start>
Package introduction
Packages enable the creation of modular code that can be shared easily.
A minimal package consists of the following:info Note
For a list of dos and don’ts when writing an effective plugin,
see the Medium article by Mehmet Fidanboylu,
Writing a good plugin.<topic_end>
<topic_start>
Package types
Packages can contain more than one kind of content:Plugin packages can be written for Android
(using Kotlin or Java), iOS (using Swift or Objective-C),
web, macOS, Windows, or Linux, or any combination
thereof.A concrete example is the url_launcher plugin package.
To see how to use the url_launcher package, and how it
was extended to implement support for web,
see the Medium article by Harry Terkelsen,
How to Write a Flutter Web Plugin, Part 1.<topic_end>
<topic_start>
Developing Dart packages
The following instructions explain how to write a Flutter
package.<topic_end>
<topic_start>
Step 1: Create the package
To create a starter Flutter package,
use the --template=package flag with flutter create:This creates a package project in the hello
folder with the following content:<topic_end>
<topic_start>
Step 2: Implement the package
For pure Dart packages, simply add the functionality
inside the main lib/<package name>.dart file,
or in several files in the lib directory.To test the package, add unit tests
in a test directory.For additional details on how to organize the
package contents,
see the Dart library package documentation.<topic_end>
<topic_start>
Developing plugin packages
If you want to develop a package that calls into
platform-specific APIs,
you need to develop a plugin package.The API is connected to the platform-specific
implementation(s) using a platform channel.<topic_end>
<topic_start>
Federated plugins
Federated plugins are a way of splitting support for
different platforms into separate packages.
So, a federated plugin can use one package for iOS,
another for Android, another for web,
and yet another for a car (as an example of an IoT device).
Among other benefits, this approach allows a domain expert
to extend an existing plugin to work for the platform they know best.A federated plugin requires the following packages:<topic_end>
<topic_start>Endorsed federated plugin
Ideally, when adding a platform implementation to
a federated plugin, you will coordinate with the package
author to include your implementation.
In this way, the original author endorses your
implementation.For example, say you write a foobar_windows
implementation for the (imaginary) foobar plugin.
In an endorsed plugin, the original foobar author
adds your Windows implementation as a dependency
in the pubspec for the app-facing package.
Then, when a developer includes the foobar plugin
in their Flutter app, the Windows implementation,
as well as the other endorsed implementations,
are automatically available to the app.<topic_end>
<topic_start>Non-endorsed federated plugin
If you can’t, for whatever reason, get your implementation
added by the original plugin author, then your plugin
is not endorsed. A developer can still use your
implementation, but must manually add the plugin
to the app’s pubspec file. So, the developer
must include both the foobar dependency and
the foobar_windows dependency in order to achieve
full functionality.For more information on federated plugins,
why they are useful, and how they are
implemented, see the Medium article by Harry Terkelsen,
How To Write a Flutter Web Plugin, Part 2.<topic_end>
<topic_start>
Specifying a plugin’s supported platforms
Plugins can specify the platforms they support by
adding keys to the platforms map in the
pubspec.yaml file. For example,
the following pubspec file shows the
flutter: map for the hello plugin,
which supports only iOS and Android:When adding plugin implementations for more platforms,
the platforms map should be updated accordingly.
For example, here’s the map in the pubspec file
for the hello plugin,
when updated to add support for macOS and web:<topic_end>
<topic_start>Federated platform packages
A platform package uses the same format,