One of Flutter's primary goals is to create a framework that allows you to develop apps from a single codebase that look and feel great on any platform.
This means that your app might appear on screens of many different sizes, from a watch, to a foldable phone with two screens, to a high def monitor.
Two terms that describe concepts for this scenario are
adaptive
and
responsive
. Ideally, you'd want your app to be
both
but what, exactly, does this mean? These terms are similar, but they are not the same.
Adaptive
and
responsive
can be viewed as separate dimensions of an app: you can have an adaptive app that is not responsive, or vice versa. And, of course, an app can be both, or neither.
- Responsive
- Typically, a
responsive
app has had its layout tuned for the available screen size. Often this means (for example), re-laying out the UI if the user resizes the window, or changes the device's orientation. This is especially necessary when the same app can run on a variety of devices, from a watch, phone, tablet, to a laptop or desktop computer.
- Adaptive
- Adapting
an app to run on different device types, such as mobile and desktop, requires dealing with mouse and keyboard input, as well as touch input. It also means there are different expectations about the app's visual density, how component selection works (cascading menus vs bottom sheets, for example), using platform-specific features (such as top-level windows), and more.
Learn more in the following 5-minute video:
Adaptive vs Responsive
Flutter allows you to create apps that self-adapt to the device's screen size and orientation.
There are two basic approaches to creating Flutter apps with responsive design:
- Use the
LayoutBuilder
class
- From its
builder
property, you get a
BoxConstraints
object. Examine the constraint's properties to decide what to display. For example, if your
maxWidth
is greater than your width breakpoint, return a
Scaffold
object with a row that has a list on the left. If it's narrower, return a
Scaffold
object with a drawer containing that list. You can also adjust your display based on the device's height, the aspect ratio, or some other property. When the constraints change (for example, the user rotates the phone, or puts your app into a tile UI on Android), the build function runs.
- Use the
MediaQuery.of()
method in your build functions
- This gives you the size, orientation, etc, of your current app. This is more useful if you want to make decisions based on the complete context rather than on just the size of your particular widget. Again, if you use this, then your build function automatically runs if the user somehow changes the app's size.
Other useful widgets and classes for creating a responsive UI:
For more information, here are a few resources, including contributions from the Flutter community:
Learn more about creating an adaptive Flutter app with
Building adaptive apps
, written by the gskinner team.
You might also check out the following episodes of The Boring Show:
Adaptive layouts
Adaptive layouts, part 2
For an excellent example of an adaptive app, check out Flutter Folio, a scrapbooking app created in collaboration with gskinner and the Flutter team:
The
Folio source code
is also available on GitHub. Learn more on the
gskinner blog
.
You can learn more about creating platform adaptive apps in the following resources:
