A responsive app supports devices with widely varying screen sizes. This is essential when the same app can run on a variety of devices, e.g., a phone, laptop, desktop computer, or tablet. Implementing responsive UIs in real life is not that easy. Using Flutter, let's make it simple. Everything in Flutter is a widget. Here we'll go through different widgets using which we can build responsive applications with Flutter. Three important things to consider while building an app with responsive design are the size, orientation, and device type. A change in any of these can change the app UI.
Responsive Design From a Business Perspective
Responsive design is a design and development technique that permits an application, website, or system to adjust to the size of a user’s screen. It will optimize a user’s browsing experience by providing a responsive Web page/application or application for the specific device.
Why is responsive design important in Flutter?
Some advantages come with having a Flutter application developed with a responsive design. Consistency in your application across variable screen sizes ensures that you have a wider range of users. Tablets and smaller mobile devices can provide the best-tailored user experience
In addition, the retention rate in your application is likely to be higher once you have developed an advanced responsive design. Since Flutter is the best choice for web and mobile apps, A responsive design guarantees that the appeal of your application is consistent and provides users with a seamless experience no matter the size of the device in use. It goes without saying that if you factor responsiveness into your application, it also shuts out negative ratings. There are more than 2 million applications on the App Store and more than 3 million more on the Google Play store. Most users form opinions about which applications to download based on reviews.
The concept of responsive design lies in utilizing one set of code that adapts to variable layout changes corresponding to various devices (smartphones, tablets, and desktop computers).
Important Factors in Flutter Designing
One of the important things we must consider while designing is the way of using widgets. The majority use hard-coded values with widgets, which results in apps that are poorly designed. Instead, a media query can be used to get the real-time size of the window.
To get Screen width: MediaQuery.of(context).size.width
To get Screen height:MediaQuery.of(context).size.height
Most of the responsive designs can be built using the following widgets:
Flexible and Expanded
These two widgets can be used to give flexibility to their children or to expand to fill the available space. The main difference between them is that the expanded widget needs the child to fill the available space, while the flexible widget does not. A flex value is given after wrapping a widget in expanded or flexible widgets.
Even if the extra property like flex is not given, the expanded widget will take the remaining space equally. The expanded child will use the free space. If more than one child is expanded, the space is equally shared. The default flex value is 1.
A flex factor is used if you want to specify a scale for the free space. A flex factor is a property of an expanded widget that specifies the sharing of the free space between child widgets and also its uses. A property called "fit" is used to specify how strict its size should be in the flexible widget. It can be either loose or tight. You can mix and match flexible ones with fixed-size widgets.
eg:Flexible(
child: Container(
color: Colors.red,
child: Text(
"Flexible",
),
),
);
eg:Expanded(
child: Container(
child: Center(
child: Text(
'Expaned widget',
style: TextStyle(
color: Colors.blue,
),
),
),
color: Colors.white,
width: 200,
),
);
FittedBox
Scale and position its child within itself according to fit and alignment. The BoxFit property describes how it should make its child fit, and it will scale or clip its child automatically. You can use different types of BoxFit:
- BoxFit.none
- BoxFit.contain
- BoxFit.fill
- BoxFit.cover
- BoxFit.fitWidth
- BoxFit.fitHeight
- BoxFit.scaleDown
eg:Container(
decoration: BoxDecoration(
border: Border.all(width: 3,
color: Colors.black),
),
child: FittedBox(fit: BoxFit.contain,
child: Text('This is fitted box')
),
width: 100,
height: 30,
LayoutBuilder
Determine the maximum width and height of a particular widget using the Box Constraints object. It has two parameters: build context and box constraints. BuildContext refers to a widget. The box constraint is of more importance; it gives the width to the parent widget and the child size will be managed according to this.
LayoutBuilder(builder: (context, constraints) {
return Container(...);
}
Orientation Builder
To determine the orientation of a widget, The orientation builder is somewhat similar to the layout builder. You'll get the Orientation object from its builder property. As an example, the number of columns in a grid view can be changed using orientation.
OrientationBuilder
(
builder : (context,orientation){
return GridView.count(
crossAxisCount : orientation==Orientation.portrait ? 2 : 3,
),
);
},
);
Fractionally Sized Box
It is mostly useful when used inside expanded or flexible widgets. The widget helps to size its children to a fraction of the total available space. Wrap the child you want to be sized with FractionallySizedBox.You can give a height factor and a width factor. Alignment is used to control the alignment of a fractionally sized widget.
Expanded
(
child: FractionallySizedBox(
alignment: Alignment.centerLeft,
widthFactor: widthFactor,
child: Container(
decoration: BoxDecoration(
color: Colors.amber,
border: Border.all(color: Colors.white),
),
child: Padding(
padding: const EdgeInsets.all(16.0),
child: Text(
'width',
style: TextStyle(color: Colors.blue, fontSize: 24),
),
),
),
),
);
Aspect Ratio
The size of the child is according to a specific aspect ratio. It's often written as a fraction, like 3/2, as in three parts of width to two parts of height.
AspectRatio(
aspectRatio: 3/2,
child: Container(
child: Padding(
padding: const EdgeInsets.all(6.0),
child: Center(
child: Text(
'AspectRatio',
style: TextStyle(color: Colors.blue, fontSize: 20),
),
),
),
),
);
In addition to these widgets, several other widgets and flutter packages are also available to make the app responsive. One among these is responsive_framework.
MaterialApp(
builder: (context, child) => ResponsiveWrapper.builder(
child,
maxWidth: 1200,
minWidth: 480,
defaultScale: true,
breakpoints: [
ResponsiveBreakpoint.resize(480, name: MOBILE),
ResponsiveBreakpoint.autoScale(800, name: TABLET),
ResponsiveBreakpoint.resize(1000, name: DESKTOP),
],
background: Container(color: Color(0xFFF5F5F5))),
initialRoute: "/",
);
Moreover, while working with complex designs such as grid views, we find difficulty in specifying the grid size. Most of you use a child aspect ratio to specify the size of grids. However, an easy way of giving a size for grids is the use of the package dynamic_height_grid_view.
DynamicHeightGridView(
itemCount: 120,
crossAxisCount: 3,
crossAxisSpacing: 10,
mainAxisSpacing: 10,
builder: (ctx, index) {
/// return your widget here.
}
);
I hope you understand how flutter can build responsive web applications. Sanesquare is a web application development company laser-focused on delivering top-quality services. If you need assistance with web application development, feel free to get in touch with us.
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