How to improve your Flutter application with gradient designs
Spice up your app's aesthetic with this simple tutorial on gradient designs
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Gradients are beautiful design elements that are experiencing a revival in the designing world. Large companies, including Hulu and Spotify, frequently use such designs in their products. This article will teach you how to add and customize these gradient designs into your Flutter app.
Linear Gradients
As per its name, this gradient flows over a simple linear stretch. Over this stretch is a smooth color transition. An example follows:
As you can see, the color changes in a linear manner from left to right. Linear gradients can be modified so that this color transition occurs in a different direction. The following example demonstrates a linear gradient that is aligned from the bottomLeft to the topRight:
Here’s how to code a linear gradient in Flutter:
Container(
decoration: BoxDecoration(
gradient: LinearGradient(
begin: Alignment.centerLeft,
end: Alignment.centerRight,
colors: [Colors.purple, Colors.blue])
),
)If you do not specify the “begin” or the “end” property in the constructor, the default will be from centerLeft to centerRight, like the first example in this section.
Here’s the full code for a sample app with a simple linear gradient:
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Gradient Demo',
home: Scaffold(
appBar: AppBar(
title: const Text('Flutter Gradient Demo'),
),
body: Center(
child: Container(
decoration: BoxDecoration(
gradient: LinearGradient(
begin: Alignment.centerLeft,
end: Alignment.centerRight,
colors: [Colors.purple, Colors.blue])))),
));
}
}
There are multiple ways to customize your gradient. Let’s start by adding two more colors and changing the direction of the gradient:
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Gradient Demo',
home: Scaffold(
appBar: AppBar(
title: const Text('Flutter Gradient Demo'),
),
body: Center(
child: Container(
decoration: BoxDecoration(
gradient: LinearGradient(
begin: Alignment.bottomLeft,
end: Alignment.topRight,
colors: [Colors.red, Colors.yellow, Colors.blue, Colors.purple])))),
));
}
}
The linear gradient above follows a uniform distribution; by adding stops into our code, we can adjust the distribution of each color in the gradient. Each value in the array of stop values controls how prevalent each color is in the gradient. Here’s the code for the same linear gradient with some stop values:
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Gradient Demo',
home: Scaffold(
appBar: AppBar(
title: const Text('Flutter Gradient Demo'),
),
body: Center(
child: Container(
decoration: BoxDecoration(
gradient: LinearGradient(
begin: Alignment.bottomLeft,
end: Alignment.topRight,
// Add one stop for each color
// Values should increase from 0.0 to 1.0
stops: [0.1, 0.5, 0.8, 0.9],
colors: [Colors.red, Colors.yellow, Colors.blue, Colors.purple])))),
));
}
}The corresponding linear gradient:
Radial Gradients
These types of gradients change color based on a pixel’s location from a central point, hence the name “radial”.
Here’s how to code a basic radial gradient in Flutter:
Container(
decoration: BoxDecoration(
gradient: RadialGradient(
colors: [Colors.yellow, Colors.deepPurple],
),
),
),Here’s the full code for a sample app with a simple radial gradient:
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Gradient Demo',
home: Scaffold(
appBar: AppBar(
title: const Text('Flutter Gradient Demo'),
),
body: Center(
child: Container(
decoration: BoxDecoration(
gradient: RadialGradient(
colors: [Colors.yellow, Colors.deepPurple],
),
),
),
),
));
}
}
Similar to linear gradients, radial gradients can also be customized by a multitude of methods:
Colors and Stops
As we have done with linear gradients, we can add multiple colors or add stops to our radial gradients. In this case, stops specify decimal values of the radius between 0.0 and 1.0, giving concentric rings for each color. If stops are not specified, a uniform distribution is assumed. Here’s an example of a multicolored radial gradient with stops:
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Gradient Demo',
home: Scaffold(
appBar: AppBar(
title: const Text('Flutter Gradient Demo'),
),
body: Center(
child: Container(
decoration: BoxDecoration(
gradient: RadialGradient(
colors: [Colors.yellow, Colors.red, Colors.purple],
// Add one stop for each color
// Values should increase from 0.0 to 1.0
stops: [0.1, 0.5, 0.75]
),
),
),
),
));
}
}
Center
In the examples above, the center point of the radial gradient was in the middle of the screen. If you want to modify the center of the gradient, you must specify the center property in the Radial Gradient constructor. Remember, if you don’t define this property, the default places the gradient in the center of the screen
center: Alignment(0.x, 0.y)Here’s a helpful image explaining the alignment in Flutter:
Here’s an example of a radial gradient with an adjusted center:
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Gradient Demo',
home: Scaffold(
appBar: AppBar(
title: const Text('Flutter Gradient Demo'),
),
body: Center(
child: Container(
decoration: BoxDecoration(
gradient: RadialGradient(
colors: [Colors.yellow, Colors.red, Colors.purple],
center: Alignment(1.0, 1.0),
),
),
),
),
));
}
}If you look at the graph, aligning the center of the radial gradient means that it should be shifted to the bottom right corner.
We can also adjust the focal point of the gradient within the radius by defining another property in the RadialGradient constructor:
focal: Alignment(0.x, 0.y),Here’s the full code for a sample app with a radial gradient that has an adjusted focal point:
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Gradient Demo',
home: Scaffold(
appBar: AppBar(
title: const Text('Flutter Gradient Demo'),
),
body: Center(
child: Container(
decoration: BoxDecoration(
gradient: RadialGradient(
colors: [Colors.yellow, Colors.red,Colors.purple],
center: Alignment(0.6, -0.3),
focal: Alignment(0.3, -0.1),
),
),
),
),
));
}
}
To adjust the radius of the focal point in the middle of the radial gradient, we need to define the focalRadius property in the RadialGradient constructor:
decoration: BoxDecoration(
gradient: RadialGradient(
colors: [Colors.yellow, Colors.red,Colors.purple],
...
focalRadius: 1.0,
),
),Here’s the code for the previous radial gradient with an adjusted focal radius:
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Gradient Demo',
home: Scaffold(
appBar: AppBar(
title: const Text('Flutter Gradient Demo'),
),
body: Center(
child: Container(
decoration: BoxDecoration(
gradient: RadialGradient(
colors: [Colors.yellow, Colors.red,Colors.purple],
center: Alignment(0.6, -0.3),
focal: Alignment(0.3, -0.1),
focalRadius: 1.0,
),
),
),
),
));
}
}
Sweep Gradients:
This is a type of gradient that “sweeps” around a focal point forming a color gradient. Here’s an example:
Here’s the code for the sweep gradient above:
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Gradient Demo',
home: Scaffold(
appBar: AppBar(
title: const Text('Flutter Gradient Demo'),
),
body: Center(
child: Container(
decoration: BoxDecoration(
gradient: SweepGradient(
colors: [Colors.yellow,Colors.green, Colors.blue],
),
),
),
),
));
}
}As you can see, we’ve already added multiple colors in the sweep gradient. Just like the examples we’ve seen, we can also customize this gradient by adding stops:
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Gradient Demo',
home: Scaffold(
appBar: AppBar(
title: const Text('Flutter Gradient Demo'),
),
body: Center(
child: Container(
decoration: BoxDecoration(
gradient: SweepGradient(
colors: [Colors.yellow, Colors.green,Colors.blue],
stops: [0.1, 0.6, 0.9],
),
),
),
),
));
}
}
We can customize sweep gradients in a way that we haven’t seen in other gradients — by defining the start and stop angles that define its boundaries.
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Gradient Demo',
home: Scaffold(
appBar: AppBar(
title: const Text('Flutter Gradient Demo'),
),
body: Center(
child: Container(
decoration: BoxDecoration(
gradient: SweepGradient(
colors: [Colors.yellow, Colors.green,Colors.blue],
stops: [0.1, 0.6, 0.9],
startAngle: 0.9,
endAngle: 1.2,
),
),
),
),
));
}
}
You can always adjust the angles and experiment to create the design you want.
Bonus
All the gradients and customization we discussed can also be applied to the AppBar using the flexibleSpace property of the AppBar’s constructor. Here’s an example:
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Gradient Demo',
home: Scaffold(
appBar: AppBar(
title: Text('Gradient App Bar'),
flexibleSpace: Container(
decoration: BoxDecoration(
gradient: LinearGradient(
colors: [Colors.red, Colors.orange],
),
),
),
)
));
}
}
This trick isn’t limited to just linear gradients; You can also add and customize radial and sweep gradients as you wish. However, linear gradients tend to be the most suitable when customizing the app bar.
I hope you were able to find this article helpful in teaching you how to add gradients to your Flutter application, along with different ways to customize each type of gradient.
All the code used in this article (and other articles) can be found in my GitHub repo.
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