Как изменить шрифт flutter

Although Android and iOS offer high quality system fonts,
one of the most common requests from designers is for custom fonts.
For example, you might have a custom-built font from a designer,
or perhaps you downloaded a font from Google Fonts.

Flutter works with custom fonts and you can apply a custom
font across an entire app or to individual widgets.
This recipe creates an app that uses custom fonts with
the following steps:

1. Import the font files.
2. Declare the font in the pubspec.
3. Set a font as the default.
4. Use a font in a specific widget.

1. Import the font files

To work with a font, import the font files into the project.
It’s common practice to put font files in a fonts or assets
folder at the root of a Flutter project.

For example, to import the Raleway and Roboto Mono font
files into a project, the folder structure might look like this:

awesome_app/
  fonts/
    Raleway-Regular.ttf
    Raleway-Italic.ttf
    RobotoMono-Regular.ttf
    RobotoMono-Bold.ttf

Supported font formats

Flutter supports the following font formats:

• .ttc
• .ttf
• .otf

Flutter does not support .woff and .woff2 fonts for all platforms.

2. Declare the font in the pubspec

Once you’ve identified a font, tell Flutter where to find it.
You can do this by including a font definition in the pubspec.yaml file.

flutter:
  fonts:
    - family: Raleway
      fonts:
        - asset: fonts/Raleway-Regular.ttf
        - asset: fonts/Raleway-Italic.ttf
          style: italic
    - family: RobotoMono
      fonts:
        - asset: fonts/RobotoMono-Regular.ttf
        - asset: fonts/RobotoMono-Bold.ttf
          weight: 700

pubspec.yaml option definitions

The family determines the name of the font, which you use in the
fontFamily property of a TextStyle object.

The asset is a path to the font file,
relative to the pubspec.yaml file.
These files contain the outlines for the glyphs in the font.
When building the app,
these files are included in the app’s asset bundle.

A single font can reference many different files with different
outline weights and styles:

• The weight property specifies the weight of the outlines in
  the file as an integer multiple of 100, between 100 and 900.
  These values correspond to the FontWeight and can be used in the
  fontWeight property of a TextStyle object.
  For example, if you want to use the RobotoMono-Bold font defined above,
  you would set fontWeight to FontWeight.w700 in your TextStyle.

  Note that defining the weight property does not
  override the actual weight of the font. You would not be able to
  access RobotoMono-Bold with FontWeight.w100, even if its weight
  was set to 100.

• The style property specifies whether the outlines in the file are
  italic or normal.
  These values correspond to the FontStyle and can be used in the
  fontStyle property of a TextStyle object.
  For example, if you want to use the Raleway-Italic font defined above,
  you would set fontStyle to FontStyle.italic in your TextStyle.

  Note that defining the style property does not
  override the actual style of the font; You would not be able to
  access Raleway-Italic with FontStyle.normal, even if its style
  was set to normal.

3. Set a font as the default

You have two options for how to apply fonts to text: as the default font
or only within specific widgets.

To use a font as the default, set the fontFamily property
as part of the app’s theme. The value provided to
fontFamily must match the family
name declared in the pubspec.yaml.

return MaterialApp(
  title: 'Custom Fonts',
  // Set Raleway as the default app font.
  theme: ThemeData(fontFamily: 'Raleway'),
  home: const MyHomePage(),
);

For more information on themes,
see the Using Themes to share colors and font styles recipe.

If you want to apply the font to a specific widget,
such as a Text widget,
provide a TextStyle to the widget.

In this example, apply the RobotoMono font to a single Text widget.
Once again, the fontFamily must match the family name declared in the
pubspec.yaml.

child: Text(
  'Roboto Mono sample',
  style: TextStyle(fontFamily: 'RobotoMono'),
),

TextStyle

If a TextStyle object specifies a weight
or style for which there is no exact font file,
the engine uses one of the more generic files
for the font and attempts to extrapolate outlines
for the requested weight and style.

Complete example

Fonts

The Raleway and RobotoMono fonts were downloaded from
Google Fonts.

pubspec.yaml

name: custom_fonts
description: An example of how to use custom fonts with Flutter

dependencies:
  flutter:
    sdk: flutter

dev_dependencies:
  flutter_test:
    sdk: flutter

flutter:
  fonts:
    - family: Raleway
      fonts:
        - asset: fonts/Raleway-Regular.ttf
        - asset: fonts/Raleway-Italic.ttf
          style: italic
    - family: RobotoMono
      fonts:
        - asset: fonts/RobotoMono-Regular.ttf
        - asset: fonts/RobotoMono-Bold.ttf
          weight: 700
  uses-material-design: true

main.dart

import 'package:flutter/material.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Custom Fonts',
      // Set Raleway as the default app font.
      theme: ThemeData(fontFamily: 'Raleway'),
      home: const MyHomePage(),
    );
  }
}

class MyHomePage extends StatelessWidget {
  const MyHomePage({super.key});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      // The AppBar uses the app-default Raleway font.
      appBar: AppBar(title: const Text('Custom Fonts')),
      body: const Center(
        // This Text widget uses the RobotoMono font.
        child: Text(
          'Roboto Mono sample',
          style: TextStyle(fontFamily: 'RobotoMono'),
        ),
      ),
    );
  }
}

Customization is everywhere, from documents to apps, we can customize everything as we want to. The power of customization is humongous, and it has revolutionized the way we look at technology in this world. Just like how printing “Hello World”, is the basic step towards learning a new programming language, customizing the style of a text is the basic step toward customizing an app. So, let’s see how to customize text in Flutter.

Basic Flutter App:

In Flutter, everything is a widget. So, “Text” is a widget too. The text widget has its own properties like font style, font size, font-weight, etc. The Flutter team has set a few default properties before making things easier for the user to create apps. So, customizing text is all about editing these properties as we want, to get the desired output.

Now, let’s create a basic Flutter app with various default Text widget properties available.

 Output: 

Custom Fonts in Flutter:

Download Font File: A Font file has all the required details regarding a font family, so once imported the font style can be used throughout the app. Google Fonts website has a wide variety of font families that can be downloaded and used in an app. The steps for downloading the file are as follows: 

• Step 1: Open Google Fonts and search for a font family in the search bar (here “Pacifico”).
• Step 2: Select the “Pacifico” font file.
• Step 3: To download, click the “Download Family” button.

Import Font Files: To use the downloaded font family, we need to import the font file into the root of the Flutter app. The steps for importing the font file in Android Studio are as follows: 

• Step 1: Click the “Project” button in the top left corner of Android Studio.
• Step 2: Right-click on the project name, here “gfg_custom_fonts” and select New + Directory.
• Step 3: Name the directory as “fonts“.
• Step 4: Open file manager and go to downloads. Extract and open the “Pacifico” zip file.
• Step 5: Move the “Pacifico Regular” file into this directory. After moving, the font directory contains a file named “Pacifico-Regular.ttf”.

Declare Font: Now after importing the font file, it’s a necessity to tell Flutter where to fetch the font file from. So, it’s a need to declare the font in a specific file named “pubspec.yaml” file. Indentation plays a major role in this file, where double-space is used to indent the code. The steps to declare the font file is as follows: 

• Step 1: Click the “Project” button and click on the project name, here “gfg_custom_fonts”.
• Step 2:  In the list, there is a file called “pubspec.yaml” file. Click this file.
• Step 3: Paste the below code in the pubspec.yaml file. Be aware of the indentations.
• Step 4: Press the “Pub get” button in the top right corner of the file.

Add Font Family: Now this font family can be used in styling the text widget in the app wherever needed. Not only one, but multiple families can be downloaded in the above-mentioned steps. 

Note: The name mentioned in the “family:” of the “pubspec.yaml” file should be unique for different font families. In order to use this font, the font family property of the text widget is used in the .dart file. 

The syntax for it is as follows: 

Text('text',
             style: TextStyle(
               fontFamily: 'family_name',
             ),
           ),

Complete Source Code: The final code after customizing the text style is as follows:

Output: 

Customization is everywhere, from documents to apps, we can customize everything as we want to. The power of customization is humongous, and it has revolutionized the way we look at technology in this world. Just like how printing “Hello World”, is the basic step towards learning a new programming language, customizing the style of a text is the basic step toward customizing an app. So, let’s see how to customize text in Flutter.

Basic Flutter App:

In Flutter, everything is a widget. So, “Text” is a widget too. The text widget has its own properties like font style, font size, font-weight, etc. The Flutter team has set a few default properties before making things easier for the user to create apps. So, customizing text is all about editing these properties as we want, to get the desired output.

Now, let’s create a basic Flutter app with various default Text widget properties available.

 Output: 

Custom Fonts in Flutter:

Download Font File: A Font file has all the required details regarding a font family, so once imported the font style can be used throughout the app. Google Fonts website has a wide variety of font families that can be downloaded and used in an app. The steps for downloading the file are as follows: 

• Step 1: Open Google Fonts and search for a font family in the search bar (here “Pacifico”).
• Step 2: Select the “Pacifico” font file.
• Step 3: To download, click the “Download Family” button.

Import Font Files: To use the downloaded font family, we need to import the font file into the root of the Flutter app. The steps for importing the font file in Android Studio are as follows: 

• Step 1: Click the “Project” button in the top left corner of Android Studio.
• Step 2: Right-click on the project name, here “gfg_custom_fonts” and select New + Directory.
• Step 3: Name the directory as “fonts“.
• Step 4: Open file manager and go to downloads. Extract and open the “Pacifico” zip file.
• Step 5: Move the “Pacifico Regular” file into this directory. After moving, the font directory contains a file named “Pacifico-Regular.ttf”.

Declare Font: Now after importing the font file, it’s a necessity to tell Flutter where to fetch the font file from. So, it’s a need to declare the font in a specific file named “pubspec.yaml” file. Indentation plays a major role in this file, where double-space is used to indent the code. The steps to declare the font file is as follows: 

• Step 1: Click the “Project” button and click on the project name, here “gfg_custom_fonts”.
• Step 2:  In the list, there is a file called “pubspec.yaml” file. Click this file.
• Step 3: Paste the below code in the pubspec.yaml file. Be aware of the indentations.
• Step 4: Press the “Pub get” button in the top right corner of the file.

Add Font Family: Now this font family can be used in styling the text widget in the app wherever needed. Not only one, but multiple families can be downloaded in the above-mentioned steps. 

Note: The name mentioned in the “family:” of the “pubspec.yaml” file should be unique for different font families. In order to use this font, the font family property of the text widget is used in the .dart file. 

The syntax for it is as follows: 

Text('text',
             style: TextStyle(
               fontFamily: 'family_name',
             ),
           ),

Complete Source Code: The final code after customizing the text style is as follows:

Output: 

Flutter is no doubt one of the best cross-platform mobile application development frameworks available in the present context. The ability to create pixel-perfect UI designs using a simple combination of widget structure has made Flutter a popular choice among mobile app developers. The widget integration along with logical coding through dart programming language can make the app user interface as well as user experience sublime. When it comes to the user interface, most of the area on the screen is covered with text. Text elements are used as a means of communication between the app and its end users. Hence, textual elements in an app display are the core element that impacts the overall UI/UX. Typographical elements influence the overall perspective of the user towards the app. Therefore, the typographical elements must be properly placed with correct parameters to make the UI look appealing and readable for the end-users. The font design, size, and weight, each parameter must be considered to amplify the overall user experience in any mobile application.

In this tutorial, we are going to learn how to add the custom font to our Flutter app. The integration will work for both Android as well as iOS platforms. The steps are simple and easy to understand. We are going to make use of Google Fonts to download the required fonts which we are going to integrate into our project. Google Fonts repository provides a wide variety of uniquely designed font packages. The idea is to download some of the most uniquely designed fonts and add them to the Flutter project. Then, we are going to register the downloaded custom fonts to the Flutter app ecosystem and then use them in our template.

Let’s get started!

Step 1: Create a new Flutter project

First, we need to create a new Flutter project. For that, make sure that the Flutter SDK and other flutter app development related requirements are properly installed. If everything is properly set up, then in order to create a project, we can simply run the following command in the desired local directory:

After the project has been set up, we can navigate inside the project directory and execute the following command in the terminal to run the project in either an available emulator or an actual device:

After a successful build, we will get the following result on the emulator screen:

Step 2: Download the Custom Fonts

Since we are going to install custom fonts to our Flutter project, we need to get those fonts first. We can simply download the different font design files from Google Fonts. Google Fonts provides a wide selection of font design as shown in the screenshot below:

To download the font files, we simply need to click on the font we want. Once, we select the font, the font detail window opens up where different styles, weights, sizes, and configuration information are provided. Then, we can simply click on the “+ Download family” button to download the required font files. The downloaded file will contain a full package of the font files with different font-weight specifications. Usually, the font files will be of extension (.tff). Now, we can use these font files in our Flutter project and use them.

For this project, we are going to download two distinct Font Families:

• Langer
• Dancing Script

We chose these font designs because they have a unique font design that we can easily identify and differentiate from other fonts. This will help us to easily distinguish between the default Flutter font and custom fonts.

The font file package will be downloaded in a compressed (zip) form. We need to unzip the folder to get the required font files.

Now, in our Flutter project, we need to create a ./assets folder in the root project folder. Inside the ./assets folders, we need to create another folder called ./fonts folder.

Next, we need to copy the required font files and paste them inside the ./assets/fonts folder of our Flutter project.

The folder structure is shown in the screenshot below:

Step 3: Register the Font

Now, we need to register the custom fonts to the Flutter ecosystem. For that, we need to mention them in the pubspec.yaml file with proper parameters. In the pubspec.yaml file, we have a flutter section. Inside the flutter section, there will the fonts section which has been commented out. With proper indentations, we have to register the fonts as shown in the code snippet below:

Here, we have a family parameter. The font family name mentioned in it can be used in the Flutter widgets. Then, we can point towards the designated custom font file using the assets parameter inside the fonts option.

Now, the fonts are ready to be used inside the Flutter project.

Step 4: Use the Font in Flutter template

In main.js, we have the default MyHomePage stateful widget. In the widget class, we can filter out the unnecessary default template widgets and add our own widgets with text style specifications. The overall code is provided in the code snippet below:

Here, we have used the Text widget inside the Column widget to display the text with different custom font families. Three Text widgets are added to show the normal font text, Dancing Script text, and Langer font text so that they can be easily distinguished.

Now, we can rebuild the app by executing the following command:

Hence, we will get the following result on the app screen:

We can notice the different font family styles on the screen above. Hence, this proves that the custom fonts are properly registered to the Flutter ecosystem and we can use them anywhere inside the project.

Step 5: Adding Weight Parameters to Registered Fonts

Now, let’s move to a few advanced configurations for custom fonts. Some unique fonts do not really accommodate themselves with the font style properties. They possess their own unique styling and have a separate font file for them. Here, we are going to take an example of the Bold font-weight of the Dancing Script font we used before. We are going to integrate the custom bold font of the Dancing Script in the Flutter ecosystem as well.

For that, we need to first copy the bold font-weight file from downloaded Dancing Script font files and paste it in ./assets/fonts as shown in the screenshot below:

Now, we need to register the bold font file under the same DancingScript font family as shown in the code snippet below:

You can also learn about the use of fabulous custom font design that suits the theme of the app by looking into some state of the art Flutter template available in the market.

Here, we have assigned the weight parameter to the second asset option. This weight parameter will help us specify the bold Dancing Script font file. Now, using the fontWeight property in the font with the value of 700 will directly point to this custom file. This will let us render out the actual bold style Dancing Script on the app screen.

Now, we can test it out by defining the fontWeight property for the Text widget containing DancingScript font-family as shown in the code snippet below:

Hence, we will get the result as shown in the code snippet below:

Here, we can notice the regular style and bold style of the Dancing Script font.

Likewise, we can also assign other parameters such as the style with specific file types of custom fonts. The ability to assign multiple font styles of a single font family using different parameters such as weight and style will enable us to display the true nature of uniquely customized Fonts. It provides us extra power over the overall usage of custom fonts in the Flutter ecosystem.

Conclusion

Hope that the steps were easy to understand. Actually, the overall integration process was simple and quick. While adding a custom font to the Flutter app, we should make sure that the font design matches the theme of the overall app. We should consider the size and weight of the font as well. We can even register the extra parameters such as font-weight to the project while registering the font in pubspec.yaml file. Choosing the right font design will definitely have a huge impact on any mobile application. The steps we learned from this tutorial will definitely help you boost the beauty of the app interface by means of different custom fonts.

In this example, we are going to show the way to change style of font inside text widget such as font-weight, font size, color, bold, italic, underline properties of font inside Text Widget in Flutter. See the example below for more details:

Text( 
  "Lorem Ipsum is simply dummy text.",
  style: TextStyle( 
      fontSize: 18,
      height: 2, //line height 200%, 1= 100%, were 0.9 = 90% of actual line height
      color: Colors.redAccent, //font color
      backgroundColor: Colors.black12, //background color
      letterSpacing: 5, //letter spacing
      decoration: TextDecoration.underline, //make underline
      decorationStyle: TextDecorationStyle.double, //double underline
      decorationColor: Colors.brown, //text decoration 'underline' color
      decorationThickness: 1.5, //decoration 'underline' thickness
      fontStyle: FontStyle.italic
  ),
)

Text( 
  "hello world",
  style: Theme.of(context).textTheme.headline1, // like <h1> in HTML
)

import 'package:flutter/material.dart';

void main(){
  runApp(MyApp());
}

class MyApp extends StatelessWidget{
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Home(),
    );
  }
}

class Home extends StatelessWidget{
  @override
  Widget build(BuildContext context) {
    return  Scaffold(
          appBar: AppBar( 
             title: Text("Text Style"),
             backgroundColor: Colors.deepOrangeAccent,
          ),
          body: Container(
            padding: EdgeInsets.all(20),
            child: Column( 
              crossAxisAlignment: CrossAxisAlignment.center,
              children: [
                
                Text( 
                  "Lorem Ipsum is simply dummy text.",
                  style: TextStyle( 
                     fontSize: 18,
                     height: 2, //line height 200%, 1= 100%, were 0.9 = 90% of actual line height
                     color: Colors.redAccent, //font color
                     backgroundColor: Colors.black12, //background color
                     letterSpacing: 5, //letter spacing
                     decoration: TextDecoration.underline, //make underline
                     decorationStyle: TextDecorationStyle.double, //double underline
                     decorationColor: Colors.brown, //text decoration 'underline' color
                     decorationThickness: 1.5, //decoration 'underline' thickness
                     fontStyle: FontStyle.italic
                  ),
                ),

                 Text( 
                  "Lorem Ipsum is simply dummy text of the printing and typesetting industry.",
                  style: TextStyle( 
                     fontSize: 38,
                     height: 0.9, //line height 90% of actual height
                     color: Colors.orangeAccent,
                     decoration: TextDecoration.lineThrough,
                  ),
                ),

                Text( 
                   "hello world",
                    style: Theme.of(context).textTheme.headline1, // like <h1> in HTML
                )
              ],
            ),
          )
       );
  }
}

In this way, you can make the font big, small, bold, italic, underline, double underline using TextStyle() on Text() widget in Flutter.