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Package detailsv3.1.3

sizer

Responsive UI solutions for Mobile, Web, and Desktop — making adaptability effortless.

AndroidiOSWebmacOSWindowsLinux
30-day downloads
72K
Likes
1.9K
Pub points
150

Install package

flutter pub add sizer

Package Overview

Package selection guidance compiled from public package information, community data, and project usage.

Sizer is a Flutter package that simplifies responsive UI design across mobile, web, and desktop platforms. It provides an easy way to create layouts that adapt seamlessly to different screen sizes and orientations by using logical units based on the device's screen dimensions. With Sizer, developers can define sizes relative to the screen width and height, ensuring consistent appearance regardless of device type or resolution. The package integrates smoothly into existing projects with minimal setup, making it ideal for building scalable and maintainable user interfaces.

Use cases

  • Building cross-platform responsive apps
  • Creating adaptive layouts for multiple screen sizes
  • Ensuring consistent UI scaling on mobile and desktop
  • Simplifying responsive design without complex media queries
  • Designing layouts that work on both small phones and large desktop screens

Key features

  • Automatic screen size adaptation
  • Support for all major platforms (Android, iOS, Web, macOS, Windows, Linux)
  • Easy-to-use scale-based sizing
  • Built-in orientation handling
  • Minimal boilerplate required

Suitable for

  • Developers targeting multiple platforms
  • Teams prioritizing UI consistency
  • Projects requiring rapid responsive layout implementation
  • Beginners learning responsive Flutter design
  • Apps needing dynamic scaling across diverse devices

Considerations

  • May require initial adjustment of existing hardcoded values
  • Best used with a consistent design system
  • Not ideal for highly custom or non-uniform scaling needs
  • Limited to size-based responsiveness, not layout structure changes
  • Requires understanding of logical pixel scaling principles

Original README

Original README snapshot from the linked source repository. Visit the repository for the latest content.

Sizer (Responsive UI solution for Mobile App,Web and Desktop)

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A Flutter package that simplifies responsive design by automatically adapting your app’s UI to any screen size — making responsiveness seamless and intuitive.

With Sizer

Without Sizer

Content

Installation ⬇️

Add sizer to pubspec.yaml

dependencies:
  sizer: ^3.1.3
How to use ⚙️
Import the Package
import 'package:sizer/sizer.dart';
Wrap MaterialApp with Sizer widget
Sizer( 
  builder: (context, orientation, screenType) {
    return MaterialApp(
      home: HomePage(),
    );
  },
);
Widget Size
Container(
  width: Adaptive.w(20),    // This will take 20% of the screen's width
  height: 30.5.h     // This will take 30.5% of the screen's height
)
Font size
Text(
  'Sizer', 
  style: TextStyle(fontSize: 15.dp), 
  // 15.sp can also be used instead of .dp
  // To know their differences, check #FAQ
)
Orientation

If your app needs to work seamlessly in both portrait and landscape orientations

Device.orientation == Orientation.portrait
  ? Container(   // Widget for Portrait
      width: 100.w,
      height: 20.5.h,
   )
  : Container(   // Widget for Landscape
      width: 100.w,
      height: 12.5.h,
   )
ScreenType

Same layout to look different in tablet and mobile, use the Device.screenType method:

Device.screenType == ScreenType.tablet
  ? Container(   // Widget for Tablet
      width: 100.w,
      height: 20.5.h,
   )
  : Container(   // Widget for Mobile
      width: 100.w,
      height: 12.5.h,
   )

*Device.ScreenType can not be Desktop unless maxTabletWidth is set

Guideline

Sizer
  • maxMobileWidth - Maximum width of a mobile device (If the device's width is larger than this, it will be categorized as a tablet) - Default value: 599
  • maxTabletWidth - Maximum width of a tablet device (If the device's width is larger than this, it will be categorized as a desktop) - Optional: enables Desktop ScreenType if enabled
Extensions
  • Adaptive.h() or .h - Calculated percentage of the device's height (40.h -> 40% of device's height)
  • Adaptive.w() or .w - Calculated percentage of the device's width (40.w -> 40% of device's width)
  • Adaptive.sp() or .sp - Calculated sp based on the device's pixel density and aspect ratio (See FAQ)
  • Adaptive.dp() or .dp - Calculated dp based on the device's pixel density (See FAQ)
*Note: Only use .sh and .sw if you want height and width to depend on the device's available height and width after applying SafeArea. Use .h and .w by default.
  • Adaptive.sh() or .sh - Calculated percentage of the remaining device's height after applying SafeArea
  • Adaptive.sw() or .sw - Calculated percentage of the remaining device's width after applying SafeArea

  • Device.boxConstraints - BoxConstraints of the device
  • Device.orientation - Screen Orientation of the device (portrait or landscape)
  • Device.screenType - Screen type of the device (mobile or tablet)
  • Device.aspectRatio - Aspect ratio of the device
  • Device.pixelRatio - Pixel density ratio of the device

  • Adaptive.cm() or .cm - The respective value in value in centimeters
  • Adaptive.mm() or .mm - The respective value in value in millimeters
  • Adaptive.Q() or .Q - The respective value in quarter-millimeters
  • Adaptive.inches() or .inches - The respective value in inches
  • Adaptive.pc() or .pc - The respective value in picas (1/6th of 1 inch)
  • Adaptive.pt() or .pt - The respective value in points (1/72th of 1 inch)
  • Adaptive.px() or .px - The respective value in pixels

Note

You need to import sizer package in order to access number.h, number.w, number.dp, and number.sp

Auto import in VSCode and Android Studio doesn't work for dart extension methods. Typing 10.h would not bring up auto import suggestion for this package

One workaround is to type Device so that the auto import suggestion would show up:

import 'package:sizer/sizer.dart';

FAQ

What is the difference between .sp and .dp?

.dp is supposedly calculated see below based on Material Design's dp calculation while.sp is calculated based on the device's pixel density and aspect ratio

Why is dp not calculated using the device's screen density?

Since there is no way to obtain a device's physical width in inches, we could not calculate for screen density. Material Design's screen density calculation involves a device's physical width in inches. As an alternative, dp is calculated using the device's pixel ratio.

Community Support

If you have any suggestions or issues, feel free to open an issue

If you would like to contribute, feel free to create a PR

Categories

Source repository

Projects using this package