How to Size Widget to Percentage of Screen Height/Width in Flutter
Introduction
In Flutter, sizing a widget to a percentage of the screen height or width can be a bit tricky, but it’s a common requirement in many mobile app designs. In this article, we will explore how to achieve this using various methods.
Understanding Screen Size
Before we dive into sizing widgets, it’s essential to understand how to get the screen size in Flutter. We can use the `MediaQuery` class to get the screen height and width.
Sizing Widgets
To size a widget to a percentage of the screen height or width, we can use the `SizedBox` widget or the `Container` widget with a specified height or width. We can calculate the height or width by multiplying the screen height or width with the desired percentage.
Example Code
“`dart
import ‘package:flutter/material.dart’;
class SizeWidgetExample extends StatelessWidget {
@override
Widget build(BuildContext context) {
final screenWidth = MediaQuery.of(context).size.width;
final screenHeight = MediaQuery.of(context).size.height;
return Container(
child: Column(
children: [
// Sizing a widget to 30% of the screen height
SizedBox(
height: screenHeight * 0.3,
child: Container(
color: Colors.blue,
),
),
// Sizing a widget to 50% of the screen width
Container(
width: screenWidth * 0.5,
height: 100,
color: Colors.red,
),
],
),
);
}
}
“`
Using LayoutBuilder
We can also use the `LayoutBuilder` widget to size a widget to a percentage of the screen height or width. This method is useful when we want to size a widget based on the available space.
Example Code
“`dart
import ‘package:flutter/material.dart’;
class SizeWidgetExample extends StatelessWidget {
@override
Widget build(BuildContext context) {
return LayoutBuilder(
builder: (context, constraints) {
return Container(
child: Column(
children: [
// Sizing a widget to 30% of the available height
SizedBox(
height: constraints.maxHeight * 0.3,
child: Container(
color: Colors.blue,
),
),
// Sizing a widget to 50% of the available width
Container(
width: constraints.maxWidth * 0.5,
height: 100,
color: Colors.red,
),
],
),
);
},
);
}
}
“`
Conclusion
Sizing a widget to a percentage of the screen height or width in Flutter can be achieved using various methods. By using the `MediaQuery` class, `SizedBox` widget, or `LayoutBuilder` widget, we can easily size our widgets to meet our design requirements.
FAQ
1. How do I get the screen size in Flutter?
We can use the `MediaQuery` class to get the screen size in Flutter.
2. Can I size a widget to a percentage of the screen height or width?
Yes, we can size a widget to a percentage of the screen height or width using the `SizedBox` widget or the `Container` widget with a specified height or width.
3. What is the difference between `MediaQuery` and `LayoutBuilder`?
`MediaQuery` gives us the total screen size, while `LayoutBuilder` gives us the available space.
4. How do I size a widget to a percentage of the available space?
We can use the `LayoutBuilder` widget to size a widget to a percentage of the available space.
5. Can I use `SizedBox` widget to size a widget to a percentage of the screen height or width?
Yes, we can use the `SizedBox` widget to size a widget to a percentage of the screen height or width.
