How to Get the Height of a Widget in Flutter?

To get the height of a widget in Flutter, you can use the LayoutBuilder widget to obtain the constraints of the parent container and then get the height from those constraints.

How to use it?

You can simply use this widget anywhere in your project as you needed that.

LayoutBuilder(
           builder: (BuildContext context, BoxConstraints constraints) {
             double height = constraints.maxHeight;
             print("The height of the container is $height");
             return Text("The height of the container is $height");
           },
         ),

Step By Step Implementation

Step 1: Create a New Project in Android Studio

To set up Flutter Development on Android Studio please refer to Android Studio Setup for Flutter Development, and then create a new project in Android Studio please refer to Creating a Simple Application in Flutter.

Step 2: Import the material package

A material package gives us the essential functions and Parameters, Now call the runApp method that needs an Application in the main function.

import 'package:flutter/material.dart';

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

In the above code, runApp method calls the class RunMyApp, Now we have to create it.

Step 3: Creating Stateless Widget

Now we have to make a stateless widget because our application does not go to change its state and then return the MaterialApp widget which allows us the set the title and theme and many more of the application.

Shortcut: For creating a stateless or Stateful widget, you can create a stateless or stateful widget by just typing three alphabets ‘stl’ and you can see a stateless widget and then hit enter.

class RunMyApp extends StatelessWidget {
 const RunMyApp({super.key});
 
@override
Widget build(BuildContext context) {
   return MaterialApp();
  }
}

Step 4: Working with Scaffold Widget

Give the home property and there can be a scaffold widget with AppBar and body property. AppBar allows us to give the title of AppBar, color, leading, and trailing icon.

home: Scaffold(
appBar: AppBar(
   title: Text('Appbar'),
),
body: 
),

Step 5: In the body, you can use the LayoutBuilder to get the height of the widget.

LayoutBuilder(
          builder: (BuildContext context, BoxConstraints constraints) {
            double height = constraints.maxHeight;
            print("The height of the container is $height");
            return Text("The height of the container is $height");
          },
        ),

Code: 

Dart

import 'package:flutter/material.dart';

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

class RunMyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      theme: ThemeData(primarySwatch: Colors.green),
      home: Scaffold(
        appBar: AppBar(
          title: Text('Appbar'),
        ),
        body: Container(
          child: Center(
            child: LayoutBuilder(
              builder: (BuildContext context, BoxConstraints constraints) {
                double height = constraints.maxHeight;

                return Text("The height of the container is $height");
              },
            ),
          ),
        ),
      ),
    );
  }
}

Output: