How to get AppBar height in Flutter

Question

How can I get the height of an AppBar in Flutter?
I am using the MarialApp Widget ('package:flutter/material.dart').

I have the height of my Context and would like to deduct the height of the appbar.

final double height = MediaQuery.of(context).size.height;

Answer 1

This is not an ideal way, I think, but it will work.

Firstly declare the AppBar widget that you will use in your Scaffold.

Widget demoPage() {
  AppBar appBar = AppBar(
    title: Text('Demo'),
  );
  return Scaffold(
    appBar: appBar,
    body: /*
    page body
    */,
  );
}

Now you can get the height of your appBar using its preferredSized:

double height = appBar.preferredSize.height;

You can use this height to reduce from the screen height.

final double height = MediaQuery.of(context).size.height;

Answer 2

There is no need to store the AppBar instance, or to create a dummy one to get the height. Also, AppBar.preferredSize will always return the same value of 56.0, which is the standard of Material Design, and this value will not be always usable for some cases (it lacks the height of the status bar for example).

Since an AppBar is surely used with a Scaffold, IMHO, the smarter way to get the real AppBar height (the distance between the top of the device and the top of the Scaffold body) is to use:

double height = Scaffold.of(context).appBarMaxHeight;

With this, the computed height will include (independently of the platform):

• The status bar height
• The app bar height
• The bottom app bar widget height if any (ex. TabBar)

Hope this will help!

Answer 3

you can use this :

var height = AppBar().preferredSize.height;

this way is very sample and easy

Answer 4

There is a constant for the normal toolbar height: kToolbarHeight

Answer 5

Just watch in AppBar

MediaQuery.of(context).padding.top + kToolbarHeight

Answer 6

Get body height:

MediaQuery.of(context).size.height - (MediaQuery.of(context).padding.top + kToolbarHeight)

I hope, this solution will also help you. Thanks to ask this question.

Answer 7

AppBar has a fixed height of 56.

You should create your own appbar implementing PreferredSizeWidget

class TestAppBar extends StatelessWidget implements PreferredSizeWidget {
  @override
  Widget build(BuildContext context) {
    return AppBar(
      title: Text('TEST'),
      centerTitle: true,
    );
  }

  @override
  Size get preferredSize => Size.fromHeight(34);
}

Answer 8

kToolbarHeight is default Appbar's height

kBottomNavigationBarHeight is default bottom navigation height

this will perfectly center align your progress indicator

    SizedBox(
            width: MediaQuery.of(context).size.width,
            height: MediaQuery.of(context).size.height - (kToolbarHeight + kBottomNavigationBarHeight),
            child: const Center(child: CircularProgressIndicator()));

Answer 9

You can get height of AppBar by using:

double height = appBar.preferredSize.height;

Make sure you have declared AppBar widget.

Answer 10

AppBer hight increase . You use PreferredSize and set height

appBar: PreferredSize(
            preferredSize: Size.fromHeight(70),
            child: AppBar(
              child : Text(" ");
            ),
          ),

Answer 11

Within the Widget build you need to get the height and width of a standard AppBar, then use the values to declare a Size object and then input the height and width as arguments.

You can do so as follows for a custom AppBar that I have called MyAppBar()

Widget build(BuildContext context) {
//get the height and width of a standard appBar to use with custom Appbar

var appBarWidth = MediaQuery.of(context).size.width;
var appBarHeight = AppBar().preferredSize.height;

return Scaffold(
  appBar: PreferredSize(
    preferredSize: Size(appBarWidth, appBarHeight),
    child: MyAppBar(),
  ),

Answer 12

You can use this:

  @override
  final Size preferredSize; // default is 56.0

  WidgetAppBar({@required this.appBarTitle, @required this.appBarColor, Key key}) : preferredSize = Size.fromHeight(40), super(key: key);

Answer 13

This will give height of appbar or statusbar

var height = MediaQuery.of(context).padding.top;

However, this will work only in mobile devices, other devices don't have status bar

Answer 14

Use preferred size of appBar to get height of AppBar.

var appBarHeight = AppBar().preferredSize.height;

Answer 15

Value of AppBar height is 56.0 but

You can get with code

double height = AppBar().preferredSize.height;

Answer 16

Use preferred size

//defined as
Size preferredSize

preferred size is a size whose height is the sum of kToolbarHeight and the bottom widget's preferred height.

Scaffold uses this size to set its app bar's height.

It is defined like below in app bar class which implement PreferredSizeWidget

 preferredSize = new Size.fromHeight(kToolbarHeight + (bottom?.preferredSize?.height ?? 0.0))

a link for example ...

https://github.com/flutter/flutter/blob/master/packages/flutter/lib/src/material/app_bar.dart