A material design app bar.
An app bar consists of a toolbar and potentially other widgets, such as a TabBar and a FlexibleSpaceBar. App bars typically expose one or more common actions with IconButtons which are optionally followed by a PopupMenuButton for less common operations.
App bars are most commonly used in the appBar property, which places the app bar at the top of the app.
The AppBar displays the toolbar widgets, leading, title, and actions, above the bottom (if any). If a flexibleSpace widget is specified then it is stacked behind the toolbar and the bottom widget.
The Scaffold typically creates the app bar with an initial height equal to expandedHeight. If the appBarBehavior is set then the AppBar's collapsedHeight and bottomHeight define how small the app bar will become when the application is scrolled.
See also:
- Scaffold, which displays the AppBar in its appBar slot.
- TabBar, which is typically placed in the bottom slot of the AppBar if the screen has multiple pages arranged in tabs.
- IconButton, which is used with actions to show buttons on the app bar.
- PopupMenuButton, to show a popup menu on the app bar, via actions.
- FlexibleSpaceBar, which is used with flexibleSpace when the app bar can expand and collapse.
- material.google.com/layout/structure.html#structure-toolbars
- Inheritance
- Object
- Widget
- StatelessWidget
- AppBar
Static Methods
-
getExpandedHeightFor(
BuildContext context) → double -
Returns the expandedHeight of the AppBar nearest to the given BuildContext.
Constructors
- AppBar({Key key, Widget leading, Widget title, List<Widget> actions, Widget flexibleSpace, AppBarBottomWidget bottom, int elevation: 4, Color backgroundColor, Brightness brightness, IconThemeData iconTheme, TextTheme textTheme, EdgeInsets padding: EdgeInsets.zero, bool centerTitle, Object heroTag, double expandedHeight, double collapsedHeight })
-
Creates a material design app bar.
Properties
- actions → List<Widget>
-
Widgets to display after the title widget.
read-only - backgroundColor → Color
-
The color to use for the app bar's material. Typically this should be set along with brightness, iconTheme, textTheme.
read-only - bottom → AppBarBottomWidget
-
This widget appears across the bottom of the appbar.
read-only - bottomHeight → double
-
The height of the bottom widget. The
Scaffolduses this value to control the size of the app bar when its appBarBehavior isAppBarBehavior.scrollorAppBarBehavior.under.read-only - brightness → Brightness
-
The brightness of the app bar's material. Typically this is set along with backgroundColor, iconTheme, textTheme.
read-only - centerTitle → bool
-
Whether the title should be centered.
read-only - collapsedHeight → double
-
By default, the height of the toolbar and the bottom widget (if any). If the height of the app bar is constrained to be less than this value then the toolbar and bottom widget are scrolled upwards, out of view.
read-only - elevation → int
-
The z-coordinate at which to place this app bar.
read-only - expandedHeight → double
-
By default, the total height of the toolbar and the bottom widget (if any). The
Scaffoldgives its app bar this height initially. If aflexibleSpacewidget is specified this height should be big enough to accommodate whatever that widget contains.read-only - flexibleSpace → Widget
-
This widget is stacked behind the toolbar and the tabbar and it is not inset by the specified padding. It's height will be the same as the the app bar's overall height.
read-only - heroTag → Object
-
The tag to apply to the app bar's Hero widget.
read-only - iconTheme → IconThemeData
-
The color, opacity, and size to use for app bar icons. Typically this is set along with backgroundColor, brightness, textTheme.
read-only - leading → Widget
-
A widget to display before the title.
read-only - padding → EdgeInsets
-
The amount of space by which to inset the contents of the app bar. The Scaffold increases
padding.topby the height of the system status bar so that the toolbar appears below the status bar.read-only - textTheme → TextTheme
-
The typographic styles to use for text in the app bar. Typically this is set along with
brightnessbackgroundColor, iconTheme.read-only - title → Widget
-
The primary widget displayed in the appbar.
read-only - hashCode → int
-
Get a hash code for this object.
read-only, inherited - key → Key
-
Controls how one widget replaces another widget in the tree.
read-only, inherited - runtimeType → Type
-
A representation of the runtime type of the object.
read-only, inherited
Operators
-
operator ==(
other) → bool -
The equality operator.
inherited
Methods
-
build(
BuildContext context) → Widget -
Describes the part of the user interface represented by this widget.
-
copyWith(
{Key key, Widget leading, Widget title, List<Widget> actions, Widget flexibleSpace, AppBarBottomWidget bottom, int elevation, Color backgroundColor, Brightness brightness, TextTheme textTheme, EdgeInsets padding, Object heroTag, double expandedHeight, double collapsedHeight }) → AppBar -
Creates a copy of this app bar but with the given fields replaced with the new values.
-
createElement(
) → StatelessElement -
Creates a StatelessElement to manage this widget's location in the tree.
inherited -
debugFillDescription(
List<String> description) → void -
Add additional information to the given description for use by toString.
inherited -
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a non-existent method or property is accessed.
inherited -
toString(
) → String -
Returns a string representation of this object.
inherited -
toStringShort(
) → String -
A short, textual description of this widget.
inherited