Manager class for the widgets framework.

This class tracks which widgets need rebuilding, and handles other tasks that apply to widget trees as a whole, such as managing the inactive element list for the tree and triggering the "reassemble" command when necessary during debugging.

The main build owner is typically owned by the WidgetsBinding, and is driven from the operating system along with the rest of the build/layout/paint pipeline.

Additional build owners can be built to manage off-screen widget trees.

To assign a build owner to a tree, use the RootRenderObjectElement.assignOwner method on the root element of the widget tree.

Constructors

BuildOwner({VoidCallback onBuildScheduled })
Creates an object that manages widgets.

Properties

debugBuilding bool
Whether this widget tree is in the build phase. [...]
read-only
focusManager FocusManager
The object in charge of the focus tree. [...]
final
onBuildScheduled VoidCallback
Called on each build pass when the first buildable element is marked dirty.
read / write
hashCode int
The hash code for this object. [...]
read-only, inherited
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited

Methods

buildScope(Element context, [ VoidCallback callback ]) → void
Establishes a scope for updating the widget tree, and calls the given callback, if any. Then, builds all the elements that were marked as dirty using scheduleBuildFor, in depth order. [...]
finalizeTree() → void
Complete the element build pass by unmounting any elements that are no longer active. [...]
lockState(void callback()) → void
Establishes a scope in which calls to State.setState are forbidden, and calls the given callback. [...]
reassemble(Element root) → void
Cause the entire subtree rooted at the given Element to be entirely rebuilt. This is used by development tools when the application code has changed, to cause the widget tree to pick up any changed implementations. [...]
scheduleBuildFor(Element element) → void
Adds an element to the dirty elements list so that it will be rebuilt when WidgetsBinding.drawFrame calls buildScope.
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

Operators

operator ==(other) bool
The equality operator. [...]
inherited