OffsetDetector class

OffsetDetector is a widget that encapsulates OffsetChangeObserver.

When the screen position of child changes, such as horizontal and vertical screen switching, soft keyboard display and hiding, etc., onChanged will be called.

This snippet will print size, offset, rootPadding when the widget is offset.

Padding(
  padding: EdgeInsets.fromLTRB(8, 0, 8, 3),
  child: OffsetDetector(
      onChanged: (Size size, EdgeInsets offset, EdgeInsets rootPadding) {
          print("The widget size: ${size.width}, ${size.height}");
          print(
           "The offset to edge of root(ltrb): ${offset.left}, ${offset.top}, ${offset.right}, ${offset.bottom}");
          print(
           "the root padding: ${rootPadding.left}, ${rootPadding.top}, ${rootPadding.right}, ${rootPadding.bottom}");
      },
      child: TextField(
        style: textFieldStyle,
      )),
)

Inheritance

• Object
• DiagnosticableTree
• Widget
• StatefulWidget
• OffsetDetector

Constructors

OffsetDetector({Key? key, required OffsetChangedCallback onChanged, required Widget child, OffsetDetectorController? controller, KeyboardStateCallback? onKeyboard})

Create a widget whose offset state needs to be observed.

Properties

child → Widget

child is the widget that needs to be observed

final

controller → OffsetDetectorController

Controller of OffsetDetector

final

hashCode → int

The hash code for this object.

no setter, inherited

key → Key?

Controls how one widget replaces another widget in the tree.

final, inherited

onChanged → OffsetChangedCallback

Callback method when offset occurs

final

onKeyboard → KeyboardStateCallback?

Callback method when offset occurs

final

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

createElement() → StatefulElement

Creates a StatefulElement to manage this widget's location in the tree.

inherited

createState() → State<StatefulWidget>

Creates the mutable state for this widget at a given location in the tree.

override

debugDescribeChildren() → List<DiagnosticsNode>

Returns a list of DiagnosticsNode objects describing this node's children.

inherited

debugFillProperties(DiagnosticPropertiesBuilder properties) → void

Add additional properties associated with the node.

inherited

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toDiagnosticsNode({String? name, DiagnosticsTreeStyle? style}) → DiagnosticsNode

Returns a debug representation of the object that is used by debugging tools and by DiagnosticsNode.toStringDeep.

inherited

toString({DiagnosticLevel minLevel = DiagnosticLevel.info}) → String

A string representation of this object.

inherited

toStringDeep({String prefixLineOne = '', String? prefixOtherLines, DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String

Returns a string representation of this node and its descendants.

inherited

toStringShallow({String joiner = ', ', DiagnosticLevel minLevel = DiagnosticLevel.debug}) → String

Returns a one-line detailed description of the object.

inherited

toStringShort() → String

A short, textual description of this widget.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited