MapLegend class Null safety

Shows legend for the bubbles or shapes.

Information provided in the legend helps to identify the data rendered in the map shapes or bubbles.

Defaults to null.

By default, legend will not be shown.

Legend for shape

Set MapLegend.source to MapElement.shape to show legend for shapes.

If MapShapeSource.shapeColorMappers is not null, then MapColorMapper.color and MapColorMapper.text will be used for the legend item's icon and the legend item's text respectively.

If MapShapeSource.shapeColorMappers is null, the color returned in the MapShapeSource.shapeColorValueMapper will be applied to the legend item's icon and the legend item's text will be taken from the MapShapeSource.shapeDataField.

In a rare case, if both the MapShapeSource.shapeColorMappers and the MapShapeSource.shapeColorValueMapper properties are null, the legend item's text will be taken from the MapShapeSource.shapeDataField property and the legend item's icon will have the default color.

Legend for bubbles

Set MapLegend.source to MapElement.bubble to show legend for bubbles.

If MapShapeSource.bubbleColorMappers is not null, then MapColorMapper.color and MapColorMapper.text will be used for the legend item's icon and the legend item's text respectively.

If MapShapeSource.bubbleColorMappers is null, the color returned in the MapShapeSource.bubbleColorValueMapper will be applied to the legend item's icon and the legend item's text will be taken from the MapShapeSource.shapeDataField.

If both the MapShapeSource.bubbleColorMappers and the MapShapeSource.bubbleColorValueMapper properties are null, the legend item's text will be taken from the MapShapeSource.shapeDataField property and the legend item's icon will have the default color.

The below code snippet represents how to setting default legend to the shape.

late List<DataModel> _data;
late MapShapeSource _mapSource;

 @override
 void initState() {
   super.initState();

   _data = <DataModel>[
     DataModel('India', 280, "Low"),
     DataModel('United States of America', 190, "High"),
     DataModel('Pakistan', 37, "Low"),
   ];

   _mapSource = MapShapeSource.asset(
     "assets/world_map.json",
     shapeDataField: "name",
     dataCount: _data.length,
     primaryValueMapper: (int index) {
       return _data[index].country;
     },
     shapeColorValueMapper: (int index) {
       return _data[index].storage;
     },
     shapeColorMappers: [
       MapColorMapper(value: "Low", color: Colors.red),
       MapColorMapper(value: "High", color: Colors.green)
     ],
   );
 }

 @override
 Widget build(BuildContext context) {
   return Scaffold(
     appBar: AppBar(
       title: Text('Default legend'),
     ),
     body: Center(
       child: SfMaps(
         layers: [
           MapShapeLayer(
             source: _mapSource,
             legend: MapLegend(MapElement.shape),
           )
         ],
       ),
     ),
   );
 }

class DataModel {
  const DataModel(this.country, this.count, this.storage);

  final String country;
  final double count;
  final String storage;
}

The below code snippet represents how to setting bar legend to the shape.

late List<DataModel> _data;
late MapShapeSource _mapSource;

 @override
 void initState() {
   super.initState();

   _data = <DataModel>[
     DataModel('India', 280, "Low"),
     DataModel('United States of America', 190, "High"),
     DataModel('Pakistan', 37, "Low"),
   ];

   _mapSource = MapShapeSource.asset(
     "assets/world_map.json",
     shapeDataField: "name",
     dataCount: _data.length,
     primaryValueMapper: (int index) {
       return _data[index].country;
     },
     shapeColorValueMapper: (int index) {
       return _data[index].storage;
     },
     shapeColorMappers: [
       MapColorMapper(value: "Low", color: Colors.red),
       MapColorMapper(value: "High", color: Colors.green)
     ],
   );
 }

 @override
 Widget build(BuildContext context) {
   return Scaffold(
     appBar: AppBar(
       title: Text('Bar legend'),
     ),
     body: Center(
       child: SfMaps(
         layers: [
           MapShapeLayer(
             source: _mapSource,
             legend: MapLegend.bar(MapElement.shape),
           )
         ],
       ),
     ),
   );
 }

class DataModel {
  const DataModel(this.country, this.count, this.storage);

  final String country;
  final double count;
  final String storage;
}
Inheritance
Annotations

Constructors

MapLegend(MapElement source, {Widget? title, MapLegendPosition position = MapLegendPosition.top, Offset? offset, MapLegendOverflowMode overflowMode = MapLegendOverflowMode.wrap, Axis? direction, EdgeInsetsGeometry? padding = const EdgeInsets.all(10.0), double spacing = 10.0, MapIconType iconType = MapIconType.circle, Size iconSize = const Size(8.0, 8.0), TextStyle? textStyle, bool enableToggleInteraction = false, Color? toggledItemColor, Color? toggledItemStrokeColor, double toggledItemStrokeWidth = 1.0, double toggledItemOpacity = 0.5})
Creates a legend with different styles like circle, rectangle, triangle and square for the bubbles or shapes. [...]
const
MapLegend.bar(MapElement source, {Widget? title, MapLegendOverflowMode overflowMode = MapLegendOverflowMode.scroll, EdgeInsetsGeometry? padding = const EdgeInsets.all(10.0), MapLegendPosition position = MapLegendPosition.top, Offset? offset, double spacing = 2.0, Size? segmentSize, TextStyle? textStyle, Axis? direction, MapLegendLabelsPlacement? labelsPlacement, MapLegendEdgeLabelsPlacement edgeLabelsPlacement = MapLegendEdgeLabelsPlacement.inside, MapLabelOverflow labelOverflow = MapLabelOverflow.visible, MapLegendPaintingStyle segmentPaintingStyle = MapLegendPaintingStyle.solid, bool showPointerOnHover = false, MapLegendPointerBuilder? pointerBuilder, Color? pointerColor, Size pointerSize = const Size(16, 12)})
Creates a bar type legend for the bubbles or shapes. [...]
const

Properties

direction Axis?
Arranges the legend items in either horizontal or vertical direction. [...]
final
edgeLabelsPlacement MapLegendEdgeLabelsPlacement
Place the edge labels either inside or outside of the bar legend. [...]
final
enableToggleInteraction bool
Enables the toggle interaction for the legend. [...]
final
hashCode int
The hash code for this object. [...]
read-only, override
iconSize Size
Customizes the size of the icon. [...]
final
iconType MapIconType
Specifies the shape of the legend icon. [...]
final
labelOverflow MapLabelOverflow
Trims or removes the legend text when it is overflowed from the bar legend. Defaults to MapLabelOverflow.hide. [...]
final
labelsPlacement MapLegendLabelsPlacement?
Place the labels either between the segments or on the segments. [...]
final
offset Offset?
Places the legend in custom position. [...]
final
overflowMode MapLegendOverflowMode
Wraps or scrolls the legend items when it overflows. [...]
final
padding EdgeInsetsGeometry?
Sets the padding around the legend. [...]
final
pointerBuilder MapLegendPointerBuilder?
Returns a widget for the given value. [...]
final
pointerColor Color?
Customizes the color of the pointer.
final
pointerSize Size
Customizes the size of the pointer.
final
position MapLegendPosition
Positions the legend in the different directions. [...]
final
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited
segmentPaintingStyle MapLegendPaintingStyle
Applies gradient or solid color for the bar segments. [...]
final
segmentSize Size?
Customizes the size of the bar segments. [...]
final
showPointerOnHover bool
Specifies whether the pointer should be shown while hovering on the MapLegend segments.
final
source MapElement
Shows legend for the bubbles or shapes. [...]
final
spacing double
Specifies the space between the each legend items. [...]
final
textStyle TextStyle?
Customizes the legend item's text style. [...]
final
title Widget?
Sets a title for the legend. [...]
final
toggledItemColor Color?
Fills the toggled legend item's icon and the respective shape or bubble by this color. [...]
final
toggledItemOpacity double
Sets the toggled legend item's text opacity. [...]
final
toggledItemStrokeColor Color?
Stroke color for the toggled legend item's respective shape or bubble. [...]
final
toggledItemStrokeWidth double
Stroke width for the toggled legend item's respective shape or bubble. [...]
final

Methods

copyWith({Axis? direction, EdgeInsetsGeometry? padding, MapLegendPosition? position, Widget? title, Offset? offset, double? spacing, MapIconType? iconType, TextStyle? textStyle, Size? iconSize, Size? segmentSize, MapLegendOverflowMode? overflowMode, bool? enableToggleInteraction, Color? toggledItemColor, Color? toggledItemStrokeColor, double? toggledItemStrokeWidth, double? toggledItemOpacity, MapElement? source, MapLegendLabelsPlacement? labelsPlacement, MapLegendEdgeLabelsPlacement? edgeLabelsPlacement, MapLabelOverflow? labelOverflow, MapLegendPaintingStyle? segmentPaintingStyle, bool? showPointerOnHover, MapLegendPointerBuilder? pointerBuilder, Color? pointerColor, Size? pointerSize}) MapLegend
Creates a copy of this class but with the given fields replaced with the new values.
debugDescribeChildren() List<DiagnosticsNode>
Returns a list of DiagnosticsNode objects describing this node's children. [...]
@protected, inherited
debugFillProperties(DiagnosticPropertiesBuilder properties) → void
Add additional properties associated with the node. [...]
override
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent 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 brief description of this object, usually just the runtimeType and the hashCode. [...]
inherited

Operators

operator ==(Object other) bool
The equality operator. [...]
override