KChartWidget class

An interactive candlestick chart.

Pass the candles positionally along with a ChartColors. Run DataUtil.calculate over the list first so the indicator fields are populated, otherwise the overlays and sub-charts have nothing to draw.

The chart supports pinch-to-zoom, fling scrolling, a long-press crosshair with an info dialog, and — when isTrendLine is set and a currentDrawingTool is selected — placing trend, horizontal and vertical lines that the user can then select, drag, restyle and delete. The onAdd* and onRemove* callbacks let you persist those.

DataUtil.calculate(candles);

KChartWidget(
  candles,
  ChartColors(),
  isTrendLine: false,
  watermarkAssetPath: 'assets/logo.svg',
  timeFrame: const Duration(minutes: 15),
  indicators: [MaIndicator(period: 20), MacdIndicator()],
);
Inheritance

Constructors

KChartWidget(List<KLineEntity>? candles, ChartColors chartColors, {required bool isTrendLine, required String watermarkAssetPath, required Duration timeFrame, double xFrontPadding = 80, List<SignalEntity> signals = const <SignalEntity>[], List<VerticalLine> verticalLines = const <VerticalLine>[], List<HorizontalLine> horizontalLines = const <HorizontalLine>[], List<TrendLine> trendLines = const <TrendLine>[], List<Indicator> indicators = const <Indicator>[], DrawingTool currentDrawingTool = DrawingTool.none, ValueChanged<TrendLine>? onAddTrendLine, ValueChanged<HorizontalLine>? onAddHorizontalLine, ValueChanged<VerticalLine>? onAddVerticalLine, ValueChanged<TrendLine>? onRemoveTrendLine, ValueChanged<HorizontalLine>? onRemoveHorizontalLine, ValueChanged<VerticalLine>? onRemoveVerticalLine, bool volHidden = false, bool isLine = false, bool isTapShowInfoDialog = false, bool hideGrid = false, bool showNowPrice = true, bool showInfoDialog = true, bool materialInfoDialog = true, ChartStyle chartStyle = const ChartStyle(), DrawingStyle drawingStyle = const DrawingStyle(), ChartTranslations chartTranslations = const ChartTranslations(), List<String> timeFormat = TimeFormat.YEAR_MONTH_DAY, Widget? infoDialogBuilder(BuildContext, KLineEntity?, KLineEntity?)?, String dateFormatter(KLineEntity, bool)?, ValueChanged<bool>? onLoadMore, int fixedLength = 2, int flingTime = 600, double flingRatio = 0.5, Curve flingCurve = Curves.decelerate, ValueChanged<bool>? isOnDrag, VerticalTextAlignment verticalTextAlignment = VerticalTextAlignment.left, double? mBaseHeight, double infoDialogWidth = 132, double infoDialogMaxWidth = 240, Key? key})
Creates a candlestick chart over candles, coloured by chartColors.
const

Properties

candles → List<KLineEntity>?
The candles to draw, oldest first. Null renders a loading indicator.
final
chartColors → ChartColors
Every colour the chart paints with.
final
chartStyle → ChartStyle
Geometry: paddings, stroke widths and text sizes.
final
chartTranslations → ChartTranslations
Labels used by the info dialog and on-chart text.
final
currentDrawingTool → DrawingTool
The active drawing mode; see DrawingTool.
final
dateFormatter → String Function(KLineEntity, bool)?
Overrides axis date formatting; the flag marks the long form.
final
drawingStyle → DrawingStyle
How the drawing tools look and what their editor offers.
final
fixedLength → int
Decimal places used for every price shown.
final
flingCurve → Curve
Easing applied to the fling animation.
final
flingRatio → double
Multiplier applied to fling velocity.
final
flingTime → int
Duration of the fling animation, in milliseconds.
final
hashCode → int
The hash code for this object.
no setterinherited
hideGrid → bool
Hides the background grid.
final
horizontalLines → List<HorizontalLine>
Horizontal lines to draw, typically restored from storage.
final
indicators → List<Indicator>
The indicators to draw, in the order they were added.
final
infoDialogBuilder → Widget? Function(BuildContext, KLineEntity?, KLineEntity?)?
Replaces the built-in long-press info dialog.
final
infoDialogMaxWidth → double
Widest the long-press info dialog may grow before its rows ellipsise.
final
infoDialogWidth → double
Narrowest the long-press info dialog may be.
final
isLine → bool
Draws a filled close-price line instead of candles.
final
isOnDrag → ValueChanged<bool>?
Reports whether the user is currently dragging the chart.
final
isTapShowInfoDialog → bool
Opens the info dialog on tap as well as on long press.
final
isTrendLine → bool
Enables the drawing tools and their edit panel.
final
key → Key?
Controls how one widget replaces another widget in the tree.
finalinherited
materialInfoDialog → bool
Uses the Material info dialog rather than the Cupertino-styled one.
final
mBaseHeight → double?
Height of the candle area, before the volume and indicator panes are added below it.
final
onAddHorizontalLine → ValueChanged<HorizontalLine>?
Called when the user places or edits a horizontal line.
final
onAddTrendLine → ValueChanged<TrendLine>?
Called when the user finishes drawing or edits a trend line.
final
onAddVerticalLine → ValueChanged<VerticalLine>?
Called when the user places or edits a vertical line.
final
onLoadMore → ValueChanged<bool>?
Fires when the user scrolls past an edge; the flag is true at the right.
final
onRemoveHorizontalLine → ValueChanged<HorizontalLine>?
Called when the user deletes a horizontal line.
final
onRemoveTrendLine → ValueChanged<TrendLine>?
Called when the user deletes a trend line.
final
onRemoveVerticalLine → ValueChanged<VerticalLine>?
Called when the user deletes a vertical line.
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
showInfoDialog → bool
Enables the long-press info dialog.
final
showNowPrice → bool
Draws the current price line and its countdown to the candle close.
final
signals → List<SignalEntity>
Price markers painted over the candles.
final
timeFormat → List<String>
Date pattern for axis labels; see TimeFormat.
final
timeFrame → Duration
Duration of one candle, used to place lines and count down the close.
final
trendLines → List<TrendLine>
Trend lines to draw, typically restored from storage.
final
verticalLines → List<VerticalLine>
Vertical lines to draw, typically restored from storage.
final
verticalTextAlignment → VerticalTextAlignment
Which side the price axis labels sit on.
final
volHidden → bool
Hides the volume pane.
final
watermarkAssetPath → String
Asset path of an SVG watermark; a missing asset is ignored.
final
xFrontPadding → double
Empty space kept to the right of the newest candle.
final

Methods

createElement() → StatefulElement
Creates a StatefulElement to manage this widget's location in the tree.
inherited
createState() → State<KChartWidget>
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, int wrapWidth = 65}) → 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