update series_legend.dart--- add onlyKeepSerie

[zheyxu]

click the legend and only keep the clicked legend. Greys others out

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[zheyxu]

charts_common/lib/src/chart/common/behavior/legend/series_legend.dart
/// Only keep data for a series on the chart by [seriesId].
///
/// The other entries in the legend for this series will be grayed out to indicate
/// that they are hidden.
@Protected
void onlyKeepSeries(String seriesId) {
if (!isSeriesAlwaysVisible(seriesId)) {
_allSeries?.forEach((element) => _hiddenSeriesList.add(element));
_hiddenSeriesList.remove(seriesId);
}
}

It can be used for the long press. When user long press the legend, only the clicked ones are kept. And other legends are greyed out.

[gjwgit]

Useful additional functionality that can then match longpress and double tap behaviour within the legend to common expectations as in plotly - i.e. toggle the display to show only the tapped series or all series.

Tested in simple flutter app - works as advertised.

[stuartmorgan]

This project is no longer maintained, and cannot accept any PRs. Community members interested in collaborating on a community-maintained fork can coordinate in this issue.