Handling Chart Events

From Documentation
Handling Chart Events

ZK Charts fire events when a user is interacting with the chart, we can, therefore, declare a method to listen to the event and handle the event data.


ChartsEvent represents an event triggered by user's interaction. Please check out event.zul in the example project to see events firing.

Shifting Points Example

If we want to shift the point's position when user clicks the bubble, we can listen the onPlotClick event and retrieve the point being clicked. Then update the point's position like below:


<charts id="chart" type="bubble" apply="org.zkoss.zkcharts.essentials.ShiftComposer"/>


 1 public class ShiftComposer extends SelectorComposer<Window> {
 2     @Wire
 3     Charts chart;
 5     public void doAfterCompose(Window comp) throws Exception {
 6         super.doAfterCompose(comp);
 7         // initial series data
 8         initPoints();
 9         // hide some unnecessary options
10         hideOptions();
11     }
13     @Listen("onPlotClick = #chart")
14     public void shiftPoint(ChartsEvent event) {
15         // retrieve the point object.
16         Point point = event.getPoint();
17         // shift the point by updating its x value.
18         point.setX(point.getX().intValue() + random() / 10);
19     }
21 ...
22 }

Congratulations! Now you can interact with the chart. Here is what it shows:


ClickEvent Usage

What if we want to select the bubble and move it to the location where the mouse was clicked? It can be done by modifying the previous sample code as below:

 1     ...
 3     public void doAfterCompose(Window comp) throws Exception {
 4         super.doAfterCompose(comp);
 6         // initial series data
 7         initPoints();
 8         // hide some unnecessary options
 9         hideOptions();
10         // allow point select
11         chart.getPlotOptions().getBubble().setAllowPointSelect(true);
12     }
14     @Listen("onClick = #chart")
15     public void movePoint(ChartsClickEvent event) {
16     	for (Point point: chart.getSelectedPoints()) {
17     		point.update(event.getXAxis(), event.getYAxis(), point.getHigh());
18     		point.setSelected(false);
19     	}
20     }
22     ...

Supported ChartsEvent

EventName Description
onPlotClick Fires when the series is clicked, and it will pass the nearest point as a parameter.
onPlotCheckboxClick Fires when the checkbox next to the series' name in the legend is clicked.
onPlotLegendItemClick Fires when the legend item belonging to the series is clicked.

(Not applicable to pies).

onPlotShow Fires when the series is shown after chart generation time, by clicking the legend item.

(Not applicable to pies).

onPlotHide Fires when the series is hidden after chart generation time, by clicking the legend item.

(Not applicable to pies).

onPlotMouseOver Fires when the mouse enters the graph.
onPlotMouseOut Fires when the mouse leaves the graph.
onPlotSelect Fires when selecting a point from a series.

The zkcharts doesn't send this event before you enable "point select" by Charts.getPlotOptions().getSeries().setAllowPointSelect(true); Reference: http://api.highcharts.com/highcharts#plotOptions.series.point.events

onPlotUnselect Fires when unselecting a point from a series.
onPlotDrillUp Fires when drilling up from a drilldown series.
onPlotDrillDown Fires when a drilldown point is clicked, before the new series is added.
onSelection When you allow zooming by Charts.setZoomType(), it's fired when you drag your pointer within the chart. ZK will pass a ChartsSelectionEvent into an event listener.
onClick Fires when you click within a chart, ZK will pass ChartsClickEvent.


  • see ChartsEvents for more details.
  • onPlotShow, onPlotHide, and onPlotLegendItemClick are not applicable on a pie chart because they are fired when a legend represents represents a series. But a legend in a pie chart represents a point, so ZKCharts doesn't fire those events for a pie chart.

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Last Update : 2023/02/07

Copyright © Potix Corporation. This article is licensed under GNU Free Documentation License.