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Hints

  • 5 min to read

A hint is a small pop-up rectangle that shows information about a tapped series or point. A chart can display its hints as tooltips for all charts and as a Crosshair Cursor for a Cartesian Chart. A tooltip can display a beak which indicates its data point:

Tooltip example

In this guide, the tooltip is used to show common hint features.

How to: Allow end users to show hints

End-users can show or hide a tooltip by tapping a series or series point.

Displaying tooltips

The following code demonstrates how to enable hints:

Hint hint = new Hint();
hint.setEnabled(true);
chart.setHint(hint);

The table below contains symbols that configure the end-user capability to show tooltips:

Symbol Description
Hint The Chart hint-related settings' storage.
PieHint A pie hint.
HintBase.setEnabled(boolean) Specifies the value that indicates whether hints are enabled.
Chart.setHint(Hint) Specifies the chart hint settings.
PieChart.setHint(PieHint) Specifies a PieHint object that stores a Pie chart's hint-related settings.

How to: Configure a series representation in a hint

You can disable an individual series' hints, specify a text pattern to format values, and arrange these values within tooltips.

Tooltip text format

The code below shows how to specify a tooltip text's pattern.

PieSeriesHintOptions hintOptions = new PieSeriesHintOptions();
hintOptions.setPointTextPattern("{L}: {V} km²");
pieSeries.setHintOptions(hintOptions);

The following symbols configure series and hint interaction:

Symbol Description
PieSeries.setHintOptions(PieSeriesHintOptions) Specifies the PieSeriesHintOptions object that stores hint settings.
PieSeriesHintOptions The Pie series hint options storage.
Series.setHintOptions(SeriesHintOptions) Specifies the SeriesHintOptions object that specifies a series's hint text parameters.
SeriesHintOptions The series's hint options storage.
SeriesCrosshairOptions The series' Crosshair settings storage.
Note

You should use the SeriesHintOptions class for a Pie series and a Cartesian series within a Cartesian Chart that uses tooltips; in other cases you should use SeriesCrosshairOptions.

In the code above, the series placeholders (L and V) specify which series point values a tooltip should display in its text. The following label placeholders are available:

Placeholder Description
{S} Displays a series name.
{A} Displays a series point argument.
{L} Displays a pie series point label.
{V} Displays a series point value.
{VP} Displays a series point value as percentages.
{W} Displays a Bubble series point weight.
{O} Displays a financial series point open value.
{H} Displays a financial series point high value.
{L} Displays a financial series point low value.
{C} Displays a financial series point close value.
Note

These values can be formatted using default format strings after the $ sign. For example, in the {VP$#.##} string, VP is a placeholder, $ is a format string separator, and #.## is a format string.

How to: Show or hide tooltip programmatically

The chart can show or hide hints programmatically. The chart listener can also perform certain actions when a chart shows or hides a hint. For example, the following code demonstrates how to show the hint in the connected second chart when the first chart shows its hint using the chart delegate:

chart1.setHintListener(new ChartHintListener(chart2));
chart2.setHintListener(new ChartHintListener(chart1));

// The ChartHintListener implementation.
static class ChartHintListener implements HintListener{
    Chart mConnectedChart;
    public ChartHintListener(Chart connectedChart){
        mConnectedChart = connectedChart;
    }
    @Override
    public void onShow(HintInfo hintInfo) {
         mConnectedChart.showHint(hintInfo.getScreenPoint());
    }
    @Override
    public void onHide() {
         mConnectedChart.hideHint();
    }
}

The table below contains members that are the chart tooltip API.

Symbol Description
HintListener Listener for receiving events when a hint is shown or hidden.
ChartBase.showHint(int, int) Shows a hint for the specified data point.
ChartBase.showHint(Point) Shows a hint for the specified point.
ChartBase.hideHint() Listener for receiving events when a hint is shown or hidden.

How to: Customize a tooltip's appearance

You can customize a chart's tooltip appearance using the following highlighted parameters:

Tooltip appearance

The following code demonstrates how to configure the tooltip's appearance:

Hint hint = new Hint();
hint.setEnabled(true);
chart.setHint(hint);
HintStyle hintStyle = new HintStyle();
hintStyle.setMarkerSize(40);
hintStyle.setBackgroundColor(Color.DKGRAY);
hintStyle.setTextIndent(20);
hintStyle.setPadding(20,20,20,20);
hint.setStyle(hintStyle);
TextStyle textStyle = new TextStyle();
textStyle.setSize(30f);
textStyle.setColor(Color.WHITE);
textStyle.setPaintFlags(Paint.ANTI_ALIAS_FLAG);
textStyle.setLocale(Locale.US);
textStyle.setTypeface(Typeface.defaultFromStyle(Typeface.BOLD_ITALIC));
hintStyle.setTextStyle(textStyle);

The symbols below specify the tooltip's appearance.

Symbol Description
HintStyle Hint's appearance settings storage.com.devexpress.dxcharts.HintStyle)]
Hint.getStyle() Returns the HintStyle object that specifies a hint's appearance settings.
Hint.setStyle(HintStyle) Specifies the HintStyle object that defines a hint's appearance settings.
PieHintStyle The pie hint's appearance settings.
PieHint.getStyle() Returns a PieHintStyle object that specifies a hint's style.
PieHint.setStyle(PieHintStyle) Specifies a PieHintStyle object that specifies a hint's style.