SciChart Accessibility Integration Guide

This guide helps you add accessibility support to SciChart. By following these steps, you will ensure that screen readers like TalkBack can interpret and vocalize chart interactions for visually impaired users.

Step 1: Extend SciChartSurface for Accessibility

Create a custom surface that enables navigation and interaction through accessibility tools.

Code Example

public class AccessibilityCustomSurface extends SciChartSurface {

    public AccessibilityCustomSurface(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) {
        // If the AccessibilityEvent isn't null, then add text to be announced when the SciChartSurface
        // is in focus in accessibility mode.
        if (event != null) {
            // This text will be announced when the SciChartSurface is in focus in accessibility mode
            event.getText().add("sci chart event");
        }
        return true;
    }

    @Override
    public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
        super.onInitializeAccessibilityNodeInfo(info);
        if (info != null) {
            // Set the SciChartSurface to be Clickable, Focusable and Scrollable
            info.setClickable(true);
            info.setFocusable(true);
            info.setScrollable(true);

            // Add an action, so that it is possible to click on SciChartSurface
            info.addAction(new AccessibilityNodeInfo.AccessibilityAction(
                    AccessibilityNodeInfo.ACTION_CLICK, "Action click"
            ));
        }
    }

    @Override
    public boolean performAccessibilityAction(int action, Bundle arguments) {
        // If the action is a click event, then return true to handle the event.
        if (action == AccessibilityNodeInfo.ACTION_CLICK) {
            // Any custom code that you need will go here
            return true;
        } else {
            return super.performAccessibilityAction(action, arguments);
        }
    }
}

What This Does

  • Makes the chart surface visible and interactive for screen readers.
  • Adds a verbal description: "sci chart event".
  • Supports accessible click actions.

Step 2: Announce Zoom or Pan (Visible Range Change)

When the chart’s visible range changes due to scroll or zoom, notify the screen reader so users stay informed.

Code Example

binding.surface.setImportantForAccessibility(View.IMPORTANT_FOR_ACCESSIBILITY_YES);

xAxis.setVisibleRangeChangeListener((axis, oldRange, newRange, isAnimating) -> {
    binding.surface.announceForAccessibility("visible range changed");
    binding.surface.sendAccessibilityEvent(AccessibilityEvent.TYPE_WINDOW_CONTENT_CHANGED);
});

What This Does

  • Announces "visible range changed" when user interacts with the chart.
  • Emits a window content change event for accessibility services.

Step 3: Provide Accessible Custom Tooltips

Customize tooltips to announce the current data point (X, Y, and series name) using announceForAccessibility().

Code Example

private static class FirstCustomSeriesInfoProvider extends DefaultXySeriesInfoProvider {
    @Override
    public ISeriesTooltip getSeriesTooltipInternal(Context context, XySeriesInfo<?> seriesInfo, Class<?> modifierType) {
        if (modifierType == RolloverModifier.class) {
            return new FirstCustomXySeriesTooltip(context, seriesInfo);
        } else {
            return super.getSeriesTooltipInternal(context, seriesInfo, modifierType);
        }
    }

    private static class FirstCustomXySeriesTooltip extends XySeriesTooltip {

        public FirstCustomXySeriesTooltip(Context context, XySeriesInfo<?> seriesInfo) {
            super(context, seriesInfo);
        }

        @Override
        protected void internalUpdate(XySeriesInfo seriesInfo) {
            super.internalUpdate(seriesInfo);
            SpannableStringBuilder sb = new SpannableStringBuilder();
            sb.append("X is ").append(seriesInfo.getFormattedXValue()).append(StringUtil.NEW_LINE);
            sb.append("Y is ").append(seriesInfo.getFormattedYValue()).append(StringUtil.NEW_LINE);

            if (seriesInfo.seriesName != null) {
                sb.append(seriesInfo.seriesName).append(StringUtil.NEW_LINE);
            }

            setText(sb);
            announceForAccessibility(sb.toString());

            setTooltipBackgroundColor(0xffe97064);
            setTooltipStroke(0xfff4840b);
            setTooltipTextColor(ColorUtil.White);
        }
    }
}

What This Does

  • Announces chart data values (X, Y, series name) when the tooltip appears.
  • Works with rollover modifiers and other dynamic interactions.
  • Enhances accessibility for real-time data updates.

Final Checklist

Feature Purpose Implemented In
Surface is accessible Lets users navigate chart surface Step 1
Zoom/pan announcement Alerts user to visible range changes Step 2
Tooltip speaks values Reads out data point details aloud Step 3
  • TalkBack (Android)
  • Accessibility Scanner (Google)
  • Manual screen reader interaction testing