To add a clickable button to a tooltip you should first make sure that correct options for the tooltip are used.
See the green highlight in the image attached.
- useHTML needs to be set to true to enable adding of HTML structures, like button
- pointerEvent in the tooltip's style needs to be set to "auto" to enable click events
Next, you could write the onclick functions for the button(s) as a string and use
For native Android callback to on click events for specific chart elements you could check the documentation section in the highcharts-android GitHub repository in here.