TooltipTextFormatterCallback typedef Null safety

TooltipTextFormatterCallback = String Function(dynamic actualValue, String formattedText)

Signature for formatting or changing the whole tooltip label text.

Implementation

typedef TooltipTextFormatterCallback = String Function(

    /// actualValue will be either [DateTime] or [double]
    /// based on given [values].
    dynamic actualValue,

    /// If the actual value is [double], it is formatted by [numberFormat] and
    /// if the actual value is [DateTime], it is formatted by [dateFormat].
    String formattedText);