registerHitZones method
Implementation
@override
void registerHitZones(Rect area, HitZoneSink sink) {
sink.add(area, id);
var x = area.x;
for (var i = 0; i < tabs.length; i++) {
final w = tabs[i].length + 4;
sink.add(
Rect(x, area.y, w, area.height),
Key.composite([id, 'tab', i]),
);
x += w;
}
}