secondStringAtIndex method Null safety

  1. @override
String? secondStringAtIndex(
  1. int index
)
override

第二列选中字符串

Implementation

@override
String? secondStringAtIndex(int index) {
  if (index >= 0 && index < secondList.length) {
    return secondList[index];
  } else {
    return null;
  }
}