1、回调函数的时候，报错：
════════ Exception caught by gesture ═══════════════════════════════════════════════════════════════ The following NoSuchMethodError was thrown while handling a gesture: The method ‘call‘ was called on null. Receiver: null Tried calling: call() When the exception was thrown, this was the stack: #0 Object.noSuchMethod (dart:core-patch/object_patch.dart:53:5) #1 _BillAddPageState.build.<anonymous closure>.<anonymous closure> (package:flutter_bcd/pages/bill/bill_add_page.dart:139:19) #2 _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:706:14) #3 _InkResponseState.build.<anonymous closure> (package:flutter/src/material/ink_well.dart:789:36) #4 GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:182:24) ... Handler: "onTap"
return InkWell(
onTap: () {
setState(() {
_selectedIndex = index;
});
print(_scaffoldKey);
// 调用 回调函数必须加括号
_showBottomSheetCallback();
},
child: Container(
alignment: Alignment.center,
padding: EdgeInsets.only(bottom: 10),
color: flag ? Colors.amber : Colors.transparent,
child: Column(
children: <Widget>[
Expanded(child: categoryList[index].icon),
Text(
categoryList[index].title,
style: TextStyle(
fontSize: 14,
color: Color(0xFF333333),
),
),
],
),
));
空指针这种错误，一般是自己的程序逻辑问题：
解决方法就是判空：
// 调用 回调函数必须加括号
if (_showBottomSheetCallback != null) {
_showBottomSheetCallback();
}
原文：https://www.cnblogs.com/hoge66/p/13286929.html