问题描述
我收到 Pageviewbuilder
提供的数据的以下空检查错误;
The following _CastError was thrown building:
Null check operator used on a null value
When the exception was thrown,this was the stack:
#0 _StageBuilderState.createViewItem (package:speakoholic/screens/mainStage.dart:488:161)
#1 _StageBuilderState.build.<anonymous closure> (package:speakoholic/screens/mainStage.dart:138:18)
调用这个函数时第488行是speakcraft.tagname!
;
child: editIcon(
context: context,userid:speakcraft.userid!,audioid:speakcraft.audioid!,title: speakcraft.title!,tagname:speakcraft.tagname!),
第 138 行是 createViewItem
PageView.builder(
itemCount: widget.speakcrafts.length,itemBuilder: (context,int currentIndex) {
return createViewItem(widget.speakcrafts[currentIndex],context,currentIndex,widget.speakcrafts.length );
},);
这是函数;
Widget editIcon({
required BuildContext? context,required int? userid,required int? audioid,required String? title,required String? tagname}) {
return
FutureBuilder<int?>(
///some stuff
);
}
解决方法
问题是您正试图通过使用 Bang !
运算符(也称为空断言运算符)来使用不可为空的值来抛弃可空性:tagname:speakcraft.tagname!
。
另一方面,您的属性可以为空,因为 String? tagname
意味着 tagname
可以是 null
。
因此,为了避免这种情况,您可以更改您的 editIcon
方法:
editIcon(
...
tagname:speakcraft?.tagname ?? 'some default value'),