The element type 'Set<Widget?>' can't be assigned to the list type 'Widget-CodePudding

I am using Flutter, and trying to show Image asset (question.answerImage) if it is not null. I wrote a code as follows, but it returns an error.

...
content: Column(children: [
             if (question.answerImage!=null){question.answerImage},
             ...

Error is written as follows:

The element type 'Set<Widget?>' can't be assigned to the list type 'Widget'.

How can I change the type Set<Widget?> to type Widget?

Best Regards,

CodePudding user response：

You are using if/else statements in Collection literals.

Remove the curly braces.

...
content: Column(children: [
         if (question.answerImage!=null)question.answerImage,
         ...

CodePudding user response：

If there is some widget other than 'question.answerImage',
you need to use 'spread operator' to seperate List to each Widget.
https://www.woolha.com/tutorials/dart-using-triple-dot-spread-operator-examples

[Example]

Column(children: [
    ...question.answerIamge,
    Container(...),
    Row(...),
  ]
)

...
content: Column(children: [
             if (question.answerImage!=null)...question.answerImage,
             ...