Error: Not a constant expression in Flutter

Question

I using the demo from this library and it works perfectly. But when I implement in my project, I get error on this line

Error: Not a constant expression. const AssetImage(snapshot.data[index]),

My Container is wrapping in InkWell.

  InkWell(
      child: Container(
                 padding:
                      EdgeInsets.zero,
                     height: 150,
                      width: 150,
                      decoration:
                            BoxDecoration(
                                      image: DecorationImage(
                                       image: AssetImage(snapshot.data[index]),
                                            fit: BoxFit .fill),
                                  ),
                           ),
      onTap: () {
               print('The value is ' + snapshot .data[index]);
                    Navigator.push(
                      context,
                      MaterialPageRoute(
                        builder:
                         (context) =>
                            const FullScreenWrapper(imageProvider:const AssetImage(snapshot.data[index]),  // here the error
                                    )));
               },
       ),

Here the printed value

The value is /storage/emulated/0/Android/data/xxx/files/Pictures/scaled_1572364487252xxx.jpg

If I remove the const, I get others error

Arguments of a constant creation must be constant expressions. Try making the argument a valid constant, or use 'new' to call the constructor.

I even tried using new but to no avail.

score 65 · Accepted Answer · answered Nov 13 '19 at 08:28

65

Here const AssetImage(snapshot.data[index]) you are using a const constructor. The compiler is expecting a compile time constant and is complaining because the arguments you are passing in are not constant but depend on the runtime value of snapshot.data.

If you simply remove the const keyword it should compile without errors.

answered Nov 13 '19 at 08:28

lyio

1,237
12
13

Unfortunately I gives me anaother error `Arguments of a constant creation must be constant expressions. Try making the argument a valid constant, or use 'new' to call the constructor.` – Tony Nov 13 '19 at 08:33
5

I guess you have to remove the `const` before the `FullScreenWrapper` as well. – lyio Nov 13 '19 at 08:34
2

I think I might have copied my code from somewhere and didn't realize it had a leading "const" keyword in front of one of my widgets. Removing it solved the problem. – Ulysses Alves Oct 01 '20 at 17:49
accurate... Thanks for this – Zionnite Apr 21 '22 at 07:37

score -4 · Answer 2 · answered Jul 03 '22 at 18:43

-4

Make sure it has an internet device or simulator

answered Jul 03 '22 at 18:43

ehsan mosavi

43
2

erm..this doesn't make sense at all – Tony Oct 09 '22 at 15:19

Error: Not a constant expression in Flutter

2 Answers2