Decoding base64 string to image in flutter (Invalid character exception)

Question

Basically I'm trying to convert a base64 jpeg image to normal image in flutter using

Image.memory(base64Decode(stringBase64))

the image initially used to be jp/2 format which isn't supported by flutter so i converted the jp/2 base64 string to bitmap in java and then to base64 string jpeg to be able to decode it in flutter using this code :

public static String encodeToBase64(Bitmap image)
{
    Bitmap immagex=image;
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    immagex.compress(Bitmap.CompressFormat.JPEG, 100, baos);
    byte[] b = baos.toByteArray();
    String imageEncoded = Base64.encodeToString(b, Base64.DEFAULT);

    return imageEncoded;
}

how ever when i try to decode this base64 string in flutter i'm getting this error

Invalid character (at character 77) /9j/4AAQSkZJRgABAQAAAQABAAD/4gIoSUNDX1BST0ZJTEUAAQEAAAIYAAAAAAIQAABtbnRyUkdC

which is pointing to the last C in the given line.

i don't seem understand where does the issue come from since i can convert my base64 string to image online but in flutter it throws that exception every time

Most likely your base64 string contains whitespace (such as being split across multiple lines). [Dart's base64 decoder does not accept whitespace](https://github.com/dart-lang/sdk/issues/29434), so you will need to remove it yourself first (e.g. `base64Decode(stringBase64.replaceAll(RegExp(r'\s'), ''))`). — jamesdlin, Jul 24 '22 at 07:56

score 0 · Accepted Answer · answered Jul 24 '22 at 18:41

0

thank you very much @Jamesdlin for the solution that was given in the comments

The issue was due to whitespace in the base64 string , solved by using

 base64.decode(photoBase64.replaceAll(RegExp(r'\s'), '')),

answered Jul 24 '22 at 18:41

Ateeg Razi

5
3

score 0 · Answer 2 · answered Dec 15 '22 at 16:37

If your URI contains data after the comma as it is defined by RFC-2397. Dart's Uri class is based on RFC-3986, so you can't use it.

Split the string by a comma and take the last part of it:

String uri = 'data:image/gif;base64,...';
Uint8List _bytes = base64.decode(uri.split(',').last);

REFERENCE: https://stackoverflow.com/a/59015116/12382178

Decoding base64 string to image in flutter (Invalid character exception)

2 Answers2