decodeImageProvider static method

ImageProvider<Object>? decodeImageProvider(dynamic value, { bool validate = true, })

Decodes the given value to an ImageProvider. This expects a specific "type" attribute to be one of:

• asset
• memory
• network

The expected structure depends on the exact "type" value passed in.

Type: asset

{
  "assetName": <String>,
  "package": <String>,
  "type": "asset"
}

Type: memory

{
  "bytes": <String>,
  "scale": <double>,
  "type": "memory"
}

Type: network

{
  "headers": <Map<String, String>>,
  "type": "network",
  "scale": <double>,
  "url": <String>
}

Implementation

static ImageProvider? decodeImageProvider(
  dynamic value, {
  bool validate = true,
}) {
  ImageProvider? result;
  if (value is ImageProvider) {
    result = value;
  } else {
    assert(value == null || value['type'] is String);
    _checkSupported(
      'ImageProvider.type',
      [
        'asset',
        'network',
        'memory',
      ],
      value == null ? null : value['type'],
    );

    if (value != null) {
      assert(SchemaValidator.validate(
        schemaId: '$_baseSchemaUrl/image_provider',
        value: value,
        validate: validate,
      ));
      switch (value['type']) {
        case 'asset':
          result = AssetImage(
            value['assetName'],
            package: value['package'],
          );
          break;
        case 'memory':
          result = MemoryImage(
            base64Decode(value['bytes']),
            scale: JsonClass.parseDouble(value['scale'], 1.0)!,
          );
          break;
        case 'network':
          result = NetworkImage(
            value['url'],
            headers: value['headers'],
            scale: JsonClass.parseDouble(value['scale'], 1.0)!,
          );
          break;
      }
    }
  }

  return result;
}