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Location Wikipedia

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Landmarks can include Wikipedia data such as title, image title, URL, description, page summary, and language. The ExternalInfo class handles Wikipedia data and is provided by the ExternalInfoService class.

Check Wikipedia Data Availability​

Use the hasWikiInfo method to check if a landmark has Wikipedia data:

final bool hasExternalInfo = ExternalInfoService.hasWikiInfo(landmark);
danger

Do not modify Wikipedia-related fields in the extraInfo property when changing landmark data.

Get Wikipedia Information​

Obtain an ExternalInfo object using the requestWikiInfo method:

final requestListener = ExternalInfoService.requestWikiInfo(
  landmark,
  onComplete: (GemError err, ExternalInfo? externalInfo) {
    if (err != GemError.success) {
      showSnackbar("Error getting wiki info: $err");
      return;
    }

    // Data about the page
    final String title = externalInfo!.wikiPageTitle;
    final String content = externalInfo.wikiPageDescription;
    final String language = externalInfo.wikiPageLanguage;
    final String pageUrl = externalInfo.wikiPageUrl;
  },
);

The requestWikiInfo returns a progress listener that can cancel the request using the cancelWikiInfo method.

info

Wikipedia data is provided in the language specified in SDKSettings. See Internationalization for details.

Results:

  • Success: Returns GemError.success and a non-null ExternalInfo object
  • Failure: Returns null ExternalInfo and one of these errors:
    • GemError.invalidInput - Landmark does not contain Wikipedia information
    • GemError.connection - No internet connection available
    • GemError.notFound - Wikipedia information could not be retrieved
    • GemError.general - Unspecified error occurred

Get Wikipedia Image Data​

Access image details from the ExternalInfo class:

final int imgCount = externalInfo.imagesCount;
final String imageUrl = externalInfo.getWikiImageUrl(0);
final String imageDescription = externalInfo.getWikiImageDescription(0);
final String imageTitle = externalInfo.getWikiImageTitle(0);

Retrieve detailed image information using the requestWikiImageInfo method:

final imageInfoListener = externalInfo.requestWikiImageInfo(
  imageIndex: 0,
  onComplete: (GemError error, String? imageInfo) {
    if (error != GemError.success) {
      showSnackbar("Error getting wiki image info: $error");
      return;
    }

    // Do something with image info...
  },
);

The requestWikiImageInfo method returns a progress listener that can cancel the request using the cancelWikiImageInfoRequest method.

For getting the image data itself, use the requestWikiImage method to obtain a Img instance. The ExternalImageQuality enum allows specifying the desired image quality.

final imageDataListener = externalInfo.requestWikiImage(
  imageIndex: 0,
  quality: ExternalImageQuality.highImageQuality,
  onComplete: (GemError error, Img? image) {
    if (error != GemError.success) {
      showSnackbar("Error getting wiki image: $error");
      return;
    }

    // Do something with image...
  },
);
tip

It is recommended to use the requestWikiImageInfo method instead of using the getWikiImageUrl image URL directly. The getWikiImageUrl method provides a URL to the original image, which may have a very large size.

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