Location Wikipedia

Landmarks can include Wikipedia data such as title, image title, URL, description, page summary, language, and more. To demonstrate how to retrieve Wikipedia information, we introduce the ExternalInfo class, which handles Wikipedia data.

The ExternalInfo class is part of the core SDK and can be instantiated directly to access external information services.

Check if Wikipedia data is available​

Use the hasWikiInfo method of the ExternalInfo class to check if a landmark has Wikipedia data available:

• Kotlin
• Java

// Kotlin
val externalInfoService = ExternalInfo()
val hasExternalInfo = externalInfoService.hasWikiInfo(landmark)

//Java
ExternalInfo externalInfoService = new ExternalInfo();
boolean hasExternalInfo = externalInfoService.hasWikiInfo(landmark);

🚨 DANGER

Make sure the Wikipedia related fields from the extraInfo property of the UnlLandmark object are not tampered with if changes are made to the landmark data.

ExternalInfo class​

This class provides Wikipedia information for a landmark. Create an instance of ExternalInfo and use the requestWikiInfo method to retrieve Wikipedia data.

• Kotlin
• Java

// Kotlin
val externalInfoService = ExternalInfo()

val wikipediaProgressListener = UnlProgressListener.create(
    onStarted = {
        // Show loading indicator
        progressBar.visibility = View.VISIBLE
    },

    onCompleted = { errorCode, _ ->
        progressBar.visibility = View.GONE

        if (errorCode == UnlError.NoError) {
            // Success - access Wikipedia data
            SdkCall.execute {
                val title = externalInfoService.wikiPageTitle
                val content = externalInfoService.wikiPageDescription
                val language = externalInfoService.wikiPageLanguage
                val pageUrl = externalInfoService.wikiPageURL

                // Use the retrieved data
                displayWikipediaInfo(title, content, language, pageUrl)
            }
        } else {
            // Handle error
            showDialog("Error getting wiki info: ${UnlError.getMessage(errorCode)}")
        }
    },

    postOnMain = true
)

SdkCall.execute {
    externalInfoService.requestWikiInfo(landmark, wikipediaProgressListener)
}

// Java
ExternalInfo externalInfoService = new ExternalInfo();

UnlProgressListener wikipediaProgressListener = UnlProgressListener.create(
    () -> {
        // Show loading indicator
        progressBar.setVisibility(View.VISIBLE);
    },
    (errorCode, hint) -> {
        progressBar.setVisibility(View.GONE);

        if (errorCode == UnlError.NoError) {
            // Success - access Wikipedia data
            SdkCall.execute(() -> {
                String title = externalInfoService.getWikiPageTitle();
                String content = externalInfoService.getWikiPageDescription();
                String language = externalInfoService.getWikiPageLanguage();
                String pageUrl = externalInfoService.getWikiPageURL();

                // Use the retrieved data
                displayWikipediaInfo(title, content, language, pageUrl);
            });
        } else {
            // Handle error
            showDialog("Error getting wiki info: " + UnlError.getMessage(errorCode));
        }
    },
    true
);

SdkCall.execute(() -> {
    externalInfoService.requestWikiInfo(landmark, wikipediaProgressListener);
});

The requestWikiInfo method triggers a progress listener that will be notified when the operation completes. You can cancel the request using the cancelWikiInfo method.

📝 INFO

Wikipedia data is provided in the language specified in UnlSdkSettings.

The method provides a result based on the outcome of the operation:

• On success returns UnlError.NoError and the Wikipedia data is available through the ExternalInfo properties.

• On failure returns one of the following UnlError values:

• UnlError.InvalidInput : The specified landmark does not contain Wikipedia-related information.
• UnlError.Connection : No internet connection is available.
• UnlError.NotFound : Wikipedia information could not be retrieved for the given landmark.
• UnlError.General : An unspecified error occurred.

Wikipedia image data​

The ExternalInfo class provides the following details regarding images:

• Kotlin
• Java

// Kotlin
SdkCall.execute {
    val imgCount = externalInfoService.wikiImagesCount
    val imageUrl = externalInfoService.getWikiImageURL(0)
    val imageDescription = externalInfoService.getWikiImageDescription(0)
    val imageTitle = externalInfoService.getWikiImageTitle(0)
}

// Java
SdkCall.execute(() -> {
    int imgCount = externalInfoService.getWikiImagesCount();
    String imageUrl = externalInfoService.getWikiImageURL(0);
    String imageDescription = externalInfoService.getWikiImageDescription(0);
    String imageTitle = externalInfoService.getWikiImageTitle(0);
});

Requesting Wikipedia image content​

You can request the actual image content using the requestWikiImage method:

• Kotlin
• Java

// Kotlin
val image = UnlImage()
val externalInfoService = ExternalInfo()
val imageProgressListener = UnlProgressListener.create(
    onCompleted = { errorCode, _ ->
        if (errorCode == UnlError.NoError) {
            // UnlImage loaded successfully
            SdkCall.execute {
                //val bitmap = image.asBitmap(width, height)
                // Display the image
                //imageView.setImageBitmap(bitmap)
            }
        }
    },
    postOnMain = true
)
externalInfoService.requestWikiImage(
    imageProgressListener,
    image,
    nImageIdx = 0,
    EExternalImageQuality.Medium
)

// Java
UnlImage image = new UnlImage();
ExternalInfo externalInfoService = new ExternalInfo();
UnlProgressListener imageProgressListener = UnlProgressListener.create(
    (errorCode, hint) -> {
        if (errorCode == UnlError.NoError) {
            // UnlImage loaded successfully
            SdkCall.execute(() -> {
                //Bitmap bitmap = image.asBitmap(width, height);
                // Display the image
                //imageView.setImageBitmap(bitmap);
            });
        }
    },
    true
);
externalInfoService.requestWikiImage(
    imageProgressListener,
    image,
    0,
    EExternalImageQuality.Medium
);

Wikipedia image information​

Detailed information about an image can be retrieved using the requestWikiImageInfo method:

• Kotlin
• Java

// Kotlin
val externalInfoService = ExternalInfo()
val result = GemString()
val imageInfoListener = UnlProgressListener.create(
    onCompleted = { errorCode, _ ->
        if (errorCode == UnlError.NoError) {
            // UnlImage info retrieved successfully
            val imageInfo = result.value// GemString result
            // Process the image information
        } else {
            showDialog("Error getting wiki image info: ${UnlError.getMessage(errorCode)}")
        }
    },
    postOnMain = true
)
externalInfoService.requestWikiImageInfo(imageInfoListener, nImageIdx = 0, result)

// Java
ExternalInfo externalInfoService = new ExternalInfo();
GemString result = new GemString();
UnlProgressListener imageInfoListener = UnlProgressListener.create(
    (errorCode, hint) -> {
        if (errorCode == UnlError.NoError) {
            // UnlImage info retrieved successfully
            String imageInfo = result.getValue(); // GemString result
            // Process the image information
        } else {
            showDialog("Error getting wiki image info: " + UnlError.getMessage(errorCode));
        }
    },
    true
);
externalInfoService.requestWikiImageInfo(imageInfoListener, 0, result);

Canceling requests​

You can cancel various requests using the available cancel methods:

• Kotlin
• Java

// Kotlin
// Cancel main Wikipedia info request
externalInfoService.cancelWikiInfo()

// Cancel specific image content request
externalInfoService.cancelWikiImageContentRequest(imageProgressListener)

// Cancel specific image info request
externalInfoService.cancelWikiImageInfoRequest(imageInfoListener)

//Java
// Cancel main Wikipedia info request
externalInfoService.cancelWikiInfo();

// Cancel specific image content request
externalInfoService.cancelWikiImageContentRequest(imageProgressListener);

// Cancel specific image info request
externalInfoService.cancelWikiImageInfoRequest(imageInfoListener);