Integrate API for displaying featured images

app/build.gradle

@@ -49,6 +49,8 @@ dependencies {
     implementation 'com.jakewharton.rxbinding2:rxbinding-appcompat-v7:2.0.0'
     implementation 'com.jakewharton.rxbinding2:rxbinding-design:2.0.0'
 
+    implementation 'org.jsoup:jsoup:1.11.3'
+
     implementation 'com.facebook.fresco:fresco:1.5.0'
     implementation 'com.facebook.stetho:stetho:1.5.0'
 

app/src/main/AndroidManifest.xml

@@ -92,8 +92,9 @@
             android:label="@string/navigation_item_notification" />
 
         <activity
-            android:name=".featured.FeaturedImagesActivity"
-            android:label="@string/title_activity_featured_images" />
+            android:name=".category.CategoryImagesActivity"
+            android:label="@string/title_activity_featured_images"
+            android:parentActivityName=".contributions.ContributionsActivity" />
 
         <service android:name=".upload.UploadService" />
 

app/src/main/java/fr/free/nrw/commons/category/CategoryImageController.java

@@ -0,0 +1,29 @@
+package fr.free.nrw.commons.category;
+
+import java.util.List;
+
+import javax.inject.Inject;
+import javax.inject.Singleton;
+
+import fr.free.nrw.commons.Media;
+import fr.free.nrw.commons.mwapi.MediaWikiApi;
+
+@Singleton
+public class CategoryImageController {
+
+    private MediaWikiApi mediaWikiApi;
+
+    @Inject
+    public CategoryImageController(MediaWikiApi mediaWikiApi) {
+        this.mediaWikiApi = mediaWikiApi;
+    }
+
+    /**
+     * Takes a category name as input and calls the API to get a list of images for that category
+     * @param categoryName
+     * @return
+     */
+    public List<Media> getCategoryImages(String categoryName) {
+        return mediaWikiApi.getCategoryImages(categoryName);
+    }
+}

app/src/main/java/fr/free/nrw/commons/category/CategoryImageUtils.java

@@ -0,0 +1,225 @@
+package fr.free.nrw.commons.category;
+
+import org.jsoup.Jsoup;
+import org.w3c.dom.Element;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
+
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.List;
+
+import javax.annotation.Nullable;
+
+import fr.free.nrw.commons.Media;
+import timber.log.Timber;
+
+public class CategoryImageUtils {
+
+    /**
+     * The method iterates over the child nodes to return a list of Media objects
+     * @param childNodes
+     * @return
+     */
+    public static List<Media> getMediaList(NodeList childNodes) {
+        List<Media> categoryImages = new ArrayList<>();
+        for (int i = 0; i < childNodes.getLength(); i++) {
+            Node node = childNodes.item(i);
+            categoryImages.add(getMediaFromPage(node));
+        }
+
+        return categoryImages;
+    }
+
+    /**
+     * Creates a new Media object from the XML response as received by the API
+     * @param node
+     * @return
+     */
+    private static Media getMediaFromPage(Node node) {
+        Media media = new Media(null,
+                getImageUrl(node),
+                getFileName(node),
+                getDescription(node),
+                getDataLength(node),
+                getDateCreated(node),
+                getDateCreated(node),
+                getCreator(node)
+        );
+
+        media.setLicense(getLicense(node));
+
+        return media;
+    }
+
+    /**
+     * Extracts the filename of the uploaded image
+     * @param document
+     * @return
+     */
+    private static String getFileName(Node document) {
+        Element element = (Element) document;
+        return element.getAttribute("title");
+    }
+
+    /**
+     * Extracts the image description for that particular upload
+     * @param document
+     * @return
+     */
+    private static String getDescription(Node document) {
+        return getMetaDataValue(document, "ImageDescription");
+    }
+
+    /**
+     * Extracts license information from the image meta data
+     * @param document
+     * @return
+     */
+    private static String getLicense(Node document) {
+        return getMetaDataValue(document, "License");
+    }
+
+    /**
+     * Returns the parsed value of artist from the response
+     * The artist information is returned as a HTML string from the API. Jsoup library parses the HTML string
+     * to extract just the text value
+     * @param document
+     * @return
+     */
+    private static String getCreator(Node document) {
+        String artist = getMetaDataValue(document, "Artist");
+        if (artist != null) {
+            return Jsoup.parse(artist).text();
+        }
+        return null;
+    }
+
+    /**
+     * Returns the parsed date of creation of the image
+     * @param document
+     * @return
+     */
+    private static Date getDateCreated(Node document) {
+        String dateTime = getMetaDataValue(document, "DateTime");
+        if (dateTime != null && !dateTime.equals("")) {
+            SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
+            try {
+                return format.parse(dateTime);
+            } catch (ParseException e) {
+                Timber.d("Error occurred while parsing date %s", dateTime);
+                return new Date();
+            }
+        }
+        return new Date();
+    }
+
+    /**
+     * @param document
+     * @return Returns the url attribute from the imageInfo node
+     */
+    private static String getImageUrl(Node document) {
+        Element element = (Element) getImageInfo(document);
+        if (element != null) {
+            return element.getAttribute("url");
+        }
+        return null;
+    }
+
+    /**
+     * Takes the node document and gives out the attribute length from the node document
+     * @param document
+     * @return
+     */
+    private static long getDataLength(Node document) {
+        Element element = (Element) document;
+        if (element != null) {
+            String length = element.getAttribute("length");
+            if (length != null && !length.equals("")) {
+                return Long.parseLong(length);
+            }
+        }
+        return 0L;
+    }
+
+    /**
+     * Generic method to get the value of any meta as returned by the getMetaData function
+     * @param document node document as returned by API
+     * @param metaName the name of meta node to be returned
+     * @return
+     */
+    private static String getMetaDataValue(Node document, String metaName) {
+        Element metaData = getMetaData(document, metaName);
+        if (metaData != null) {
+            return metaData.getAttribute("value");
+        }
+        return null;
+    }
+
+    /**
+     * Generic method to return an element taking the node document and metaName as input
+     * @param document node document as returned by API
+     * @param metaName the name of meta node to be returned
+     * @return
+     */
+    @Nullable
+    private static Element getMetaData(Node document, String metaName) {
+        Node extraMetaData = getExtraMetaData(document);
+        if (extraMetaData != null) {
+            Node node = getNode(extraMetaData, metaName);
+            if (node != null) {
+                return (Element) node;
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Extracts extmetadata from the response XML
+     * @param document
+     * @return
+     */
+    @Nullable
+    private static Node getExtraMetaData(Node document) {
+        Node imageInfo = getImageInfo(document);
+        if (imageInfo != null) {
+            return getNode(imageInfo, "extmetadata");
+        }
+        return null;
+    }
+
+    /**
+     * Extracts the ii node from the imageinfo node
+     * @param document
+     * @return
+     */
+    @Nullable
+    private static Node getImageInfo(Node document) {
+        Node imageInfo = getNode(document, "imageinfo");
+        if (imageInfo != null) {
+            return getNode(imageInfo, "ii");
+        }
+        return null;
+    }
+
+    /**
+     * Takes a parent node as input and returns a child node if present
+     * @param node parent node
+     * @param nodeName child node name
+     * @return
+     */
+    @Nullable
+    public static Node getNode(Node node, String nodeName) {
+        NodeList childNodes = node.getChildNodes();
+        for (int i = 0; i < childNodes.getLength(); i++) {
+            Node nodeItem = childNodes.item(i);
+            Element item = (Element) nodeItem;
+            if (item.getTagName().equals(nodeName)) {
+                return nodeItem;
+            }
+        }
+        return null;
+    }
+}