Java tutorial
/* * This file provided by Facebook is for non-commercial testing and evaluation * purposes only. Facebook reserves all rights not expressly granted. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ package com.choices.imagecompare.urlsfetcher; import android.os.AsyncTask; import com.facebook.common.internal.Preconditions; import com.facebook.common.logging.FLog; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.Reader; import java.io.StringWriter; import java.net.HttpURLConnection; import java.net.URL; import java.util.ArrayList; import java.util.List; import javax.annotation.Nullable; /** * Helper that asynchronously fetches the list of image URIs from Imgur. */ public class ImageUrlsFetcher { /** * Imgur license key for use by the Fresco project. * <p/> * The rest of this class may be used freely according to the licence file, with the sole * exception of this variable. Any fork of this code or use in any other application, * whether open- or closed-source, must use a different client ID obtained from Imgur. * See the <a href="https://api.imgur.com/#register">Imgur API documentation</a>. */ private static final String IMGUR_CLIENT_ID = "Client-ID ccc6ca6a65ecdd8"; private static final String TAG = "FrescoSample"; public static final int SC_OK = 200; public static void getImageUrls(final ImageUrlsRequest request, final Callback callback) { new AsyncTask<Void, Void, List<String>>() { @Override protected List<String> doInBackground(Void... params) { return getImageUrls(request); } @Override protected void onPostExecute(List<String> result) { callback.onFinish(result); } }.execute(); } private static List<String> getImageUrls(ImageUrlsRequest request) { List<String> urls = new ArrayList<String>(); urls.add("http://pooyak.com/p/progjpeg/jpegload.cgi?o=3"); try { String rawJson = downloadContentAsString(request.getEndpointUrl()); if (rawJson == null) { return urls; } JSONObject json = new JSONObject(rawJson); JSONArray data = json.getJSONArray("data"); for (int i = 0; i < data.length(); i++) { JSONObject item = data.getJSONObject(i); if (!item.has("type")) { continue; } ImageFormat imageFormat = ImageFormat.getImageFormatForMime(item.getString("type")); ImageSize imageSize = request.getImageSize(imageFormat); if (imageSize != null) { urls.add(getThumbnailLink(item, imageSize)); } } } catch (Exception e) { FLog.e(TAG, "Exception fetching album", e); } return urls; } @Nullable private static String downloadContentAsString(String urlString) throws IOException { InputStream is = null; try { URL url = new URL(urlString); HttpURLConnection conn = (HttpURLConnection) url.openConnection(); conn.setRequestProperty("Authorization", IMGUR_CLIENT_ID); conn.setReadTimeout(10000 /* milliseconds */); conn.setConnectTimeout(15000 /* milliseconds */); conn.setRequestMethod("GET"); conn.setDoInput(true); // Starts the query conn.connect(); int response = conn.getResponseCode(); if (response != SC_OK) { FLog.e(TAG, "Album request returned %s", response); return null; } is = conn.getInputStream(); return readAsString(is); } finally { if (is != null) { is.close(); } } } /** * Reads an InputStream and converts it to a String. */ private static String readAsString(InputStream stream) throws IOException { StringWriter writer = new StringWriter(); Reader reader = new BufferedReader(new InputStreamReader(stream, "UTF-8")); while (true) { int c = reader.read(); if (c < 0) { break; } writer.write(c); } return writer.toString(); } private static String getThumbnailLink(final JSONObject json, final ImageSize imageSize) throws JSONException { Preconditions.checkNotNull(imageSize); final String originalUrl = json.getString("link"); if (imageSize == ImageSize.ORIGINAL_IMAGE) { return originalUrl; } final int dotPos = originalUrl.lastIndexOf('.'); final StringBuilder linkBuilder = new StringBuilder(originalUrl.length() + 1); return linkBuilder.append(originalUrl).insert(dotPos, imageSize.suffix).toString(); } public interface Callback { public void onFinish(List<String> results); } }