Java tutorial
/* * Geopaparazzi - Digital field mapping on Android based devices * Copyright (C) 2010 HydroloGIS (www.hydrologis.com) * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package eu.geopaparazzi.library.routing.osmbonuspack; import java.io.BufferedReader; import java.io.FilterInputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.net.URL; import java.util.HashMap; import java.util.List; import org.apache.http.NameValuePair; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.Build; /** Useful functions and common constants. * @author M.Kergall */ public class BonusPackHelper { /** Log tag. */ public static final String LOG_TAG = "BONUSPACK"; /** resource id value meaning "undefined resource id" */ public static final int UNDEFINED_RES_ID = 0; /** User agent sent to services by default */ public static final String DEFAULT_USER_AGENT = "OsmBonusPack/1"; /** @return true if the device is the emulator, false if actual device. */ public static boolean isEmulator() { //return Build.MANUFACTURER.equals("unknown"); return ("google_sdk".equals(Build.PRODUCT) || "sdk".equals(Build.PRODUCT)); } public static BoundingBoxE6 cloneBoundingBoxE6(BoundingBoxE6 bb) { return new BoundingBoxE6(bb.getLatNorthE6(), bb.getLonEastE6(), bb.getLatSouthE6(), bb.getLonWestE6()); } /** @return the BoundingBox enclosing bb1 and bb2 BoundingBoxes */ public static BoundingBoxE6 concatBoundingBoxE6(BoundingBoxE6 bb1, BoundingBoxE6 bb2) { return new BoundingBoxE6(Math.max(bb1.getLatNorthE6(), bb2.getLatNorthE6()), Math.max(bb1.getLonEastE6(), bb2.getLonEastE6()), Math.min(bb1.getLatSouthE6(), bb2.getLatSouthE6()), Math.min(bb1.getLonWestE6(), bb2.getLonWestE6())); } /** * @return the whole content of the http request, as a string */ private static String readStream(HttpConnection connection) { String result = connection.getContentAsString(); return result; } /** sends an http request, and returns the whole content result in a String. * @param url * @return the whole content, or null if any issue. */ public static String requestStringFromUrl(String url) { HttpConnection connection = new HttpConnection(); connection.doGet(url); String result = readStream(connection); connection.close(); return result; } /** requestStringFromPost: do a post request to a url with name-value pairs, * and returns the whole content result in a String. * @param url * @param nameValuePairs * @return the content, or null if any issue. */ public static String requestStringFromPost(String url, List<NameValuePair> nameValuePairs) { HttpConnection connection = new HttpConnection(); connection.doPost(url, nameValuePairs); String result = readStream(connection); connection.close(); return result; } public static String convertStreamToString(InputStream is) throws Exception { BufferedReader reader = new BufferedReader(new InputStreamReader(is)); StringBuilder sb = new StringBuilder(); String line = null; while ((line = reader.readLine()) != null) { sb.append(line).append("\n"); } reader.close(); return sb.toString(); } /** * Loads a bitmap from a url. * @param url * @return the bitmap, or null if any issue. */ public static Bitmap loadBitmap(String url) { Bitmap bitmap = null; try { InputStream is = (InputStream) new URL(url).getContent(); if (is == null) return null; bitmap = BitmapFactory.decodeStream(new FlushedInputStream(is)); //Alternative providing better handling on loading errors? /* Drawable d = Drawable.createFromStream(new FlushedInputStream(is), null); if (is != null) is.close(); if (d != null) bitmap = ((BitmapDrawable)d).getBitmap(); */ } catch (Exception e) { e.printStackTrace(); return null; } return bitmap; } /** * Workaround on Android issue on bitmap loading * @see <a href="http://stackoverflow.com/questions/4601352/createfromstream-in-android-returning-null-for-certain-url">Issue</a> */ static class FlushedInputStream extends FilterInputStream { public FlushedInputStream(InputStream inputStream) { super(inputStream); } @Override public long skip(long n) throws IOException { long totalBytesSkipped = 0L; while (totalBytesSkipped < n) { long bytesSkipped = in.skip(n - totalBytesSkipped); if (bytesSkipped == 0L) { int byteValue = read(); if (byteValue < 0) { break; // we reached EOF } else { bytesSkipped = 1; // we read one byte } } totalBytesSkipped += bytesSkipped; } return totalBytesSkipped; } } /** * Parse a string-array resource with items like this: <item>key|value</item> * @param ctx * @param stringArrayResourceId * @return the keys=>values as an HashMap */ public static HashMap<String, String> parseStringMapResource(Context ctx, int stringArrayResourceId) { String[] stringArray = ctx.getResources().getStringArray(stringArrayResourceId); HashMap<String, String> map = new HashMap<String, String>(stringArray.length); for (String entry : stringArray) { String[] splitResult = entry.split("\\|", 2); map.put(splitResult[0], splitResult[1]); } return map; } }