BonusPackHelper.java

package org.osmdroid.utils;

import java.io.FileNotFoundException;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.List;

import org.apache.http.NameValuePair;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Build;
import android.util.Log;

/**
 * Useful functions and common constants.
 * @author M.Kergall
 */
public class BonusPackHelper {

	/** Log tag. */
	public static final String LOG_TAG = "BONUSPACK";

	/** 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));
	}

	/**
	 * @param connection
	 *            ...
	 * @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;
	}

	/**
	 * 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();
			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 (FileNotFoundException e) {
			Log.d(BonusPackHelper.LOG_TAG, "image not available: " + url);
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		}
		return bitmap;
	}

	/**
	 * Workaround on Android issue see
	 * http://stackoverflow.com/questions/4601352
	 * /createfromstream-in-android-returning-null-for-certain-url
	 */
	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

					bytesSkipped = 1; // we read one byte
				}
				totalBytesSkipped += bytesSkipped;
			}
			return totalBytesSkipped;
		}
	}
}