Panoramio Android源码

/* * Copyright (C) 2008 Google Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.google.android.panoramio; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpGet; import org.apache.http.impl.client.DefaultHttpClient; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import android.content.Context; import android.database.DataSetObserver; import android.graphics.Bitmap; import android.os.Handler; import android.util.Log; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.lang.ref.WeakReference; import java.net.URI; import java.util.ArrayList; /** * This class is responsible for downloading and parsing the search results for * a particular area. All of the work is done on a separate thread, and progress * is reported back through the DataSetObserver set in * {@link #addObserver(DataSetObserver). State is held in memory by in memory * maintained by a single instance of the ImageManager class. */ public class ImageManager { private static final String TAG = "Panoramio"; /** * Base URL for Panoramio's web API */ private static final String THUMBNAIL_URL = "//www.panoramio.com/map/get_panoramas.php?order=popularity&set=public&from=0&to=20&miny=%f&minx=%f&maxy=%f&maxx=%f&size=thumbnail"; /** * Used to post results back to the UI thread */ private Handler mHandler = new Handler(); /** * Holds the single instance of a ImageManager that is shared by the process. */ private static ImageManager sInstance; /** * Holds the images and related data that have been downloaded */ private ArrayList<PanoramioItem> mImages = new ArrayList<PanoramioItem>(); /** * Observers interested in changes to the current search results */ private ArrayList<WeakReference<DataSetObserver>> mObservers = new ArrayList<WeakReference<DataSetObserver>>(); /** * True if we are in the process of loading */ private boolean mLoading; private Context mContext; /** * Key for an Intent extra. The value is the zoom level selected by the user. */ public static final String ZOOM_EXTRA = "zoom"; /** * Key for an Intent extra. The value is the latitude of the center of the search * area chosen by the user. */ public static final String LATITUDE_E6_EXTRA = "latitudeE6"; /** * Key for an Intent extra. The value is the latitude of the center of the search * area chosen by the user. */ public static final String LONGITUDE_E6_EXTRA = "longitudeE6"; /** * Key for an Intent extra. The value is an item to display */ public static final String PANORAMIO_ITEM_EXTRA = "item"; public static ImageManager getInstance(Context c) { if (sInstance == null) { sInstance = new ImageManager(c.getApplicationContext()); } return sInstance; } private ImageManager(Context c) { mContext = c; } /** * @return True if we are still loading content */ public boolean isLoading() { return mLoading; } /** * Clear all downloaded content */ public void clear() { mImages.clear(); notifyObservers(); } /** * Add an item to and notify observers of the change. * @param item The item to add */ private void add(PanoramioItem item) { mImages.add(item); notifyObservers(); } /** * @return The number of items displayed so far */ public int size() { return mImages.size(); } /** * Gets the item at the specified position */ public PanoramioItem get(int position) { return mImages.get(position); } /** * Adds an observer to be notified when the set of items held by this ImageManager changes. */ public void addObserver(DataSetObserver observer) { WeakReference<DataSetObserver> obs = new WeakReference<DataSetObserver>(observer); mObservers.add(obs); } /** * Load a new set of search results for the specified area. * * @param minLong The minimum longitude for the search area * @param maxLong The maximum longitude for the search area * @param minLat The minimum latitude for the search area * @param maxLat The minimum latitude for the search area */ public void load(float minLong, float maxLong, float minLat, float maxLat) { mLoading = true; new NetworkThread(minLong, maxLong, minLat, maxLat).start(); } /** * Called when something changes in our data set. Cleans up any weak references that * are no longer valid along the way. */ private void notifyObservers() { final ArrayList<WeakReference<DataSetObserver>> observers = mObservers; final int count = observers.size(); for (int i = count - 1; i >= 0; i--) { WeakReference<DataSetObserver> weak = observers.get(i); DataSetObserver obs = weak.get(); if (obs != null) { obs.onChanged(); } else { observers.remove(i); } } } /** * This thread does the actual work of downloading and parsing data. * */ private class NetworkThread extends Thread { private float mMinLong; private float mMaxLong; private float mMinLat; private float mMaxLat; public NetworkThread(float minLong, float maxLong, float minLat, float maxLat) { mMinLong = minLong; mMaxLong = maxLong; mMinLat = minLat; mMaxLat = maxLat; } @Override public void run() { String url = THUMBNAIL_URL; url = String.format(url, mMinLat, mMinLong, mMaxLat, mMaxLong); try { URI uri = new URI("http", url, null); HttpGet get = new HttpGet(uri); HttpClient client = new DefaultHttpClient(); HttpResponse response = client.execute(get); HttpEntity entity = response.getEntity(); String str = convertStreamToString(entity.getContent()); JSONObject json = new JSONObject(str); parse(json); } catch (Exception e) { Log.e(TAG, e.toString()); } } private void parse(JSONObject json) { try { JSONArray array = json.getJSONArray("photos"); int count = array.length(); for (int i = 0; i < count; i++) { JSONObject obj = array.getJSONObject(i); long id = obj.getLong("photo_id"); String title = obj.getString("photo_title"); String owner = obj.getString("owner_name"); String thumb = obj.getString("photo_file_url"); String ownerUrl = obj.getString("owner_url"); String photoUrl = obj.getString("photo_url"); double latitude = obj.getDouble("latitude");