Java tutorial
/* Copyright (C) 2012 Dave Berkeley android@rotwang.co.uk 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 2 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, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ package uk.co.rotwang.cosm; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.net.HttpURLConnection; import java.net.URL; import java.net.URLConnection; import java.net.URLEncoder; import java.util.Random; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import android.app.PendingIntent; import android.app.Service; import android.appwidget.AppWidgetManager; import android.appwidget.AppWidgetProvider; import android.content.Context; import android.content.Intent; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Color; import android.os.IBinder; import android.util.Log; import android.widget.RemoteViews; /** * Define a widget to display COSM graph and data. */ public class CosmWidget extends AppWidgetProvider { private static final String TAG = "CosmWidget"; @Override public void onUpdate(Context context, AppWidgetManager manager, int[] widgetIds) { // To prevent any ANR timeouts, we perform the update in a service for (int wid : widgetIds) { // Update each widget that requests it Intent intent = new Intent(context, UpdateService.class); Settings.setWidgetId(intent, wid); context.startService(intent); } } /* @Override public void onReceive(Context context, Intent intent) { super.onReceive(context, intent); Log.v(TAG, "onReceive " + intent.getAction()); // String action = intent.getAction(); // on each widget being deleted : ACTION_APPWIDGET_DELETED // on last widget being removed : ACTION_APPWIDGET_DISABLED // on first widget being added : ACTION_APPWIDGET_ENABLED // on widget being created + periodic : ACTION_APPWIDGET_UPDATE if (intent.getAction().equals(AppWidgetManager.ACTION_APPWIDGET_UPDATE)) { // updated (possibly with new parameters) // widget(s) in EXTRA_APPWIDGET_IDS Bundle extras = intent.getExtras(); if (extras != null) { int[] wids = extras.getIntArray(AppWidgetManager.EXTRA_APPWIDGET_IDS); for (int wid : wids) { long period = 10000; AlarmManager alarm = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE); PendingIntent pi = makeServicePendingIntent(context, wid); Calendar now = Calendar.getInstance(); alarm.setRepeating(AlarmManager.RTC, now.getTimeInMillis(), period, pi); Log.v(TAG, "setRepeating wid=" + wid); } } } if (intent.getAction().equals(AppWidgetManager.ACTION_APPWIDGET_DISABLED)) { // last widget removed //AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE); //alarmManager.cancel(makeServicePendingIntent(context, 0)); } if (intent.getAction().equals(AppWidgetManager.ACTION_APPWIDGET_DELETED)) { // this widget (in EXTRA_APPWIDGET_ID) deleted Bundle extras = intent.getExtras(); if (extras != null) { int wid = extras.getInt(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID); AlarmManager alarmManager = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE); alarmManager.cancel(makeServicePendingIntent(context, wid)); } } } */ private static PendingIntent makeEditorPendingIntent(Context context, int widgetId) { //return makeServicePendingIntent(context, widgetId); // run the widget editor when the intent is fired Intent intent = new Intent(context, CosmWidgetActivity.class); Settings.setWidgetId(intent, widgetId); return PendingIntent.getActivity(context, 0, intent, PendingIntent.FLAG_CANCEL_CURRENT); } public static class UpdateService extends Service { Random random = new Random(); @Override public void onStart(Intent intent, int startId) { // Deprecated start command, for pre 2.0 platforms handleStart(intent); } @Override public int onStartCommand(Intent intent, int flags, int startId) { handleStart(intent); // We want this service to continue running until it is explicitly // stopped, so return sticky. return START_STICKY; } private void handleStart(Intent intent) { Log.v(TAG, "handleStart wid=" + Settings.getWidgetId(intent)); Thread thread = new HandlerThread(intent); thread.start(); } class HandlerThread extends Thread { /* * Use a thread to perform the update, so that the * same service can be shared between several widgets * without causing delay. */ Intent intent; HandlerThread(Intent i) { intent = i; } @Override public void run() { updateWidget(intent); } } private void updateWidget(Intent intent) { // Update the widget //Log.v(TAG, "service start"); int widgetId = Settings.getWidgetId(intent); // We need to be associated with a widget // or we won't know which settings to load. if (widgetId < 0) return; // Push update for *this* widget to the home screen RemoteViews updateViews = buildUpdate(this, widgetId); AppWidgetManager manager = AppWidgetManager.getInstance(this); manager.updateAppWidget(widgetId, updateViews); //Log.v(TAG, "service end"); } private String nocache() { /* * Some service providers (especially mobile) will use a web proxy to cache * the results, so they'll give you old data. Adding a unique key to the * request should prevent this from happening. This only works if the server * doesn't mind the spurious parameter! */ return "killcache=" + random.nextInt(); } private InputStream openHttpConnection(String text, String key) throws IOException { Log.v(TAG, "url=" + text); URL url = new URL(text); URLConnection conn = url.openConnection(); HttpURLConnection http = (HttpURLConnection) conn; http.setRequestMethod("GET"); if (key != null) http.setRequestProperty("X-ApiKey", key); http.connect(); if (http.getResponseCode() == HttpURLConnection.HTTP_OK) { return http.getInputStream(); } return null; } private Bitmap getBitmapFromURL(String url) { BitmapFactory.Options options; options = new BitmapFactory.Options(); options.inSampleSize = 1; Bitmap bitmap = null; InputStream in = null; try { // Don't need the key for graphs in = openHttpConnection(url, null); if (in == null) return null; bitmap = BitmapFactory.decodeStream(in, null, options); in.close(); } catch (IOException e) { e.printStackTrace(); } return bitmap; } private String getCosmStream(String stream, JSONObject json) throws JSONException { JSONArray streams = json.getJSONArray("datastreams"); String status = json.getString("status"); if (!status.equals("live")) return status; for (int i = 0; i < streams.length(); ++i) { JSONObject st = streams.getJSONObject(i); String id = st.getString("id"); if (!id.equals(stream)) continue; String value = st.getString("current_value"); String label = ""; JSONObject units = st.getJSONObject("unit"); if (units != null) { label = units.getString("symbol"); if (label != null) value = value + " " + label; } return value; } return getString(R.string.no_stream); } private String getCurrentValues(String url, String[] streams, String key) { try { InputStream io = openHttpConnection(url, key); if (io == null) return getString(R.string.no_service); InputStreamReader is = new InputStreamReader(io); BufferedReader reader = new BufferedReader(is); String text = reader.readLine(); if (text == null) { Log.v(TAG, "no JSON data"); return getString(R.string.error); } // Concat each requested data stream's text JSONObject json = new JSONObject(text); String result = ""; for (int i = 0; i < streams.length; ++i) { String item = getCosmStream(streams[i], json); if (result.length() > 0) result += "\n"; result += item; } return result; } catch (IOException e) { ; } catch (JSONException e) { e.printStackTrace(); } return getString(R.string.no_service); } /** * Build a widget update to display Cosm Data. * Will block until the data is acquired. */ public RemoteViews buildUpdate(Context context, int widgetId) { // Build an update that holds the updated widget contents RemoteViews views = new RemoteViews(context.getPackageName(), R.layout.widget_message); // Allow the editor to be started when the widget is clicked PendingIntent pendingIntent = makeEditorPendingIntent(context, widgetId); views.setOnClickPendingIntent(R.id.widget, pendingIntent); // Fetch the persistent settings Settings s = new Settings(); s.read(this, widgetId); // TODO : make these work with any phone int width = 500; int height = 160; // convert "rrggbb" into web format String graph_colour = URLEncoder.encode("#" + s.graph_colour); String url = "http://api.cosm.com/v2/feeds/"; url += s.feed + "/datastreams/" + s.stream + ".png"; url += "?width=" + width + "&height=" + height + "&colour=" + graph_colour + "&duration=" + s.duration + "&show_axis_labels=true" + "&detailed_grid=true" + ""; // TODO : Get the timezone working properly url += "&timezone=UTC"; if (s.scale_auto) { url += "&scale=auto"; } else { url += "&scale=manual"; url += "&max=" + s.scale_max; url += "&min=" + s.scale_min; } url += "&" + nocache(); String number_text = ""; // Fetch the bitmap and display it Bitmap b = getBitmapFromURL(url); if (b == null) { // blank the screen if we can't see any data b = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565); Canvas canvas = new Canvas(b); canvas.drawColor(Color.LTGRAY); number_text = getString(R.string.bitmap_error); } views.setImageViewBitmap(R.id.image, b); // Now fetch any numeric ids. if (s.feed.length() == 0) { number_text = getString(R.string.no_feed); } else { if (s.number_ids.length() > 0) { String number_url = "http://api.cosm.com/v2/feeds/" + s.feed + ".json"; number_url += "?" + nocache(); // number ids are comma separated String[] streams = s.number_ids.split(","); number_text = getCurrentValues(number_url, streams, s.key); } } views.setTextColor(R.id.value, Color.parseColor("#" + s.number_colour)); views.setTextViewText(R.id.value, number_text); return views; } @Override public IBinder onBind(Intent intent) { // We don't need to bind to this service return null; } } }