com.example.jz.mysunshine.FetchWeatherTask.java Source code

Java tutorial

Introduction

Here is the source code for com.example.jz.mysunshine.FetchWeatherTask.java

Source

package com.example.jz.mysunshine;

import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.os.AsyncTask;
import android.text.format.Time;
import android.util.Log;

import com.example.jz.mysunshine.data.WeatherContract;
import com.example.jz.mysunshine.data.WeatherContract.WeatherEntry;

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.net.HttpURLConnection;
import java.net.URL;
import java.util.Vector;
/*
 * Copyright (C) 2014 The Android Open Source Project
 *
 * 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.
 */

public class FetchWeatherTask extends AsyncTask<String, Void, Void> {

    private final String LOG_TAG = FetchWeatherTask.class.getSimpleName();
    //private final String API_KEY = "APPID";
    //private final String API_KEY_VALUE = "YOUR_API_KEY";
    private final Context mContext;

    public FetchWeatherTask(Context context) {
        mContext = context;
    }

    private boolean DEBUG = true;

    /**
     * Helper method to handle insertion of a new location in the weather database.
     *
     * @param locationSetting The location string used to request updates from the server.
     * @param cityName        A human-readable city name, e.g "Mountain View"
     * @param lat             the latitude of the city
     * @param lon             the longitude of the city
     * @return the row ID of the added location.
     */
    long addLocation(String locationSetting, String cityName, double lat, double lon) {
        long locationId;

        // First, check if the location with this city name exists in the db
        Cursor locationCursor = mContext.getContentResolver().query(WeatherContract.LocationEntry.CONTENT_URI,
                new String[] { WeatherContract.LocationEntry._ID },
                WeatherContract.LocationEntry.COLUMN_LOCATION_SETTING + " = ?", new String[] { locationSetting },
                null);

        if (locationCursor.moveToFirst()) {
            int locationIdIndex = locationCursor.getColumnIndex(WeatherContract.LocationEntry._ID);
            locationId = locationCursor.getLong(locationIdIndex);
        } else {
            // Now that the content provider is set up, inserting rows of data is pretty simple.
            // First create a ContentValues object to hold the data you want to insert.
            ContentValues locationValues = new ContentValues();

            // Then add the data, along with the corresponding name of the data type,
            // so the content provider knows what kind of value is being inserted.
            locationValues.put(WeatherContract.LocationEntry.COLUMN_CITY_NAME, cityName);
            locationValues.put(WeatherContract.LocationEntry.COLUMN_LOCATION_SETTING, locationSetting);
            locationValues.put(WeatherContract.LocationEntry.COLUMN_COORD_LAT, lat);
            locationValues.put(WeatherContract.LocationEntry.COLUMN_COORD_LONG, lon);

            // Finally, insert location data into the database.
            Uri insertedUri = mContext.getContentResolver().insert(WeatherContract.LocationEntry.CONTENT_URI,
                    locationValues);

            // The resulting URI contains the ID for the row.  Extract the locationId from the Uri.
            locationId = ContentUris.parseId(insertedUri);
        }

        locationCursor.close();
        // Wait, that worked?  Yes!
        return locationId;
    }

    /**
     * Take the String representing the complete forecast in JSON Format and
     * pull out the data we need to construct the Strings needed for the wireframes.
     * <p/>
     * Fortunately parsing is easy:  constructor takes the JSON string and converts it
     * into an Object hierarchy for us.
     */
    private void getWeatherDataFromJson(String forecastJsonStr, String locationSetting) throws JSONException {

        // Now we have a String representing the complete forecast in JSON Format.
        // Fortunately parsing is easy:  constructor takes the JSON string and converts it
        // into an Object hierarchy for us.

        // These are the names of the JSON objects that need to be extracted.

        // Location information
        final String OWM_CITY = "city";
        final String OWM_CITY_NAME = "name";
        final String OWM_COORD = "coord";

        // Location coordinate
        final String OWM_LATITUDE = "lat";
        final String OWM_LONGITUDE = "lon";

        // Weather information.  Each day's forecast info is an element of the "list" array.
        final String OWM_LIST = "list";

        final String OWM_PRESSURE = "pressure";
        final String OWM_HUMIDITY = "humidity";
        final String OWM_WINDSPEED = "speed";
        final String OWM_WIND_DIRECTION = "deg";

        // All temperatures are children of the "temp" object.
        final String OWM_TEMPERATURE = "temp";
        final String OWM_MAX = "max";
        final String OWM_MIN = "min";

        final String OWM_WEATHER = "weather";
        final String OWM_DESCRIPTION = "main";
        final String OWM_WEATHER_ID = "id";

        try {
            JSONObject forecastJson = new JSONObject(forecastJsonStr);
            JSONArray weatherArray = forecastJson.getJSONArray(OWM_LIST);

            JSONObject cityJson = forecastJson.getJSONObject(OWM_CITY);
            String cityName = cityJson.getString(OWM_CITY_NAME);

            JSONObject cityCoord = cityJson.getJSONObject(OWM_COORD);
            double cityLatitude = cityCoord.getDouble(OWM_LATITUDE);
            double cityLongitude = cityCoord.getDouble(OWM_LONGITUDE);

            long locationId = addLocation(locationSetting, cityName, cityLatitude, cityLongitude);

            // Insert the new weather information into the database
            Vector<ContentValues> cVVector = new Vector<ContentValues>(weatherArray.length());

            // OWM returns daily forecasts based upon the local time of the city that is being
            // asked for, which means that we need to know the GMT offset to translate this data
            // properly.

            // Since this data is also sent in-order and the first day is always the
            // current day, we're going to take advantage of that to get a nice
            // normalized UTC date for all of our weather.

            Time dayTime = new Time();
            dayTime.setToNow();

            // we start at the day returned by local time. Otherwise this is a mess.
            int julianStartDay = Time.getJulianDay(System.currentTimeMillis(), dayTime.gmtoff);

            // now we work exclusively in UTC
            dayTime = new Time();

            for (int i = 0; i < weatherArray.length(); i++) {
                // These are the values that will be collected.
                long dateTime;
                double pressure;
                int humidity;
                double windSpeed;
                double windDirection;

                double high;
                double low;

                String description;
                int weatherId;

                // Get the JSON object representing the day
                JSONObject dayForecast = weatherArray.getJSONObject(i);

                // Cheating to convert this to UTC time, which is what we want anyhow
                dateTime = dayTime.setJulianDay(julianStartDay + i);

                pressure = dayForecast.getDouble(OWM_PRESSURE);
                humidity = dayForecast.getInt(OWM_HUMIDITY);
                windSpeed = dayForecast.getDouble(OWM_WINDSPEED);
                windDirection = dayForecast.getDouble(OWM_WIND_DIRECTION);

                // Description is in a child array called "weather", which is 1 element long.
                // That element also contains a weather code.
                JSONObject weatherObject = dayForecast.getJSONArray(OWM_WEATHER).getJSONObject(0);
                description = weatherObject.getString(OWM_DESCRIPTION);
                weatherId = weatherObject.getInt(OWM_WEATHER_ID);

                // Temperatures are in a child object called "temp".  Try not to name variables
                // "temp" when working with temperature.  It confuses everybody.
                JSONObject temperatureObject = dayForecast.getJSONObject(OWM_TEMPERATURE);
                high = temperatureObject.getDouble(OWM_MAX);
                low = temperatureObject.getDouble(OWM_MIN);

                ContentValues weatherValues = new ContentValues();

                weatherValues.put(WeatherEntry.COLUMN_LOC_KEY, locationId);
                weatherValues.put(WeatherEntry.COLUMN_DATE, dateTime);
                weatherValues.put(WeatherEntry.COLUMN_HUMIDITY, humidity);
                weatherValues.put(WeatherEntry.COLUMN_PRESSURE, pressure);
                weatherValues.put(WeatherEntry.COLUMN_WIND_SPEED, windSpeed);
                weatherValues.put(WeatherEntry.COLUMN_DEGREES, windDirection);
                weatherValues.put(WeatherEntry.COLUMN_MAX_TEMP, high);
                weatherValues.put(WeatherEntry.COLUMN_MIN_TEMP, low);
                weatherValues.put(WeatherEntry.COLUMN_SHORT_DESC, description);
                weatherValues.put(WeatherEntry.COLUMN_WEATHER_ID, weatherId);

                cVVector.add(weatherValues);
            }
            int inserted = 0;
            // add to database
            if (cVVector.size() > 0) {
                ContentValues[] cvArray = new ContentValues[cVVector.size()];
                cVVector.toArray(cvArray);
                inserted = mContext.getContentResolver().bulkInsert(WeatherEntry.CONTENT_URI, cvArray);
            }
            Log.d(LOG_TAG, "FetchWeatherTask Complete. " + inserted + "Inserted");
        } catch (JSONException e) {
            Log.e(LOG_TAG, e.getMessage(), e);
            e.printStackTrace();
        }
    }

    @Override
    protected Void doInBackground(String... params) {

        // If there's no zip code, there's nothing to look up.  Verify size of params.
        if (params.length == 0) {
            return null;
        }
        String locationQuery = params[0];

        // These two need to be declared outside the try/catch
        // so that they can be closed in the finally block.
        HttpURLConnection urlConnection = null;
        BufferedReader reader = null;

        // Will contain the raw JSON response as a string.
        String forecastJsonStr = null;

        String format = "json";
        String units = "metric";
        int numDays = 14;

        try {
            // Construct the URL for the OpenWeatherMap query
            // Possible parameters are avaiable at OWM's forecast API page, at
            // http://openweathermap.org/API#forecast
            final String FORECAST_BASE_URL = "http://api.openweathermap.org/data/2.5/forecast/daily?";
            final String QUERY_PARAM = "q";
            final String FORMAT_PARAM = "mode";
            final String UNITS_PARAM = "units";
            final String DAYS_PARAM = "cnt";

            Uri builtUri = Uri.parse(FORECAST_BASE_URL).buildUpon().appendQueryParameter(QUERY_PARAM, params[0])
                    .appendQueryParameter(FORMAT_PARAM, format).appendQueryParameter(UNITS_PARAM, units)
                    .appendQueryParameter(DAYS_PARAM, Integer.toString(numDays))
                    //.appendQueryParameter(API_KEY,API_KEY_VALUE)
                    .build();

            URL url = new URL(builtUri.toString());

            // Create the request to OpenWeatherMap, and open the connection
            urlConnection = (HttpURLConnection) url.openConnection();

            urlConnection.setRequestMethod("GET");
            urlConnection.connect();
            // Read the input stream into a String
            InputStream inputStream;
            inputStream = urlConnection.getInputStream();
            StringBuffer buffer = new StringBuffer();
            if (inputStream == null) {
                // Nothing to do.
                return null;
            }
            reader = new BufferedReader(new InputStreamReader(inputStream));

            String line;
            while ((line = reader.readLine()) != null) {
                // Since it's JSON, adding a newline isn't necessary (it won't affect parsing)
                // But it does make debugging a *lot* easier if you print out the completed
                // buffer for debugging.
                buffer.append(line + "\n");
            }

            if (buffer.length() == 0) {
                // Stream was empty.  No point in parsing.
                return null;
            }
            forecastJsonStr = buffer.toString();
            getWeatherDataFromJson(forecastJsonStr, locationQuery);
        } catch (IOException e) {
            Log.e(LOG_TAG, "Error ", e);
            // If the code didn't successfully get the weather data, there's no point in attempting
            // to parse it.
        } catch (JSONException e) {
            Log.e(LOG_TAG, e.getMessage(), e);
            e.printStackTrace();
        } finally {
            if (urlConnection != null) {
                urlConnection.disconnect();
            }
            if (reader != null) {
                try {
                    reader.close();
                } catch (final IOException e) {
                    Log.e(LOG_TAG, "Error closing stream", e);
                }
            }
        }
        return null;
    }
}