Android Open Source - Sunshine Forecast Fragment

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License

The source code is released under:

MIT License

Java Source Code

package me.kalehv.t.sunshine;
//from  w  w  w  .  j  a v a 2 s. c  o m
/**
 * Created by harshadkale on 7/17/14.
 */

import android.app.LauncherActivity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

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.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.List;

/**
 * Encapsulates fetching the forecast and displaying it as a {@link ListView} layout.
 */
public class ForecastFragment extends Fragment
{

    private ArrayAdapter<String> mForecastAdapter;

    public ForecastFragment()
    {
    }

    @Override
    public void onStart()
    {
        super.onStart();
        updateWeather();
    }

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        // Add this line in order for this fragment to handle menu events.
        setHasOptionsMenu(true);
    }

    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater)
    {
        inflater.inflate(R.menu.forecastfragment, menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item)
    {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.

        switch (item.getItemId())
        {
            case R.id.action_refresh:
                updateWeather();
                return true;
        }

        return super.onOptionsItemSelected(item);
    }

    private void updateWeather()
    {
        FetchWeatherTask weatherTask = new FetchWeatherTask();

        SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(getActivity());
        String locationKey = getActivity().getResources().getString(R.string.pref_location_key);
        String locationDefVal = getActivity().getResources().getString(R.string.pref_location_default);
        String location = preferences.getString(locationKey, locationDefVal);

        weatherTask.execute(location);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState)
    {

        // Create some dummy data for the ListView.  Here's a sample weekly forecast
        String[] data = {};
        List<String> weekForecast = new ArrayList<String>(Arrays.asList(data));

        // Now that we have some dummy forecast data, create an ArrayAdapter.
        // The ArrayAdapter will take data from a source (like our dummy forecast) and
        // use it to populate the ListView it's attached to.
        mForecastAdapter =
                new ArrayAdapter<String>(
                        getActivity(), // The current context (this activity)
                        R.layout.list_item_forecast, // The name of the layout ID.
                        R.id.list_item_forecast_textview, // The ID of the textview to populate.
                        weekForecast);

        View rootView = inflater.inflate(R.layout.fragment_main, container, false);

        // Get a reference to the ListView, and attach this adapter to it.
        ListView listView = (ListView) rootView.findViewById(R.id.listview_forecast);
        listView.setAdapter(mForecastAdapter);

        listView.setOnItemClickListener(new AdapterView.OnItemClickListener()
        {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id)
            {
                String forecast = mForecastAdapter.getItem(position);
                Intent intent = new Intent(getActivity(), DetailActivity.class);
                intent.putExtra(Intent.EXTRA_TEXT, forecast);
                startActivity(intent);
            }
        });

        return rootView;
    }

    public class FetchWeatherTask extends AsyncTask<String, Void, String[]>
    {
        private final String LOG_TAG = FetchWeatherTask.class.getSimpleName();

        /**
         * The date/time conversion code is going to be moved outside the asynctask later,
         * so for convenience we're breaking it out into its own method now.
         */
        private String getReadableDateString(long time)
        {
            // Because the API returns a unix timestamp (measured in seconds),
            // it must be converted to milliseconds in order to be converted to valid date.
            Date date = new Date(time * 1000);
            SimpleDateFormat format = new SimpleDateFormat("E, MMM d");
            return format.format(date).toString();
        }

        /**
         * Prepare the weather high/lows for presentation.
         */
        private String formatHighLows(double high, double low)
        {
            // For presentation, assume the user doesn't care about tenths of a degree.
            long roundedHigh = Math.round(high);
            long roundedLow = Math.round(low);

            String highLowStr = roundedHigh + "/" + roundedLow;
            return highLowStr;
        }

        private double convertTemperatureToAppropriateUnit(double temperature)
        {
            SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getActivity());

            String unitKey = getActivity().getResources().getString(R.string.pref_unit_key);
            String temperatureUnitDefVal = getActivity().getResources().getString(R.string.pref_unit_default);
            String temperatureUnit = sharedPreferences.getString(unitKey, temperatureUnitDefVal);

            if (temperatureUnit.equalsIgnoreCase(getActivity().getResources().getString(R.string.pref_unit_default)))
            {
                return temperature;
            }

            return ((temperature - 32.0) * (5.0 / 9.0));
        }

        /**
         * 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 String[] getWeatherDataFromJson(String forecastJsonStr, int numDays)
                throws JSONException
        {

            // These are the names of the JSON objects that need to be extracted.
            final String OWM_LIST = "list";
            final String OWM_WEATHER = "weather";
            final String OWM_TEMPERATURE = "temp";
            final String OWM_MAX = "max";
            final String OWM_MIN = "min";
            final String OWM_DATETIME = "dt";
            final String OWM_DESCRIPTION = "main";

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

            String[] resultStrs = new String[numDays];
            for (int i = 0; i < weatherArray.length(); i++)
            {
                // For now, using the format "Day, description, hi/low"
                String day;
                String description;
                String highAndLow;

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

                // The date/time is returned as a long.  We need to convert that
                // into something human-readable, since most people won't read "1400356800" as
                // "this saturday".
                long dateTime = dayForecast.getLong(OWM_DATETIME);
                day = getReadableDateString(dateTime);

                // description is in a child array called "weather", which is 1 element long.
                JSONObject weatherObject = dayForecast.getJSONArray(OWM_WEATHER).getJSONObject(0);
                description = weatherObject.getString(OWM_DESCRIPTION);

                // 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);
                double high = convertTemperatureToAppropriateUnit(temperatureObject.getDouble(OWM_MAX));
                double low = convertTemperatureToAppropriateUnit(temperatureObject.getDouble(OWM_MIN));

                highAndLow = formatHighLows(high, low);
                resultStrs[i] = day + " - " + description + " - " + highAndLow;
            }

            for (String s : resultStrs)
            {
                Log.v(LOG_TAG, "Forecast entry: " + s);
            }
            return resultStrs;

        }

        @Override
        protected String[] 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;
            }

            // 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 = PreferenceManager.getDefaultSharedPreferences(getActivity())
                                            .getString(getResources().getString(R.string.pref_unit_default),
                                             getResources().getString(R.string.pref_unit_default));
            int numDays = 7;

            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))
                        .build();

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

                Log.v(LOG_TAG, "Built URI " + 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 = 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();

                Log.v(LOG_TAG, "Forecast string: " + forecastJsonStr);
            }
            catch (IOException e)
            {
                Log.e(LOG_TAG, "Error ", e);
                // If the code didn't successfully get the weather data, there's no point in attemping
                // to parse it.
                return null;
            }
            finally
            {
                if (urlConnection != null)
                {
                    urlConnection.disconnect();
                }
                if (reader != null)
                {
                    try
                    {
                        reader.close();
                    }
                    catch (final IOException e)
                    {
                        Log.e(LOG_TAG, "Error closing stream", e);
                    }
                }
            }

            try
            {
                return getWeatherDataFromJson(forecastJsonStr, numDays);
            }
            catch (JSONException e)
            {
                Log.e(LOG_TAG, e.getMessage(), e);
                e.printStackTrace();
            }

            // This will only happen if there was an error getting or parsing the forecast.
            return null;
        }

        @Override
        protected void onPostExecute(String[] result)
        {
            if (result != null)
            {
                mForecastAdapter.clear();
                for (String dayForecastStr : result)
                {
                    mForecastAdapter.add(dayForecastStr);
                }
                // New data is back from the server.  Hooray!
            }
        }
    }
}

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