[JavaForFun] /

package com.weather.information.fragment.map;

import java.io.IOException;
import java.util.List;
import java.util.Locale;

import android.app.Activity;
import android.content.Context;
import android.location.Address;
import android.location.Geocoder;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.weather.information.R;
import com.weather.information.model.WeatherLocation;

/**
 * {@link http://www.androiddesignpatterns.com/2013/04/retaining-objects-across-config-changes.html}
 *
 */
public class MapProgressFragment extends Fragment {

        /**
         * 
         * Callback interface through which the fragment will report the
         * task's progress and results back to the Activity.
         */
        public static interface TaskCallbacks {
                void onPostExecute(final WeatherLocation weatherLocation);
        }
        
        private TaskCallbacks mCallbacks;
        
    @Override
    public View onCreateView(final LayoutInflater inflater, final ViewGroup container,
                             final Bundle savedInstanceState) {
    
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.weather_map_progress, container, false);
    }
    
    /**
     * This method will only be called once when the retained
     * Fragment is first created.
     */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        
        // Retain this fragment across configuration changes.
        this.setRetainInstance(true);
        
        final Bundle bundle = this.getArguments();
        double latitude = bundle.getDouble("latitude");
        double longitude = bundle.getDouble("longitude");
        
        // Create and execute the background task.
        new GetAddressTask(this.getActivity().getApplicationContext()).execute(latitude, longitude);
    }
    
        /**
         * Hold a reference to the parent Activity so we can report the
         * task's current progress and results. The Android framework 
         * will pass us a reference to the newly created Activity after 
         * each configuration change.
         */
        @Override
        public void onAttach(final Activity activity) {
                super.onAttach(activity);
                mCallbacks = (TaskCallbacks) activity;
        }
        
        /**
         * Set the callback to null so we don't accidentally leak the 
         * Activity instance.
         */
//      @Override
//      public void onDetach() {
//              super.onDetach();
//              mCallbacks = null;
//      }
        
        /**
         * I am not using onDetach because there are problems when my activity goes to background.
         * 
         * {@link http://www.androiddesignpatterns.com/2013/08/fragment-transaction-commit-state-loss.html}
         */
        @Override
        public void onPause() {
                super.onPause();
                mCallbacks = null;
        }
    
    private class GetAddressTask extends AsyncTask<Object, Void, WeatherLocation> {
        private static final String TAG = "GetAddressTask";
        // Store the context passed to the AsyncTask when the system instantiates it.
        private final Context localContext;

        private GetAddressTask(final Context context) {
                this.localContext = context;    
        }
        
        @Override
        protected WeatherLocation doInBackground(final Object... params) {
            final double latitude = (Double) params[0];
            final double longitude = (Double) params[1];

            WeatherLocation weatherLocation = this.doDefaultLocation(latitude, longitude);
            try {
                weatherLocation = this.getLocation(latitude, longitude);
            } catch (final Throwable e) { // Hopefully nothing goes wrong because of catching Throwable.
                Log.e(TAG, "GetAddressTask doInBackground exception: ", e);
            }

            return weatherLocation;
        }

        @Override
        protected void onPostExecute(final WeatherLocation weatherLocation) {
 
            // Call updateUI on the UI thread.
                if (mCallbacks != null) {
                        mCallbacks.onPostExecute(weatherLocation);
                }
        }
        
        private WeatherLocation getLocation(final double latitude, final double longitude) throws IOException {
                // TODO: i18n Locale.getDefault()
            final Geocoder geocoder = new Geocoder(this.localContext, Locale.US);
            final List<Address> addresses = geocoder.getFromLocation(latitude, longitude, 1);

            // Default values
            WeatherLocation weatherLocation = this.doDefaultLocation(latitude, longitude);
            
            if (addresses != null && addresses.size() > 0) {
                if (addresses.get(0).getLocality() != null) {
                        weatherLocation.setCity(addresses.get(0).getLocality());
                }
                if(addresses.get(0).getCountryName() != null) {
                        weatherLocation.setCountry(addresses.get(0).getCountryName());
                }       
            }

            return weatherLocation;
        }

        private WeatherLocation doDefaultLocation(final double latitude, final double longitude) {
                // Default values
            String city = this.localContext.getString(R.string.city_not_found);
            String country = this.localContext.getString(R.string.country_not_found);

            return new WeatherLocation()
                        .setLatitude(latitude)
                        .setLongitude(longitude)
                        .setCity(city)
                        .setCountry(country);
        }
    }
}