java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0

public static final String TAG = MainActivity.class.getSimpleName();
public static final String DAILY_FORECAST = "DAILY_FORECAST";
public static final String HOURLY_FORECAST = "HOURLY_FORECAST";



// boolean flag to toggle periodic location updates
private boolean mRequestingLocationUpdates = false;

private LocationRequest mLocationRequest;
private String currentCityName;


private Forecast mForecast;

@InjectView(R.id.timeLabel)
TextView mTimeLabel;
@InjectView(R.id.temperatureLabel)
TextView mTemperatureLabel;
@InjectView(R.id.humidityValue)
TextView mHumidityValue;
@InjectView(R.id.precipValue)
TextView mPrecipValue;
@InjectView(R.id.summaryLabel)
TextView mSummaryLabel;
@InjectView(R.id.iconImageView)
ImageView mIconImageView;
@InjectView(R.id.refreshImageView)
ImageView mRefreshImageView;
@InjectView(R.id.progressBar)
ProgressBar mProgressBar;
@InjectView(R.id.locationLabel)
TextView mLocationLabel;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    ButterKnife.inject(this);
       final double latitude ;
       final double longitude ;


    mProgressBar.setVisibility(View.INVISIBLE);

    GPSTracker GTracker = new GPSTracker(MainActivity.this);

    if (GTracker != null) {
        System.out.print("location is NOT null.... ");

        latitude = GTracker.getLatitude();
        longitude = GTracker.getLongitude();


        Geocoder geocoder = new Geocoder(this, Locale.getDefault());
        List<Address> addresses = null;
        try {
            addresses = geocoder.getFromLocation(latitude, longitude, 1);
            currentCityName = addresses.get(0).getAddressLine(2);
            //String stateName = addresses.get(0).getAddressLine(2);
            //String countryName = addresses.get(0).getAddressLine(3);
        } catch (IOException e) {
            e.printStackTrace();
        }
  } else {
        Toast.makeText(this, getString(R.string.network_unavailable_message),
               Toast.LENGTH_LONG).show();
        latitude = Double.parseDouble(null);
        longitude = Double.parseDouble(null);

    mRefreshImageView.setOnClickListener(new View.OnClickListener() {
    @Override
        public void onClick(View v) {
            getForecast(latitude, longitude);
        }
    });

  }


private void getForecast(double latitude, double longitude) {
    String apiKey = "9128496ffcbe8e4df9709ba56e90dfd4";
    String forecastUrl = "https://api.forecast.io/forecast/" + apiKey +
            "/" + latitude + "," + longitude;

    if (isNetworkAvailable()) {
        toggleRefresh();

        OkHttpClient client = new OkHttpClient();
        Request request = new Request.Builder()
                .url(forecastUrl)
                .build();

        Call call = client.newCall(request);
        call.enqueue(new Callback() {
            @Override
            public void onFailure(Request request, IOException e) {
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        toggleRefresh();
                    }
                });
                alertUserAboutError();
            }

            @Override
            public void onResponse(Response response) throws IOException {
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        toggleRefresh();
                    }
                });

                try {
                    String jsonData = response.body().string();
                    Log.v(TAG, jsonData);
                    if (response.isSuccessful()) {
                        mForecast = parseForecastDetails(jsonData);
                        runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                updateDisplay();
                            }
                        });
                    } else {
                        alertUserAboutError();
                    }
                } catch (IOException e) {
                    Log.e(TAG, "Exception caught: ", e);
                } catch (JSONException e) {
                    Log.e(TAG, "Exception caught: ", e);
                }
            }
        });
    } else {
        Toast.makeText(this, getString(R.string.network_unavailable_message),
                Toast.LENGTH_LONG).show();
    }
}

private void toggleRefresh() {
    if (mProgressBar.getVisibility() == View.INVISIBLE) {
        mProgressBar.setVisibility(View.VISIBLE);
        mRefreshImageView.setVisibility(View.INVISIBLE);
    } else {
        mProgressBar.setVisibility(View.INVISIBLE);
        mRefreshImageView.setVisibility(View.VISIBLE);
    }
}

private void updateDisplay() {
    Current current = mForecast.getCurrent();

    mTemperatureLabel.setText(current.getTemperature() + "");
    mTimeLabel.setText("At " + current.getFormattedTime() + " it will be");
    mHumidityValue.setText(current.getHumidity() + "");
    mPrecipValue.setText(current.getPrecipChance() + "%");
    mSummaryLabel.setText(current.getSummary());
    Drawable drawable = getResources().getDrawable(current.getIconId());
    mIconImageView.setImageDrawable(drawable);
    //mLocationLabel.setText(currentCityName);
}

private Forecast parseForecastDetails(String jsonData) throws JSONException {
    Forecast forecast = new Forecast();

    forecast.setCurrent(getCurrentDetails(jsonData));
    forecast.setHourlyForecast(getHourlyForecast(jsonData));
    forecast.setDailyForecast(getDailyForecast(jsonData));

    return forecast;
}

private Day[] getDailyForecast(String jsonData) throws JSONException {
    JSONObject forecast = new JSONObject(jsonData);
    String timezone = forecast.getString("timezone");
    JSONObject daily = forecast.getJSONObject("daily");
    JSONArray data = daily.getJSONArray("data");

    Day[] days = new Day[data.length()];

    for (int i = 0; i < data.length(); i++) {
        JSONObject jsonDay = data.getJSONObject(i);
        Day day = new Day();

        day.setSummary(jsonDay.getString("summary"));
        day.setIcon(jsonDay.getString("icon"));
        day.setTemperatureMax(jsonDay.getDouble("temperatureMax"));
        day.setTime(jsonDay.getLong("time"));
        day.setTimezone(timezone);

        days[i] = day;
    }

    return days;
}

private Hour[] getHourlyForecast(String jsonData) throws JSONException {
    JSONObject forecast = new JSONObject(jsonData);
    String timezone = forecast.getString("timezone");
    JSONObject hourly = forecast.getJSONObject("hourly");
    JSONArray data = hourly.getJSONArray("data");

    Hour[] hours = new Hour[data.length()];

    for (int i = 0; i < data.length(); i++) {
        JSONObject jsonHour = data.getJSONObject(i);
        Hour hour = new Hour();

        hour.setSummary(jsonHour.getString("summary"));
        hour.setIcon(jsonHour.getString("icon"));
        hour.setTemperature(jsonHour.getDouble("temperature"));
        hour.setTime(jsonHour.getLong("time"));
        hour.setTimezone(timezone);

        hours[i] = hour;
    }

    return hours;
}


private Current getCurrentDetails(String jsonData) throws JSONException {
    JSONObject forecast = new JSONObject(jsonData);
    String timezone = forecast.getString("timezone");
    Log.i(TAG, "From JSON: " + timezone);

    JSONObject currently = forecast.getJSONObject("currently");

    Current current = new Current();
    current.setHumidity(currently.getDouble("humidity"));
    current.setTime(currently.getLong("time"));
    current.setIcon(currently.getString("icon"));
    current.setPrecipChance(currently.getDouble("precipProbability"));
    current.setSummary(currently.getString("summary"));
    current.setTemperature(currently.getDouble("temperature"));
    current.setTimeZone(timezone);

    Log.d(TAG, current.getFormattedTime());

    return current;
}


private boolean isNetworkAvailable() {
    ConnectivityManager manager = (ConnectivityManager)
            getSystemService(Context.CONNECTIVITY_SERVICE);
    NetworkInfo networkInfo = manager.getActiveNetworkInfo();
    boolean isAvailable = false;
    if (networkInfo != null && networkInfo.isConnected()) {
        isAvailable = true;
    }

    return isAvailable;
}

private void alertUserAboutError() {
    alertDialogFragement dialog = new alertDialogFragement();
    dialog.show(getFragmentManager(), "error_dialog");
}

@OnClick(R.id.dailyButton)
public void startDailyActivity(View view) {
    Intent intent = new Intent(this, DailyForecastActivity.class);
    intent.putExtra(DAILY_FORECAST, mForecast.getDailyForecast());
    startActivity(intent);
}

@OnClick(R.id.hourlyButton)
public void startHourlyActivity(View view) {
    Intent intent = new Intent(this, HourlyForecastActivity.class);
    intent.putExtra(HOURLY_FORECAST, mForecast.getHourlyForecast());
    startActivity(intent);

}