app crashes

private ImageView mRefresh;
private TextView mTemperatureLabel;
private TextView mTimeLabel;
private TextView mHumidityValue;
private TextView mPrecipValue;
private TextView mSummaryLabel;
private ImageView mIconImageView;
private ProgressBar mProgressBar;
private CurrentWeather mCurrentWeather;
private Double mLatitude = 37.8267;
private Double mLongitude = -122.4233;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);


    mTemperatureLabel = (TextView)findViewById(R.id.tempratureLabel) ;
    mTimeLabel = (TextView)findViewById(R.id.timeText);
    mProgressBar = (ProgressBar) findViewById(R.id.progressBar);
    runOnUiThread(new Runnable() {
        @Override
        public void run() {
            mProgressBar.setVisibility(View.INVISIBLE);
        }
    });
    mHumidityValue =(TextView) findViewById(R.id.humidityValue);
    mPrecipValue = (TextView) findViewById(R.id.rainValue);
    mSummaryLabel = (TextView) findViewById(R.id.summaryLabel);
    mIconImageView =(ImageView) findViewById(R.id.icon);
    mRefresh = (ImageView)findViewById(R.id.refreshButton);
    mRefresh.setOnClickListener(new View.OnClickListener() {


        @Override
        public void onClick(View view) {
           getForecast(mLatitude,mLongitude);
        }
    });

    getForecast(mLatitude,mLongitude);
}

private void getForecast(Double latitude,Double longitude) {
    String secretKey = "e0acaf63d7ab893caba31a989bdeea36";

    String darkSkyUrl = "https://api.darksky.net/forecast/" + secretKey + "/" + latitude + "," + longitude;

    if (isNetworkAvailable()) {
        toggleProgressBar();
        OkHttpClient client = new OkHttpClient();
        Request request = new Request.Builder().url(darkSkyUrl).build();
        Call call = client.newCall(request);
        call.enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {

            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {

                try {
                    String jsonData = response.body().string();

                    if (response.isSuccessful()) {
                        Log.v(TAG, jsonData);
                        mCurrentWeather = getCurrentDetails(jsonData);
                        runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                setWeatherDeatils();
                                toggleProgressBar();
                            }
                        });
                    } else {
                        alertUser();
                    }
                } catch (IOException | JSONException e) {
                    Log.e(TAG, "Exception Caught: ", e);
                }
            }
        });
    } else {
        AlertDialogFragment fragment = new AlertDialogFragment(getString(R.string.no_network_message));
        fragment.show(getFragmentManager(), "network error");
    }
}

private void toggleProgressBar() {
    runOnUiThread(new Runnable() {
        @Override
        public void run() {
            if(mProgressBar.getVisibility() == View.INVISIBLE) {
                mProgressBar.setVisibility(View.VISIBLE);
                mRefresh.setVisibility(View.INVISIBLE);
            } else {
                mProgressBar.setVisibility(View.INVISIBLE);
                mRefresh.setVisibility(View.VISIBLE);
            }
        }
    });

}


private CurrentWeather getCurrentDetails(String jsonData) throws JSONException {
    JSONObject forecast = new JSONObject(jsonData);
    JSONObject currently = forecast.getJSONObject("currently");

    CurrentWeather currentWeather = new CurrentWeather();
    currentWeather.setTime(currently.getLong("time"));
    currentWeather.setIcon(currently.getString("icon"));
    currentWeather.setHumidity(currently.getDouble("humidity"));
    currentWeather.setPrecipChance(currently.getDouble("precipProbability"));
    currentWeather.setTemprature(currently.getDouble("temperature"));
    currentWeather.setSummary(currently.getString("summary"));

    return currentWeather;
}

private void setWeatherDeatils() {
    mTimeLabel.setText("At " + mCurrentWeather.getFormattedTime() + " it will be");
    mTemperatureLabel.setText(mCurrentWeather.getTemprature()+"");
    mHumidityValue.setText(mCurrentWeather.getHumidity()+"");
    mPrecipValue.setText(mCurrentWeather.getPrecipChance()+"");
    mSummaryLabel.setText(mCurrentWeather.getSummary());
    Drawable drawable = getResources().getDrawable(mCurrentWeather.getIconId());
    mIconImageView.setImageDrawable(drawable);

}


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 alertUser() {
    AlertDialogFragment fragment = new AlertDialogFragment(getString(R.string.error_message));
    fragment.show(getFragmentManager(), "error connecting");
    toggleProgressBar();
}