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Android Build a Weather App (2015) Working with JSON Setting CurrentWeather from JSON

Posted by Ali Ahmed
Ali Ahmed
53 Points

How to change the degree to Celsius?

Hi I just want to know in the "Stormy App" How I can change the temperature in which file of the project? Thanks

1 Answer

Steve Hunter
Steve Hunter
57,712 Points

Hi Ali,

The temperature is held in the CurrentWeather class instance called currentWeather. There's a getter method that returns the value provided by the JSON data. At the moment, that's in Fahrenheit; you want a conversion to Celsius, I assume?

At the moment, the method is:

public int getTemperature() {
   return (int)Math.round(mTemperature);
}

So, you need to tinker with mTemperature before it is returned. Converting from F to C involves subtracting 32, then multiplying the result by 5/9. (I think!!)

So, something like:

public int getTemperature() {
   return (int)Math.round((mTemperature -32) * (5/9));
}

That might do the trick. I hope that helps and works!!

Steve.

ammonquackenbush
ammonquackenbush
3,867 Points

Good idea.

Brendan Milton
Brendan Milton
9,050 Points
Brendan Milton
Brendan Milton
9,050 Points

Hi Steve!

I read over your info on converting from F to C, Im just struggling with how to use the method in the current weather program? would it be used in conjunction with one of the following lines of code?

ie: "current.setTemperature(currently.getDouble("temperature"));" Towards the bottom?

  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;
    }
Steve Hunter
Steve Hunter
57,712 Points

Hi Brendan Milton

I implemented the conversion in the class definition. So, inside the Class definition for, say, Current, I have:

public class Current {
  .
  .
  .
  private double mTemperature;
  .
  .
  .

  public int getTemperature() {
    double celsius = (mTemperature - 32.0) * 0.5555;
    return (int)Math.round(celsius);
  }
}

I have the same in the Hour class. Within the Day class, I applied the maths within the getTemperatureMax() method.

Yes, you can use fewer lines of code just return the calculation, but I prefer the more verbose approach as it makes the calculation clearer, for me.

I hope that makes sense.

Steve.