（3）解析 API 响应

Edamam API 返回的响应是 JSON 格式，我们需要解析它。

import org.json.JSONException;
import org.json.JSONObject;
import okhttp3.Response;

public class NutritionData {
    private double calories;
    private double protein;
    private double fat;
    private double carbs;

    public NutritionData(double calories, double protein, double fat, double carbs) {
        this.calories = calories;
        this.protein = protein;
        this.fat = fat;
        this.carbs = carbs;
    }

    public static NutritionData fromJson(Response response) throws IOException, JSONException {
        String jsonData = response.body().string();
        JSONObject json = new JSONObject(jsonData);

        JSONObject totalNutrients = json.getJSONObject("totalNutrients");
        double calories = json.optDouble("calories", 0);
        double protein = totalNutrients.getJSONObject("PROCNT").optDouble("quantity", 0);
        double fat = totalNutrients.getJSONObject("FAT").optDouble("quantity", 0);
        double carbs = totalNutrients.getJSONObject("CHOCDF").optDouble("quantity", 0);

        return new NutritionData(calories, protein, fat, carbs);
    }

    @Override
    public String toString() {
        return String.format("Calories: %.2f kcal\nProtein: %.2f g\nFat: %.2f g\nCarbs: %.2f g", calories, protein, fat, carbs);
    }
}