Get Android resource value from any class

Question

I'm just starting with Android programming and I'm still a little confused with some concepts. I'll tell you what I'm trying to do using a simplified example:

I'm retrieving a list of cars from a remote server (PHP/MySQL/JSON) and showing them on a ListView.

This is the server response JSON structure:

{
    error: null,
    data: {
        cars: [
            {name: "Lamborghini Diablo", color_id: 1},
            {name: "McLaren F1", color_id: 2},
            {name: "Ferrari F355", color_id: 1}
        ]
    }
}

Then I wrote the Car class:

public class Car {

    public String name;
    public int color_id;
    public String color_name;

    public Car(JSONObject data) {
        try {
            this.name = data.getString("name");
            this.color_id = data.getInt("color_id");
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }
}

And last, this is a piece of the strings.xml resource file:

<string-array name="color_names">
    <item>White</item>
    <item>Yellow</item>
    <item>Orange</item>
    <item>Red</item>
    <item>Black</item>
</string-array>

When I get the data from server, there is a for loop to create the instances of the Car class, one for each item in the JSONArray .

What I want to do is to get the color name from the <string-array> , using the property color_id as the array index, but I can't find a way to get the R.array resource from the Car class constructor.

How should I do this?

Thank You!

Answer 1

What I want to do is to get the color name from the , using the property color_id as the array index, but I can't find a way to get the R.array resource from the Car class constructor.

Your class has to know "about Context" since resources are available only from Context , so here you need a little modification in your constructor:

public Car(Context c, JSONObject data) {
   // do your stuff
}

Now, your class knows current Context so you're able to obtain data you need:

String name = c.getResources().getStringArray(R.id.arrayId)[<index>];

Hope it'll solve your problem.

Answer 2

You should provide context ot Car object or instantiate array from res in some util class with app context and provide API something like Utils.getColorNameByColorId(int color_id) . The last way is preferable because of performance - array will be instantiate only once.