Android: Shall I have access to resources from my own class?

I my project I have a class that in this class I want to have access to properties of a picture. But I don't want to show it through this class. In this class I just want to know width and height of image and do some mathematical functions to return something.

My problem is I can't have access to resources. for example, when I write

image = BitmapFactory.decodeResource(this.getResources(), R.drawable.tasnim);

It says the method getResources() in undefined for the type Stego (stego is my class name).

Please tell me what should I do?

public class Stego()
{
    Public Stego(){
     开发者_如何学编程   image = BitmapFactory.decodeResource(this.getResources(), R.drawable.tasnim);
        imWidth  = image.getWidth();
        imHeight = image.getHeight();
    }
}

The getResources() function belongs to the Context class. So unless your Stego class directly (or indirectly) extends Context, there is no getResources() function available.

So what you need to do is pass along a reference to your application's context (e.g. in the constructor of your Stego class or similar). Or if all you need is a single resource ID it might be easier to just pass along that ID.

This could for instance look like this:

public class Stego()
{
    Public Stego(Context myAppContext){
        image = BitmapFactory.decodeResource(myAppContext.getResources(), R.drawable.tasnim);
        imWidth  = image.getWidth();
        imHeight = image.getHeight();
    }
}

From your activity you can then initialize an instance of your Stego class like this:

Stego stego = new Stego(this);