Is it a good thing to write logic based on the hex value of id generated in R.java android

Question

This what I have seen in an android application. They have a number of image buttons with ids

R.java :
        public static final int img1=0x7f090080;
        p         


        

Answer 1

Though this might work OK most of the times, this is definitely not advisable. The R class is generated automatically thus you have no control over it and it could change. There is a solution to this problem using a typed array in resources. Check for example this answer.

Answer 2

You might want to use reflection.

Add this method to your code:

protected final static int getResourceID
(final String resName, final String resType, final Context ctx)
{
    final int ResourceID =
        ctx.getResources().getIdentifier(resName, resType,
            ctx.getApplicationInfo().packageName);
    if (ResourceID == 0)
    {
        throw new IllegalArgumentException
        (
            "No resource string found with name " + resName
        );
    }
    else
    {
        return ResourceID;
    }
}

And use it like this:

int myID =
    getResourceID("your_resource_name", "drawable", getApplicationContext());

Note: no path (and no extension, in case of images).