Question

I’ve searched Google and this website many times, but can not find a solution to my question.

First, I understand, you can load images using something like:

int image = R.drawable.icon; (assuming there's a file called 'icon.png')

and I’ve read about, and tried using:

getResources().getIdentifier("resname", "restype", com.example.whatever);

But, here’s what I’m unable to do:
I want to be able to have pictures in the /res/drawable folder (I believe that’s the correct folder), WITHOUT KNOWING ANY OF THE NAMES OF THE FILES, and load them dynamically – at run-time.

One (of the many) things I’ve tried is (something like):

int[] images = new int[numberOfImages];
for( 0 to numberOfImages )
{
    images[i] = 
        getResources().getIdentifier("resname", "restype", com.example.whatever);
}

This returns 0 EVERY TIME, so it’s not going to work

I’d like to get the name and integer identifier for every picture in the /res/drawables folder. Can this be done WITHOUT KNOWING ANY FILE NAMES?

———————————————————————-

[adding this after the question was resolved to help anyone that may run into the same issue in the future. It just shows that it does in fact work.]

    Class resources = R.drawable.class;
    Field[] fields = resources.getFields();
    String[] imageName = new String[fields.length];     
    int index = 0;
    for( Field field : fields )
    {
        imageName[index] = field.getName();
        index++;
    }

    int result = 
            getResources().getIdentifier(imageName[10], "drawable", "com.example.name");

Answer 1

Well, if you have to do it, use reflection 🙂

Class resources = R.drawable.class;
Field[] fields = resources.getFields();
for (Field field : fields) {
    System.out.println(field.getName());
}

However, in a way, you are still hard-coding stuff, since you will only be putting a fixed set of drawables in your app. 🙂