Android Loading ProgressDialog

public class LoadingHelper {

    private static ProgressDialog progress;

    public void run(Context context, final CallbackInterface callback){
        progress = ProgressDialog.show(context, "Carregando",
                "Por favor, aguarde :D", true);

        new Thread(new Runnable() {
            @Override
            public void run()
            {
                if(callback != null)
                    callback.run();
            }
        }).start();
    }

    public static void dismiss(){
        progress.dismiss();
    }


    public interface CallbackInterface
    {
        public void run ();
    }
}

Então para exibir o ProgressDialog:

LoadingHelper.run(context, null);

// Ou usando a função de callback

LoadingHelper.run(context, new CallbackInterface(){

@Override
void run(){
    
}

});

Para esconder o ProgressDialog:

LoadingHelper.dismiss();