Get Android resource ID from string in an adapter

Issue

I'm trying to get Android resource ID and set ImageView src to that specific ID from a JSON array.

I'm using the following code

String str = mDataset.get(position).icon_res.substring(0, mDataset.get(position).icon_res.lastIndexOf('.'));
        int res = Resources.getSystem().getIdentifier("ic_" + str, "drawable", this.getClass().getPackage().getName());
        if(res == 0)
        {
            Log.d("is null", "null");
            Log.d("string = ", "ic_" + str);
            Log.d("package", this.getClass().getPackage().getName());
        }

But from some reason it's detecting the res int as 0. Package name seems correct, string is correct but for some reason it's not finding the correct drawable resource. What am I doing wrong here?

EDIT:

Full adapter code

package com.xyz

import android.app.Activity;
import android.app.Application;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.drawable.Drawable;
import android.media.Image;
import android.support.constraint.ConstraintLayout;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by Kreso on 23.3.2017..
 */

public class CategoryAdapter extends RecyclerView.Adapter<CategoryAdapter.ViewHolder>{


    private List<Category> mDataset;
    private Context context;

    public CategoryAdapter(List<Category> categoriesList) {
        mDataset = categoriesList;
    }


    // Provide a reference to the views for each data item
    // Complex data items may need more than one view per item, and
    // you provide access to all the views for a data item in a view holder
    public class ViewHolder extends RecyclerView.ViewHolder {
        // each data item is just a string in this case
        public TextView txtHeader;
        public ConstraintLayout holderLayout;
        public ImageView icon;

        public ViewHolder(View v) {
            super(v);
            txtHeader = (TextView) v.findViewById(R.id.firstLine);
            holderLayout = (ConstraintLayout) v.findViewById(R.id.itemHolder);
            icon = (ImageView) v.findViewById(R.id.icon);
            context = v.getContext();
        }
    }

    /*public void add(int position, String item) {
        mDataset.add(position, item);
        notifyItemInserted(position);
    }*/

    public void remove(int position) {
        mDataset.remove(position);
        notifyItemRemoved(position);
        notifyItemRangeChanged(position, mDataset.size());
    }

    // Provide a suitable constructor (depends on the kind of dataset)
   /* public CategoryAdapter(ArrayList<String> myDataset) {
        mDataset = myDataset;
    }*/

    // Create new views (invoked by the layout manager)
    @Override
    public CategoryAdapter.ViewHolder onCreateViewHolder(ViewGroup parent,
                                                   int viewType) {
        // create a new view
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycler_item_row, parent, false);
        // set the view's size, margins, paddings and layout parameters
        ViewHolder vh = new ViewHolder(v);
        return vh;
    }

    // Replace the contents of a view (invoked by the layout manager)
    @Override
    public void onBindViewHolder(ViewHolder holder, final int position) {
        // - get element from your dataset at this position
        // - replace the contents of the view with that element
    final String name = mDataset.get(position).name;
        holder.txtHeader.setText(mDataset.get(position).name);
        //holder.icon.setImageResource(R.drawable.ic_beer);
        String str = mDataset.get(position).icon_res.substring(0, mDataset.get(position).icon_res.lastIndexOf('.'));
        int res = context.getResources().getSystem().getIdentifier("ic_" + str, "drawable", context.getPackageName());
        if(res == 0)
        {
            Log.d("is null", "null");
            Log.d("string = ", "ic_" + str);
            Log.d("package", this.getClass().getPackage().getName());
        }

        holder.icon.setImageResource(res);
        holder.holderLayout.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            remove(position);
        }
    });

}

    // Return the size of your dataset (invoked by the layout manager)
    @Override
    public int getItemCount() {
        return mDataset.size();
    }

}

Solution

use this code, to get image from Resources :

int res = context.getResources().getIdentifier("ic_" + str, "drawable", context.getPackageName());

Answered By - Narendra Sorathiya