How to call setChecked for RadioButton of specific position in RecyclerView (Adapter) java?

Question

I hope you are fine.

i need to use setChecked for RadioButton in RecyclerView Adapter, from another class, i could not do that. i hope you help me.

this is my Adapter (in this adapter all is working fine I just need to set Checked the radio button of specific position from another class, how can i do that ?):

public class Adapter extends RecyclerView.Adapter<Adapter.ViewHolder> {
    public int mSelectedItem = -1;
    public ArrayList<HashMap<String, String>> mItems;
    private Context mContext;
    public static ClickListener clickListener;

    public Adapter(Context context, ArrayList<HashMap<String, String>> items) {
        mContext = context;
        mItems = items;

    }

    @Override
    public void onBindViewHolder(Adapter.ViewHolder viewHolder, final int i) {
        View v = viewHolder.itemView;
        RadioButton radiobutton1 = v.findViewById(R.id.radiobutton1);
        radiobutton1.setChecked(i == mSelectedItem);
        RecyclerView.LayoutParams _lp = new RecyclerView.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
        v.setLayoutParams(_lp);
    }

    @Override
    public int getItemCount() {
        return mItems.size();
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
        LayoutInflater inflater = LayoutInflater.from(mContext);
        final View view = inflater.inflate(R.layout.recycler_adapter, viewGroup, false);
        return new ViewHolder(view);
    }

    class ViewHolder extends RecyclerView.ViewHolder {

        public RadioButton mRadio;
        public TextView mText;

        public ViewHolder(final View inflate) {
            super(inflate);
            mText = (TextView) inflate.findViewById(R.id.title);
            mRadio = (RadioButton) inflate.findViewById(R.id.radiobutton1);
            View.OnClickListener clickListener = new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Adapter.clickListener.onItemClick(getAdapterPosition(), v);
                    mSelectedItem = getAdapterPosition();
                    notifyDataSetChanged();
                }
            };
            itemView.setOnClickListener(clickListener);
            mRadio.setOnClickListener(clickListener);
        }
    }

    public void setOnItemClickListener(Adapter.ClickListener clickListener) {
        Adapter.clickListener = clickListener;
    }

    public interface ClickListener {
        void onItemClick(int position, View v);
    }

}

Answer 1

Here is how this is done using Java Swing (as requested by the OP)

public class RadioButtonDemo {
    
    JPanel radioPanel = null;
    
    public RadioButtonDemo() {
        RadioButtonListener listener = new RadioButtonListener();
        
        JRadioButton btnOne = new JRadioButton("One");
        JRadioButton btnTwo = new JRadioButton("Two");
        JRadioButton btnThree = new JRadioButton("Three");
        
        btnOne.addActionListener(listener);
        btnTwo.addActionListener(listener);
        btnThree.addActionListener(listener);

        btnOne.setSelected(true);
        
        ButtonGroup btnGp = new ButtonGroup();
        btnGp.add(btnOne);
        btnGp.add(btnTwo);
        btnGp.add(btnThree);
        
        radioPanel = new JPanel();
        radioPanel.add(btnOne);
        radioPanel.add(btnTwo);
        radioPanel.add(btnThree);

    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                createAndShowGui();
            }
        });
    }
    
    private static void createAndShowGui() {
        RadioButtonDemo demo = new RadioButtonDemo();
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setContentPane(demo.radioPanel);
        frame.pack();
        frame.setVisible(true);
    }
    
    private static class RadioButtonListener implements ActionListener {

        @Override
        public void actionPerformed(ActionEvent e) {
            JRadioButton btn = (JRadioButton)e.getSource();
            System.out.println("Selected button: " + btn.getText());
        }
    }
}

As you can see, I don't need to explicitly select or deselect buttons in a radio button group.