Detecting first button in layout

I am trying to solve this conundrum: "How to get rest of the buttons in a list go under the first button."

In order to solve that issue, I have tried to set a boolean to detect the first button and apply the rule on anything below that, but button1 seems to go on top of button0 every time.

I listed the MainActivity below. The layout xml only has a Relative layout in it.

package com.code.p2_project.finalevaluationapp;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.RelativeLayout;
import java.util.ArrayList;


public class MainActivity extends Activity implements View.OnClickListener {

private ArrayList<Category> categories = new ArrayList<Category>();
private ArrayList<Button> buttons = new ArrayList<Button>();
private boolean firstButton = true;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    RelativeLayout relLayout = (RelativeLayout) findViewById(R.id.mainLayout);

    categories.add(new Category("Mobility",CategoryTypes.MOBILITY));
    categories.add(new Category("Flexibility",CategoryTypes.FLEXIBILITY));
    categories.add(new Category("Mobility",CategoryTypes.MOBILITY));
    categories.add(new Category("Flexibility",CategoryTypes.FLEXIBILITY));
    categories.add(new Category("Mobility",CategoryTypes.MOBILITY));
    categories.add(new Category("Mobility",CategoryTypes.MOBILITY));

    for (int i = 0; i < 6; i++)
    {
        makeButton(this, "Buttons"+i,i);
    }

    for (int i = 0; i < buttons.size(); i++)
    {
        addButtonToLayout(buttons.get(i),relLayout,i);
        System.out.println(buttons.get(i).getLayoutParams());
    }
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

//This method constructs a button object, sets its text, id and an OnClickListener. Finally adds the buttons to buttons arraylist
void makeButton (Context context, String buttonText, int id)
{
    Button button = new Button(context);
    button.setText(buttonText);
    button.setId(id);
    button.setOnClickListener(this);

    buttons.add(button);
    System.out.println(button.getId());
}

//Method to add button to layout. The LayoutParams are used to add the rule that the buttons should be underneath each other.
void addButtonToLayout (Button button, RelativeLayout layout, int index)
{
    RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
    RelativeLayout.LayoutParams paramsForSecondButton = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.WRAP_CONTENT);

    if (firstButton)
    {
        firstButton = false;
        System.out.println(buttons.get(index).getText());
        //TODO: [BUG] Doesn't add the first button for some reason.
    }
    else if (!firstButton)
    {
        params.addRule(RelativeLayout.BELOW, buttons.get(index-1).getId());
    }

    //paramsForSecondButton.addRule(RelativeLayout.BELOW, buttons.get(0).getId());

    //params.addRule(RelativeLayout.BELOW, buttons.get(index).getId());
    button.setLayoutParams(params);
   // buttons.get(1).setLayoutParams(paramsForSecondButton);

    layout.addView(button);
}

@Override
public void onClick(View view) {

}