Can you change backgroundcolor of an layout resource in Android Studio?

I have an activity with a button "Select color" and a edittxt (insert hex code for color). When user hit the button the backgroundcolor of the resourcefile must change to hex code. The color is now set on XML file. How can I change this XML file with user input?

package com.gade.tabletcolor;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.graphics.Color;
import android.graphics.PorterDuff;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.Toast;

public class PickColor extends AppCompatActivity {

    View view;
    EditText addColor;

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

        ImageButton button = findViewById(R.id.imageBtn11);
        Button AddColor = findViewById(R.id.colorBtn);
        addColor = findViewById(R.id.txtColor);
        view = this.getWindow().getDecorView();

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                nextpage();
            }
        });

        AddColor.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                setContentView(R.layout.pickcolor);


            }
        });

    }

    public void nextpage(){
        Intent intent = new Intent(this,MainActivity.class);
        startActivity(intent);
    }
}