Magento 2: Make changes to default.xml programmatically

Question

I was wondering if it's possible to make changes to default.xml programmatically?

Use case is as follows:

• I want a different theme being loaded when a certain mode is activated for example by clicking on a checkbox.
• Or should I use a different approach?

Answer 1

I guess you want to change theme basic of some condition.

Then, Do the below steps:

• A dropdown on which each option will have URL mode respective theme id at its URL.URL will be like http//www.example.com/{frontenName}/{ControllerName}/{ActionName}/mode/{RespectivethemeCode}

• Now at Action, you need to fetch mode parameter value and save the mode value to a Session Variable.

• Last at controller dispatch event change theme based on the mode session variable.