How can i change the theme at runtime and set it as default

Currently, we are using Appzillon 3.5.3 in which we use apz.changeStyleTheme(theme) to change the theme everytime a user login to the app. We are doing device binding of the registered user with the device, for the same purpose we want a method using which we can set the default theme for registered user whose userID is binded with the devices to show personalized theme. Which method can i use to set the theme name in property file?
1) For saving the theme details in the device ,it can be acheived by storing in the application preference storage which will be stored in the application sandbox.
- setPref plugin can be used to store the value. This value will be present in the device until user clears the app data.
2) On launch of the application on the first page check for the preferences if the theme is present so it can be loaded using the apz.changeStyleTheme(theme) function where the theme name should be passed to the function.
- getPref plugin can be used to retrive the value.