no. it does not work.
Whenever I change the HTTP to HTTPS on /wp-admin/options-general.php. The website looks messed up.
Now what I need to do is to just adjust my theme first right ? change the http to https in the theme. because it was coded with http.
I also can't access WP-Admin when it is directed to HTTPS
_az
42
It isn't. You have to explicitly set the HTTPS variable in Apache - there's no implicit parsing of x-forwarded-proto.
So WordPress thinks it's never in HTTPS mode and loops pointlessly.
SetEnvIf is valid to put in a lot of places. For example, you can put it directly inside your <VirtualHost>.
9peppe
43
THANK YOU so much. it worked.
But some contents are not showing. Need some little adjusment.

_az
45
Super! As I mentioned before, https://www.whynopadlock.com can be a valuable tool to identify the resources which are not being loaded.
Thank you @9peppe for the help too. forgive me for being so stupid. 
9peppe
47
Don’t worry about it, we all can be impatient from time to time.