Use WEB_URL pattern in Patterns Class
It will return True if URL is valid and false if URL is invalid.
As of Android API level 8 there is a WEB_URL pattern. Quoting the source, it “match[es] most part of RFC 3987”. If you target a lower API level you could simply copy the pattern from the source and include it in your application. I assume you know how to use patterns and matchers, so I’m not going into more details here.
Also the class URLUtil provides some useful methods, e.g:
The descriptions of the methods are not very elaborate, therefore you are probably best of looking at the source and figuring out which one fits your purpose best.
As for when to trigger the validation check, there are multiple possibilities: you could use the EditText callback functions
or use a TextWatcher, which I think would be better.
DON’T USE URLUtil to validate the URL as below.
because it gives strings like “http://” as valid URL which isn’t true