In android studio with java How to load web text as string from an activity for Android 6+ devices

From an Activity, How can I retrieve code or text from a website and display to the user ? I'm having difficulties programming back to Android, now developing as for Android 6.0 and newer. Getting deprecated about http client etc.. so I need a little of help.

Can you paste me some code example including "imports" in order to when the app load, from an Activity class, and also when a user click a "button1", to retrieve the text displayed from a web say "yahoo.es", and show a message to the user with the text from the web (loaded and parsed to a string) using Toast.

Help much appreciated in advance