How to prevent data leak when phone stolen or sent to repair?

[acsurfer]

If your phone (needs password/fingerprint to unlock) is lost (or faulty whole screen is black/crack fully/cannot turn on and sent for repair), assuming the thief or repairman is an expert and can access the data inside, how do you prevent your data from being viewed/change?

If anyone unlocks the phone they can see the sms/whatsapp/gmail/contact list/calendar/photos...

Is there something that you can do to prevent data leak?
Is it possible like after the phone is lost/faulty, log out of all gmail and apps that are still logged in in phone and delete all photos/whatsapps/sms/contact list/calendar...

Is there anything to prevent the thief retry unlimited retry of pattern/number lock? Or set longer delay after wrong input?

Thanks.

 

[chanchan05]

If the phone has a password, the onboard data is encrypted and therefore cannot be accessed. Except for the SD card. If you didn't encrypt that, then that can be accessed.

 

[B. Diddy]

The best preventative measure is to set up a password that's hard to guess (e.g., not your birthday or your spouse's birthday or your kid's birthday). If the person who steals your phone is skilled enough to break into your phone without having to guess your password, then that person probably knows enough to get to your data regardless of what measures you take. Fortunately, there aren't that many people who are that skilled.