Logcat doesn’t prevent app crashes. It just logs the all system messages/warnings/errors about everything in your device. So you can learn what’s going wrong for your app.
Logcat is a command-line tool that dumps a log of system messages, including stack traces when the device throws an error and messages.
Logcat command-line tool | Android Studio | Android Developers
This tutorial can help you:
https://forum.xda-developers.com/showthread.php?t=1726238