[Q] way to analyze code of app to see if it is malicious? topic

I want to download and install the IP Webcam app from the Play store. Even though it has over 5 million installs, how would I be able to tell that it wasn't doing something malicious like allowing backdoor entry to my network or transmitting snapshots back to the developer or someone else? If I want to use it as a security camera...how can I be sure that it is not doing something behind the scenes?