Regular Expression In Android for Password Field

Question

How can i validating the EditText with Regex by allowing particular characters . My condition is :

Password Rule:

1. On

Answer 1

And for the Kotlin lovers :

fun isValidPassword(password: String?) : Boolean {
   password?.let {
       val passwordPattern = "^(?=.*[0-9])(?=.*[a-z])(?=.*[A-Z])(?=.*[@#$%^&+=])(?=\\S+$).{4,}$"
       val passwordMatcher = Regex(passwordPattern)

       return passwordMatcher.find(password) != null
   } ?: return false
}