TextInputEditText count the entered character as 2 characters

Question

TextInputEditText has a limit on the maximum number of characters entered, for example 30. It is necessary that when you enter the @ character, it counts as 2, i.e. if you enter only @, then you can enter no more than 15 characters. How to implement such an algorithm?

Answer 1

solution found, function together with textChanges() RxJava

fun charDoubleLength(string:String, charDouble: Char, editText: EditText, maxLengthLine: Int){
        val charCount = string.filter { char ->
            char == charDouble
        }.count()
        val maxLengthEditText= maxLengthLine - charCount
        editText.filters =
            arrayOf<InputFilter>(InputFilter.LengthFilter(maxLengthEditText))
    }