Format credit card in edit text in android

Question

How to make EditText accept input in format:

4digit 4digit 4digit 4digit 

I tried Custom format edit text input android to acc

Answer 1

None of above answers is perfect for me. I created one that solves the start-string/end-string/mid-string issues. Copy & Paste should also work fine. This supports Mastercard, Visa and Amex. You can change the separator. If you don't need payment method type just remove it. It is Kotlin though. The idea is simple. Everytime when text changed I remove all separators and re-added them base on the format. The solves the issue start-string/mid-string issues. Then the only problem is that you need to work out the the right text position after separators added.

fun addCreditCardNumberTxtWatcher(et: EditText, separator: Char, paymentMethodType: PaymentMethodType): TextWatcher {
    val tw = object : TextWatcher {
        var mBlock = false
        override fun afterTextChanged(s: Editable) {
        }
        override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, after: Int) {
              Logger.d("_debug", "s: $s, start: $start, count: $count, after $after")
        }
        override fun onTextChanged(s: CharSequence?, start: Int, before: Int, count: Int) {
            if (mBlock)
                return
            var lastPos = et.selectionStart
            val oldStr = et.text.toString().replace(separator.toString(), "", false)
            var newFormattedStr = ""
            if (before > 0) {
                if (lastPos > 0 && et.text.toString()[lastPos - 1] == separator) lastPos--
            }
            Logger.d("_debug", "lastPos: $lastPos, s: $s, start: $start, before: $before, count $count")
            mBlock = true
            oldStr.forEachIndexed { i, c ->
                when (paymentMethodType) {
                    PaymentMethodType.MASTERCARD, PaymentMethodType.VISA -> {
                        if (i > 0 && i % 4 == 0) {
                            newFormattedStr += separator
                        }
                    }
                    PaymentMethodType.AMERICAN_EXPRESS -> {
                        if (i == 4 || i == 10 || i == 15) {
                            newFormattedStr += separator
                        }
                    }
                }
                newFormattedStr += c
            }
            et.setText(newFormattedStr)
            if (before == 0) {
                if (et.text.toString()[lastPos - 1] == separator) lastPos++
            }
            et.setSelection(lastPos)
            mBlock = false
        }
    }
    et.addTextChangedListener(tw)
    return tw
}