Android convert Arabic number to English Number

More generic solution using Character.getNumericValue(char)

static String replaceNonstandardDigits(String input) {
    if (input == null || input.isEmpty()) {
        return input;
    }

    StringBuilder builder = new StringBuilder();
    for (int i = 0; i < input.length(); i++) {
        char ch = input.charAt(i);
        if (isNonstandardDigit(ch)) {
            int numericValue = Character.getNumericValue(ch);
            if (numericValue >= 0) {
                builder.append(numericValue);
            }
        } else {
            builder.append(ch);
        }
    }
    return builder.toString();
}

private static boolean isNonstandardDigit(char ch) {
    return Character.isDigit(ch) && !(ch >= '0' && ch <= '9');
}

Try this:

String number = arabicToDecimal("۴۲"); // number = 42;

private static final String arabic = "\u06f0\u06f1\u06f2\u06f3\u06f4\u06f5\u06f6\u06f7\u06f8\u06f9";
private static String arabicToDecimal(String number) {
    char[] chars = new char[number.length()];
    for(int i=0;i<number.length();i++) {
        char ch = number.charAt(i);
        if (ch >= 0x0660 && ch <= 0x0669)
           ch -= 0x0660 - '0';
        else if (ch >= 0x06f0 && ch <= 0x06F9)
           ch -= 0x06f0 - '0';
        chars[i] = ch;
    }
    return new String(chars);
}

A modified generic solution

    fun convertArabic(arabicStr: String): String? {
        val chArr = arabicStr.toCharArray()
        val sb = StringBuilder()
        for (ch in chArr) {
            if (Character.isDigit(ch)) {
                sb.append(Character.getNumericValue(ch))
            }else if (ch == '٫'){
                sb.append(".")
            }

            else {
                sb.append(ch)
            }
        }
        return sb.toString()
    }

The second branch is necessary as double numbers has this character as dot separator '٫'

Kotlin developers:

fun ArabicToEnglish(str: String):String {
        var result = ""
        var en = '0'
        for (ch in str) {
            en = ch
            when (ch) {
                '۰' -> en = '0'
                '۱' -> en = '1'
                '۲' -> en = '2'
                '۳' -> en = '3'
                '۴' -> en = '4'
                '۵' -> en = '5'
                '۶' -> en = '6'
                '۷' -> en = '7'
                '۸' -> en = '8'
                '۹' -> en = '9'
            }
            result = "${result}$en"
        }
        return result
    }