Android Jetpack 组合千位分隔符视觉转换，也适用于小数

您可以使用:

• 100属性使用正则表达式模式将允许的字符限制为十进制数
• 100以使用千位分隔符格式化数字

类似于:

val pattern = remember { Regex("^\\d*\\.?\\d*\$") }

TextField(
    value = text,
    onValueChange = {
        if (it.isEmpty() || it.matches(pattern)) {
            text = it
        }
    },
    keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Decimal),
    visualTransformation = ThousandSeparatorTransformation()
)

class ThousandSeparatorTransformation : VisualTransformation {
    override fun filter(text: AnnotatedString): TransformedText {

        val symbols = DecimalFormat().decimalFormatSymbols
        val decimalSeparator = symbols.decimalSeparator

        var outputText = ""
        var integerPart = 0L
        var decimalPart = ""

        if (text.text.isNotEmpty()) {
            val number = text.text.toDouble()
            integerPart = number.toLong()
            outputText += NumberFormat.getIntegerInstance().format(integerPart)
            if (text.text.contains(decimalSeparator)) {
                decimalPart = text.text.substring(text.text.indexOf(decimalSeparator))
                if (decimalPart.isNotEmpty()) {
                    outputText += decimalPart
                }
            }
        }

        val numberOffsetTranslator = object : OffsetMapping {
            override fun originalToTransformed(offset: Int): Int {
                return outputText.length
            }

            override fun transformedToOriginal(offset: Int): Int {
                return text.length
            }
        }

        return TransformedText(
            text = AnnotatedString(outputText),
            offsetMapping = numberOffsetTranslator
        )
    }
}

值为OffsetMapping时，光标在值的末尾保持不动.否则，您必须计算OffsetMapping0sSeparatorCount并根据它确定偏移量.