/*** 金额输入过滤器* 1、不允许第一个字符为"."* 2、不允许出现0123、0456这类字符串* 3、保留两位小数* 4、保留小数点前面6位数(num=6)*/
class MoneyInputFilter(num: Int=6) : InputFilter {private val POINT_LENGTH = 2//保留小数点位数private var POINT_PRE_LENGTH = num//保留小数点前面位数override fun filter(source: CharSequence,//将要输入的字符串,如果是删除操作则为空start: Int,//将要输入的字符串起始下标，一般为0end: Int,//start + source字符的长度dest: Spanned,//输入之前文本框中的内容dstart: Int,//将会被替换的起始位置dend: Int//dstart+将会被替换的字符串长度): CharSequence {//方法返回的值将会替换掉dest字符串中dstartd位置到dend位置之间字符，返回source表示不做任何处理，返回空字符串""表示不输入任何字符val start = dest.subSequence(0, dstart)val end = dest.subSequence(dend, dest.length)val target = start.toString() + source + end//字符串变化后的结果val backup = dest.subSequence(dstart, dend)//将要被替换的字符串if (target.indexOf(".") == 0) {//不允许第一个字符为.return backup}if (target.startsWith("0") && !target.startsWith("0.") && "0" != target) {//不允许出现0123、0456这类字符串return backup}//限制小数点后面只能有两位小数val index = target.indexOf(".")if (index >= 0 && index + POINT_LENGTH + 2 <= target.length) {return backup}//限制小数点前面只能有6位数if (target.contains(".")) {if (target.substring(0,target.indexOf(".")).length>POINT_PRE_LENGTH){return backup}}else if (target.length > POINT_PRE_LENGTH) {return backup}return source}
}