限制的小数位在Android中的EditText [英] Limit Decimal Places in Android EditText

问题描述

我想编写一个应用程序，可以帮助你管理你的财务状况。我使用的是的EditText 字段，用户可以指定一笔钱。

I'm trying to write an app that helps you manage your finances. I'm using an EditText Field where the user can specify an amount of money.

我设置了​​ inputType 到 numberDecimal 这工作得很好，只是这让人们输入数字，如 123.122 这是不完美的钱。

I set the inputType to numberDecimal which works fine, except that this allows people to enter numbers such as 123.122 which is not perfect for money.

有没有办法小数点后限制字符数两个？

Is there a way to limit the number of characters after the decimal point to two?

推荐答案

本实施输入过滤的解决了这个问题。

This implementation of InputFilter solves the problem.

import android.text.SpannableStringBuilder;
import android.text.Spanned;
import android.text.method.DigitsKeyListener;

public class MoneyValueFilter extends DigitsKeyListener {
    public MoneyValueFilter() {
        super(false, true);
    }

    private int digits = 2;

    public void setDigits(int d) {
        digits = d;
    }

    @Override
    public CharSequence filter(CharSequence source, int start, int end,
            Spanned dest, int dstart, int dend) {
        CharSequence out = super.filter(source, start, end, dest, dstart, dend);

        // if changed, replace the source
        if (out != null) {
            source = out;
            start = 0;
            end = out.length();
        }

        int len = end - start;

        // if deleting, source is empty
        // and deleting can't break anything
        if (len == 0) {
            return source;
        }

        int dlen = dest.length();

        // Find the position of the decimal .
        for (int i = 0; i < dstart; i++) {
            if (dest.charAt(i) == '.') {
                // being here means, that a number has
                // been inserted after the dot
                // check if the amount of digits is right
                return (dlen-(i+1) + len > digits) ? 
                    "" :
                    new SpannableStringBuilder(source, start, end);
            }
        }

        for (int i = start; i < end; ++i) {
            if (source.charAt(i) == '.') {
                // being here means, dot has been inserted
                // check if the amount of digits is right
                if ((dlen-dend) + (end-(i + 1)) > digits)
                    return "";
                else
                    break;  // return new SpannableStringBuilder(source, start, end);
            }
        }

        // if the dot is after the inserted part,
        // nothing can break
        return new SpannableStringBuilder(source, start, end);
    }
}

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