EditTextView 限制輸入

public class NumberInputFilter implements InputFilter {
    /**
     * 最大數(shù)字
     */
    public double MAX_VALUE = 9999999;
    /**
     * 最小數(shù)
     */
    public double MIN_VALUE = 0;
    /**
     * 小數(shù)點(diǎn)后的數(shù)字的位數(shù)
     */
    public int POINTER_LENGTH = 2;

    private static final String POINTER = ".";

    Pattern p;

    public NumberInputFilter() {
        //用于匹配輸入的是0-9  .  這幾個(gè)數(shù)字和字符
        p = Pattern.compile("([0-9]|\\.)*");
    }

    /**
     * @param max    最大數(shù)
     * @param length 小數(shù)點(diǎn)位數(shù)
     */
    public NumberInputFilter(double max, int length) {
        MAX_VALUE = max;
        POINTER_LENGTH = length;
        //用于匹配輸入的是0-9  .  這幾個(gè)數(shù)字和字符
        p = Pattern.compile("([0-9]|\\.)*");
    }

    /**
     * @param max    最大數(shù)
     * @param min    最小數(shù)(length=0時(shí)生效)
     * @param length 小數(shù)點(diǎn)位數(shù)
     */
    public NumberInputFilter(double max, double min, int length) {
        MAX_VALUE = max;
        MIN_VALUE = min;
        POINTER_LENGTH = length;
        if (length == 0) {
            //用于匹配輸入的是0-9  .  這幾個(gè)數(shù)字和字符
            p = Pattern.compile("([0-9])*");
        } else {
            p = Pattern.compile("([0-9]|\\.)*");
        }
    }


    /**
     * source    新輸入的字符串
     * start    新輸入的字符串起始下標(biāo)，一般為0
     * end    新輸入的字符串終點(diǎn)下標(biāo)臣嚣，一般為source長(zhǎng)度-1
     * dest    輸入之前文本框內(nèi)容
     * dstart    原內(nèi)容起始坐標(biāo)，一般為0
     * dend    原內(nèi)容終點(diǎn)坐標(biāo)，一般為dest長(zhǎng)度-1
     */

    @Override
    public CharSequence filter(CharSequence source, int start, int end,
                               Spanned dest, int dstart, int dend) {
        //驗(yàn)證刪除等按鍵
        if (TextUtils.isEmpty(source)) {
            return "";
        }
        Matcher matcher = p.matcher(source);
        if (!matcher.matches()) {
            return "";
        }
        //已經(jīng)輸入小數(shù)點(diǎn)的情況下谓着，只能輸入數(shù)字
        if (dest.toString().contains(POINTER)) {
            if (POINTER.contentEquals(source)) { //只能輸入一個(gè)小數(shù)點(diǎn)
                return "";
            }
            //驗(yàn)證小數(shù)點(diǎn)精度，保證小數(shù)點(diǎn)后只能輸入多少位
            int index = dest.toString().indexOf(POINTER);
            int length = dest.toString().substring(index).length();
            // dstart > index 輸入位置在原點(diǎn)之后途凫，
            if (dstart > index && length == POINTER_LENGTH + 1) {
                return "";
            }
        } else {
            //限制小數(shù)點(diǎn)位數(shù)
            if (POINTER_LENGTH > 0) {
                if (source.equals(POINTER) && dest.toString().length() == 0) {
                    return "0.";
                }
            } else {
                if (source.equals(POINTER)) {
                    return "";
                }
            }
        }
        //限制大小
        String inputStr = dest.toString().substring(0, dstart) + source + dest.toString().substring(dstart, dest.length());
        double input = Double.parseDouble(inputStr);
        if (isInRange(MIN_VALUE, MAX_VALUE, input)) {
            return null;
        } else {
            if (POINTER_LENGTH > 0 && (inputStr.equals("0.0") || inputStr.equals("0.00"))) { // 忽略0.0 0.00等情況
                return null;
            }
        }
        return "";
    }

    private boolean isInRange(double a, double b, double c) {
        return b > a ? c >= a && c <= b : c >= b && c <= a;
    }
}