java - DecimalFormat java允许在点后输入0

Question

我有一个 DecimalFormat ，其模式如下 "#,###.###"但是，当我想输入例如 50.05 时，它不允许这样做，因为每次文本更改以及调用

时，我都会将字符串解析为数字

df.parse("50.0");

它返回50.并剪切0

有什么办法可以输入像 50.05 这样的数字吗？

我的类(class)的完整代码如下所示。抱歉，如果太冗长:

private class NumberTextWatcher implements TextWatcher {
    @SuppressWarnings("unused")
    private static final String TAG = "NumberTextWatcher";

    private DecimalFormat df;
    private DecimalFormat dfnd;
    private boolean hasFractionalPart;

    private EditText et;

    NumberTextWatcher(EditText et) {
        df = (DecimalFormat) DecimalFormat.getInstance(Locale.ENGLISH);
        df.applyLocalizedPattern(hasThousandSeparator ? "#,###.###" : "####.###");
        df.setDecimalSeparatorAlwaysShown(true);
        df.setMaximumFractionDigits(maxDecimal);
        dfnd = (DecimalFormat) DecimalFormat.getInstance(Locale.ENGLISH);
        dfnd.applyLocalizedPattern(hasThousandSeparator ? "#,###" : "####");
        dfnd.setMaximumFractionDigits(maxDecimal);
        this.et = et;
        hasFractionalPart = false;
    }

    @Override
    public void afterTextChanged(Editable s) {
        et.removeTextChangedListener(this);

        try {
            int inilen, endlen;
            inilen = et.getText().length();

            String sign = hasSign ? s.toString().startsWith("-") ? "-" : "+" : null;
            String sStr = hasSignAttached(s) ? s.toString().substring(1) : s.toString();

            String v = sStr.replace(String.valueOf(df.getDecimalFormatSymbols().getGroupingSeparator()), "");

            if(v.length() == 0){
                return;
            }

            if(hasFractionalPart){
                String[] vSplit = v.split("\\.");

                String intStr = vSplit[0];
                String decStr = vSplit.length > 1 ? vSplit[1] : "";

                if(intStr.length() > maxNumbers)
                    intStr = intStr.substring(0, maxNumbers);

                if(decStr.length() > maxDecimal)
                    decStr = decStr.substring(0, maxDecimal);

                v = String.format("%s.%s", intStr, decStr);
            } else {
                if(v.length() > maxNumbers)
                    v = v.substring(0, maxNumbers);
            }


            Number n = df.parse(v);
            int cp = et.getSelectionStart();

            String formatted;

            if (hasFractionalPart) {
                formatted = df.format(n);
            } else {
                formatted = dfnd.format(n);
            }

            et.setText(hasSign ? String.format("%s%s", sign, formatted) : formatted);

            endlen = et.getText().length();
            int sel = (cp + (endlen - inilen));
            if (sel > 0 && sel <= et.getText().length()) {
                et.setSelection(sel);
            } else {
                // place cursor at the end?
                et.setSelection(et.getText().length() - 1);
            }

        } catch (Exception e) {
            ExceptionTracker.trackException(e);
        } finally {
            et.addTextChangedListener(this);
        }
    }

    private boolean hasSignAttached(Editable s){
        return s.toString().startsWith("+") || s.toString().startsWith("-");
    }

    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
        if(hasSign && start == 1 && count == 1){
            et.setText("");
        }
    }

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        hasFractionalPart = s.toString().contains(String.valueOf(df.getDecimalFormatSymbols().getDecimalSeparator()));
    }
}

Answer 1

此代码解决了问题:

import java.text.DecimalFormat;

public class DecimalFormatExample {

    public static void main(String[] args) {

    DecimalFormat dformat = new DecimalFormat("#,###.###");
    dformat.setMinimumFractionDigits(1);

    String someNumber = "50.05";
    Double someNumberDouble = Double.valueOf(someNumber);
    System.out.println(dformat.format(someNumberDouble));  // 50.05

    someNumber = "50.0";
    someNumberDouble = Double.valueOf(someNumber);
    System.out.println(dformat.format(someNumberDouble));  // 50.0

    }
}