Question

我需要在NumberFormat的NumberConstants中更改NaN值和减号。 “动态”更改NumberConstants是不可能的，所以我决定将NumberFormat子类化。

NumberFormat的构造函数注释说：

@param numberConstants要使用的特定于语言环境的数字常量这种格式 - 注意子类在这里传递自己的实例应该注意{@link #forcedLatinDigits（）}并重新映射使用{@link #createLatinNumberConstants（NumberConstants）}
的本地化符号

在我要执行的方法createLatinNumberConstants（NumberConstants）中，我应该调用setForcedLatinDigits（true）。然后，本地化的常量将由（createLatinNumberConstants）方法更新，我将得到我需要的NumberConstants。

这是我的代码：

public class MyNumberFormat extends NumberFormat {
      protected MyNumberFormat(String pattern, CurrencyData cdata, boolean userSuppliedPattern) {
        this(defaul, pattern, cdata, userSuppliedPattern);
    }

      protected MyNumberFormat(NumberConstants numberConstants, String pattern, CurrencyData cdata, boolean userSuppliedPattern) {
        super(numberConstants, pattern, cdata, userSuppliedPattern);
    }

      public static MyNumberFormat getFormat(String pattern) {
        return  new MyNumberFormat(pattern, CurrencyList.get().getDefault(), true);
    }

      protected static NumberConstants createLatinNumberConstants(
            final NumberConstants orig) {
        final String groupingSeparator = remapSeparator(
                orig.groupingSeparator());
        final String decimalSeparator = remapSeparator(
                orig.decimalSeparator());
        final String monetaryGroupingSeparator = remapSeparator(
                orig.monetaryGroupingSeparator());
        final String monetarySeparator = remapSeparator(
                orig.monetarySeparator());
        return new NumberConstants() {
            @Override
            public String currencyPattern() {
                return orig.currencyPattern();
            }

            @Override
            public String decimalPattern() {
                return orig.decimalPattern();
            }

            @Override
            public String decimalSeparator() {
                return decimalSeparator;
            }

            @Override
            public String defCurrencyCode() {
                return orig.defCurrencyCode();
            }

            @Override
            public String exponentialSymbol() {
                return orig.exponentialSymbol();
            }

            @Override
            public String globalCurrencyPattern() {
                return orig.globalCurrencyPattern();
            }

            @Override
            public String groupingSeparator() {
                return groupingSeparator;
            }

            @Override
            public String infinity() {
                return orig.infinity();
            }

            @Override
            public String minusSign() {
                return UnicodeSymbols.MINUS;
            }

            @Override
            public String monetaryGroupingSeparator() {
                return monetaryGroupingSeparator;
            }

            @Override
            public String monetarySeparator() {
                return monetarySeparator;
            }

            @Override
            public String notANumber() {
                return "?";
            }

            @Override
            public String percent() {
                return orig.percent();
            }

            @Override
            public String percentPattern() {
                return orig.percentPattern();
            }

            @Override
            public String perMill() {
                return orig.perMill();
            }

            @Override
            public String plusSign() {
                return orig.plusSign();
            }

            @Override
            public String scientificPattern() {
                return orig.scientificPattern();
            }

            @Override
            public String simpleCurrencyPattern() {
                return orig.simpleCurrencyPattern();
            }

            @Override
            public String zeroDigit() {
                return "0";
            }
        };
    }
  }

因此，为了格式化数字，我将执行此操作：

String fmt(final Double x){
      MyNumberFormat.setForcedLatinDigits(true);
      MyNumberFormat format = MyNumberFormat.getFormat("0.0000");
      return format.format(x)
   }

但实际上createLatinNumberConstants是受保护的静态方法，它不能被覆盖或替换。所以永远不会执行MyNumberFormat.createLatinNumberConstants（）。

我做错了什么？

Answer 1

我认为你不需要覆盖createLatinNumberConstants - 而是将你的数字常量传递给超类的构造函数。作为基础，您可以使用NumberFormat的默认数字常量。

这样的事情应该有效：

public class MyNumberFormat extends NumberFormat {
    protected MyNumberFormat(String pattern, CurrencyData cdata, boolean userSuppliedPattern) {
      super(createMyNumberConstants(NumberFormat.defaultNumberConstants), pattern, cdata, userSuppliedPattern);
  }

    public static MyNumberFormat getFormat(String pattern) {
      return new MyNumberFormat(pattern, CurrencyList.get().getDefault(), true);
  }

protected static final NumberConstants createMyNumberConstants(
      final NumberConstants orig) {
  return new NumberConstants() {
      @Override
      public String currencyPattern() {
          return orig.currencyPattern();
      }

      @Override
      public String decimalPattern() {
          return orig.decimalPattern();
      }

      @Override
      public String decimalSeparator() {
          return decimalSeparator();
      }

      @Override
      public String defCurrencyCode() {
          return orig.defCurrencyCode();
      }

      @Override
      public String exponentialSymbol() {
          return orig.exponentialSymbol();
      }

      @Override
      public String globalCurrencyPattern() {
          return orig.globalCurrencyPattern();
      }

      @Override
      public String groupingSeparator() {
          return orig.groupingSeparator();
      }

      @Override
      public String infinity() {
          return orig.infinity();
      }

      @Override
      public String minusSign() {
          return orig.minusSign();
      }

      @Override
      public String monetaryGroupingSeparator() {
          return orig.monetaryGroupingSeparator();
      }

      @Override
      public String monetarySeparator() {
          return orig.monetarySeparator();
      }

      @Override
      public String notANumber() {
          return "?";
      }

      @Override
      public String percent() {
          return orig.percent();
      }

      @Override
      public String percentPattern() {
          return orig.percentPattern();
      }

      @Override
      public String perMill() {
          return orig.perMill();
      }

      @Override
      public String plusSign() {
          return orig.plusSign();
      }

      @Override
      public String scientificPattern() {
          return orig.scientificPattern();
      }

      @Override
      public String simpleCurrencyPattern() {
          return orig.simpleCurrencyPattern();
      }

      @Override
      public String zeroDigit() {
          return "0";
      }
  };

}

GWT - 如何更改NumberFormat

1 个答案: