java - 如何设置DocumentFilter的输入长度和范围？例如1-3 或 10-80

Question

我使用 DocumentFilter 将输入限制为整数或小数。我在这里发布的代码对此效果很好。

任何人都可以帮助我了解如何限制给定代码中的输入长度或范围吗？

谢谢!!

class MyIntFilter extends DocumentFilter {
public void insertString(FilterBypass fb, int offset, String string,
     AttributeSet attr) throws BadLocationException {

  Document doc = fb.getDocument();
  StringBuilder sb = new StringBuilder();

  sb.append(doc.getText(0, doc.getLength()));
  sb.insert(offset, string);

  if (test(sb.toString())) {
     super.insertString(fb, offset, string, attr);
  } else {
     // warn the user and don't allow the insert
  }
}

private boolean test(String text) {
  try {
     Integer.parseInt(text);
     return true;
  } catch (NumberFormatException e) {
     return false;
  }
}

@Override
public void replace(FilterBypass fb, int offset, int length, String text,
     AttributeSet attrs) throws BadLocationException {

  Document doc = fb.getDocument();
  StringBuilder sb = new StringBuilder(2);
  sb.append(doc.getText(0, doc.getLength()));
  sb.replace(offset, offset + length, text);

  if (test(sb.toString())) {
     super.replace(fb, offset, length, text, attrs);
  } else {
     // warn the user and don't allow the insert
  }

}

 @Override
 public void remove(FilterBypass fb, int offset, int length)
     throws BadLocationException {
  Document doc = fb.getDocument();
  StringBuilder sb = new StringBuilder(2);
  sb.append(doc.getText(0, doc.getLength()));
  //sb.append(doc.getText(0, 2));
  sb.delete(offset, offset + length);

  if (test(sb.toString())) {
     super.remove(fb, offset, length);
  } else {
     // warn the user and don't allow the insert
  }

}


}

Answer 1

您可能想测试一下(我没有)，但基本想法应该可以帮助您开始。

另请查看Document Filter Examples

至于设置最小长度，您可能需要使用 InputVerifier还有

class MyIntFilter extends DocumentFilter {

    private int maxLength = 0;

    public void setMaxLength(int maxLength) {
        this.maxLength = maxLength;
    }

    public int getMaxLength() {
        return maxLength;
    }

    public void insertString(FilterBypass fb, int offset, String string,
                    AttributeSet attr) throws BadLocationException {

        Document doc = fb.getDocument();
        StringBuilder sb = new StringBuilder();

        sb.append(doc.getText(0, doc.getLength()));
        sb.insert(offset, string);

        if (maxLength > 0 && doc.getLength() + string.length() <= maxLength) {
            if (test(sb.toString())) {
                super.insertString(fb, offset, string, attr);
            } else {
                // warn the user and don't allow the insert
            }
        }
    }

    private boolean test(String text) {
        try {
            Integer.parseInt(text);
            return true;
        } catch (NumberFormatException e) {
            return false;
        }
    }

    @Override
    public void replace(FilterBypass fb, int offset, int length, String text,
                    AttributeSet attrs) throws BadLocationException {

        Document doc = fb.getDocument();
        StringBuilder sb = new StringBuilder(2);
        sb.append(doc.getText(0, doc.getLength()));
        sb.replace(offset, offset + length, text);

        if (test(sb.toString())) {
            if (sb.length() > maxLength) {
                length = sb.length() - maxLength;
                if (length > 0) {
                    text = text.substring(0, length);
                    super.replace(fb, offset, length, text, attrs);
                }
            }
        } else {
            // warn the user and don't allow the insert
        }

    }

    @Override
    public void remove(FilterBypass fb, int offset, int length)
                    throws BadLocationException {
        Document doc = fb.getDocument();
        StringBuilder sb = new StringBuilder(2);
        sb.append(doc.getText(0, doc.getLength()));
        //sb.append(doc.getText(0, 2));
        sb.delete(offset, offset + length);

        if (test(sb.toString())) {
            super.remove(fb, offset, length);
        } else {
            // warn the user and don't allow the insert
        }

    }
}