在smack 4.2中创建自定义节

public class CustomExtensionElement implements ExtensionElement {
    private String elementName;
    private String namespace;
    private String value;

    public CustomExtensionElement(String elementName, String namespace, String value) {
        this.elementName = elementName;
        this.namespace = namespace;
        this.value = value;
    }

    @Override
    public String getElementName() {
        return elementName;
    }

    @Override
    public String getNamespace() {
        return namespace;
    }

    @Override
    public CharSequence toXML() {
        StringBuilder sb = new StringBuilder();
        sb.append("<").append(elementName).append(" xmlns=\"").append(namespace).append("\">");
        sb.append(value);
        sb.append("</").append(elementName).append(">");
        return sb.toString();
    }
}

public class CustomExtensionProvider extends ExtensionElementProvider<CustomExtensionElement> {
    @Override
    public CustomExtensionElement parse(XmlPullParser parser, int initialDepth) throws XmlPullParserException, IOException {
        String elementName = null;
        String namespace = null;
        String value = null;

        while (true) {
            int eventType = parser.next();
            if (eventType == XmlPullParser.START_TAG) {
                if (parser.getName().equals("elementName")) {
                    elementName = parser.nextText();
                } else if (parser.getName().equals("namespace")) {
                    namespace = parser.nextText();
                } else if (parser.getName().equals("value")) {
                    value = parser.nextText();
                }
            } else if (eventType == XmlPullParser.END_TAG) {
                if (parser.getName().equals("customExtension")) {
                    break;
                }
            }
        }

        return new CustomExtensionElement(elementName, namespace, value);
    }
}

ProviderManager.addExtensionProvider("customExtension", "namespace", new CustomExtensionProvider());

CustomExtensionElement customExtension = new CustomExtensionElement("elementName", "namespace", "value");
Message message = new Message();
message.addExtension(customExtension);