Custom Messages

Content beyond text and images, such as an order card or shared location, can be a WKMessageContent subclass. Every client must use the same type number and JSON fields for the same content.

1. Define the content

10001 is only an example; maintain a shared registry of type numbers so product messages do not collide.

public final class OrderMessageContent extends WKMessageContent {
    public String orderID = "";
    public String title = "";

    // The SDK decodes through this no-argument constructor. Do not remove it.
    public OrderMessageContent() {
        type = 10001;
    }

    public OrderMessageContent(String orderID, String title) {
        this();
        this.orderID = orderID;
        this.title = title;
    }

    @Override
    public JSONObject encodeMsg() {
        JSONObject json = new JSONObject();
        try {
            json.put("order_id", orderID);
            json.put("title", title);
        } catch (JSONException ignored) {
        }
        return json;
    }

    @Override
    public WKMessageContent decodeMsg(JSONObject json) {
        orderID = json.optString("order_id", "");
        title = json.optString("title", "");
        return this;
    }

    @Override public String getDisplayContent() {
        return "[Order] " + title;
    }

    @Override public String getSearchableWord() {
        return title;
    }
}

If this content crosses Android component boundaries through Parcel, also implement the subclass parcel constructor, writeToParcel, and CREATOR, following the built-in SDK content types.

2. Register after initialization

WKIM.getInstance().init(applicationContext, uid, token);
WKIM.getInstance().getMsgManager()
    .registerContentMsg(OrderMessageContent.class);

Register before connecting or reading messages. The class must have a public no-argument constructor so the SDK can decode it.

3. Send and render

OrderMessageContent content =
    new OrderMessageContent("order-2026-001", "Coffee beans");
WKChannel channel = new WKChannel("bob", WKChannelType.PERSONAL);
WKIM.getInstance().getMsgManager().send(content, channel);

Inspect the runtime type when receiving, and show a generic placeholder for unknown content:

if (message.baseContentMsgModel instanceof OrderMessageContent) {
    OrderMessageContent order =
        (OrderMessageContent) message.baseContentMsgModel;
    showOrder(order.orderID, order.title);
} else {
    showUnsupportedMessage();
}

Give new fields defaults, do not reuse old fields for new meanings, and never change a published type number.

Android Custom Messages

1. Define the content

2. Register after initialization

3. Send and render

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