MobileFirst 7.1 analytics unable to capture custom messages

Hi I am new to the Mobile First analytic . I Created one Mobile First native android project and now i want to integrate analytics with that. I am mentioning code snippet using for analytics.

WLAnalytics.setContext(this); // Inside onCreate Meathod of my activity WLAnalytics.enable();

String json = "any";
try {

    WLAnalytics.log("Custom event", new JSONObject(json));


} catch (JSONException e) {
    e.printStackTrace();
}
WLAnalytics.send();

and i followed below mentioned article for that

https://developer.ibm.com/mobilefirstplatform/documentation/getting-started-6-3/moving-production/operational-analytics/

https://developer.ibm.com/mobilefirstplatform/documentation/getting-started-7-0/moving-production/operational-analytics/#clientLogs

Try this:

WLAnalytics.setContext(this);

WLAnalytics analytic = new WLAnalytics();
try {
    analytic.log("this", new JSONObject("{\"android\" : \"message\"}"));
} catch(Exception e){

}
analytic.send();

You are not creating a JSON message. My key is 'android' and my value is 'message'