IOS: Data to JSON object

The encapsulated conversion method directly passes in the data you need to convert-(NSString *) Getjsonfromdata: (ID) sender{    //json object    nsstring *jsonstr;    Convert the incoming data to the    nsdata *jsondata = [nsjsonserialization datawithjsonobject:sender options: Nsjsonwritingprettyprinted Error:nil];    Data security Judgment    if (jsondata) {        jsonstr = [[NSString alloc] Initwithdata:jsondata encoding:nsutf8stringencoding];    } else{        NSLog (@ "Get data is nil");    return JSONSTR;}

IOS: Data to JSON object