Extract String key-value pairs from a JSONObject in Java?

Question

I am retrieving single rows from an SQL table as a JSONObject. They looks like this but longer:

{"UserId":1111,"FirstName":"null","LastName",:"null","City":"Dallas","State":"Select"}

I want to extract the values and place them in Android TextView fields that correspond to the keys. The null string values should to be replaced with blank space. I was unable to do this with Maps, which were the closest I've gotten to what I want. I enter them in the TextViews like so:

firstname.setText(map.get("FirstName"));

Any established approach to this problem, whether they be lists, arrays, or hashmaps, would be appreciated.

Answer 1

you can import org.json; and use JSONObject for each row

    JSONObject reader = new JSONObject(row);
    int    userId    = reader.getIn("UserId");
    String firstName    = reader.getString("FirstName");
    String lastName    = reader.getString("LastName");
    String city    = reader.getString("City");
    String state    = reader.getString("State");

Answer 2

I suggest you use Gson to map the JSON into a class:

String  jsonString = {"UserId":1111,"FirstName":"null","LastName",:"null","City":"Dallas","State":"Select"}
Row row = new Gson().fromJson(jsonString, Row.class);

Where Row.java is:

public class Row{

    @SerializedName("UserId")
    String userId;

    @SerializedName("FirstName")
    String firstName;

    @SerializedName("LastName")
    String lastName;

    @SerializedName("City")
    String city;

    @SerializedName("State")
    String state;
}

Answer 3

This is probably too late but it might be helpful to someone, you can do this

JSONObject dbJsonObj = new JSONObject(dbData);
HashMap<String, Object> map = new HashMap<>();

Iterator<String> iter = dbJsonObj.keys();
while (iter.hasNext()) {
   String key = iter.next();
   map.put(key, dbJsonObj.get(key));
}

and then

String firstName = (String) map.get("FirstName");