I have this Json statement :
{name=Adam Schmidt, id=43}
and I want to extract the value of the name,
trying this code but it didn't work
// parse json data
try {
JSONObject userObject = new JSONObject(result);
userName = userObject.getString("name");
tvName.setText(userName);
} catch (Exception ex) {
ex.printStackTrace();
}
You statement is not valid json. Here's the sample of valid json.
{\"name\":\"Adam Schmidt\", \"id\":43}
Update:
For number value, no quotation mark
Use GSON. Super easy.
Declare a class that represents your JSON structure:
public class Person {
private String name;
private int id;
public String getName() {
return name;
}
public int getId() {
return id;
}
}
Then you can do:
String json = "{\"name\":\"Adam Schmidt\", \"id\":43}";
String userName = new Gson().fromJson(json, Person.class).getName();
tvName.setText(userName);
This is much better than haphazardly parsing chunks with various get methods all over your code. Plus you get a nice object to pass around and use in your object oriented code.
Related
I am pretty weak with JSON, and probably have a silly question, and was wondering how to parse a JSON object placed inside a JSON array.
So, as of now, I have
public Single<Profile> doProfileApiCall() {
return Rx2AndroidNetworking.post(ApiEndPoint.ENDPOINT_PROFILE)
.addHeaders(mApiHeader.getProtectedApiHeader())
.build()
.getObjectSingle(Profile.class);
To retrieve my profile params, but in my endpoints I have :
[{"Name": "this", "Email","that#gmail.com"}]
I have my endpoint set up as :
public static final String ENDPOINT_PROFILE =
BuildConfig.BASE_URL
+ "/linktojson";
which gives me the above JSON.
but the issue is the [], how do I modify this with :
public Single<Profile> doProfileApiCall() {
return Rx2AndroidNetworking.post(ApiEndPoint.ENDPOINT_PROFILE)
.addHeaders(mApiHeader.getProtectedApiHeader())
.build()
.getObjectSingle(Profile.class);
such that I can use my profile.java model class which has
public class Profile {
#Expose
#SerializedName("Name")
private String name;
#Expose
#SerializedName("Email")
private String email;
etc...
}
Any idea how to go about this?
In the doProfileApiCall() method instead of .getObjectSingle use
.getJSONArraySingle(ProfileList.class)
Now create a new class ProfileList.java with the following code.
List<Profile> profileList = new ArrayList<>();
public List<Profile> getProfileList() {
return profileList;
}
public void setProfileList(List<Profile> profileList) {
this.profileList = profileList;
}
Change the returntype of the doProfileApiCall method to
public Single<ProfileList> doProfileApiCall()
Whenever you want to access the data use it with the list position 0, when in future you get more data, you can index the data accordingly.
Generally, if JSON root object is an array you should use List on Java side. In your case you have array so use related method:
return Rx2AndroidNetworking.post(ApiEndPoint.ENDPOINT_PROFILE)
.addHeaders(mApiHeader.getProtectedApiHeader())
.build()
.getObjectListSingle(Profile.class);
Rx2ANRequest source.
I have a nested JSON array from which I need to retrieve values of all Usernames nested within Friends.
{
"Friends": [
{"Username": "abc"},
{"Username": "xyz"}
]
}
After I get all the usernames, I want to store it in a List that I will use with an adapter and ListView.
FriendList.java:
public class FriendList
{
#SerializedName("Username")
private String username;
public String getUsername()
{
return username;
}
public void setUsername(String username)
{
this.username = username;
}
}
This is the code that I have written so far:
if (httpResult != null && !httpResult.isEmpty()) //POST API CALL
{
Type listType = new TypeToken<List<FriendList>>() {}.getType();
List<FriendList> friendList = new Gson().fromJson(httpResult, listType);
FLCustomAdapter adapter = new FLCustomAdapter(getActivity(), friendList);
mainFriendsListView.setAdapter(adapter);
}
However, an error occurs: Failed to deserialize Json object.
Please suggest, what additions/changes should be made to it, so that I can retrieve nested JSON values into a list?
First of all, You have to understand the strucure of this Json.
You can see, it contains
1 . A json object
2 . This json object contains a json array which can include several different json objects or json arrays.
In this case, it contains json objects.
Parsing:
Get the Json Object first
try{
JSONObject jsonObject=new JSONObject(jsonResponse);
if(jsonObject!=null){
//get the json array
JSONArray jsonArray=jsonObject.getJSONArray("Friends");
if(jsonArray!=null){
ArrayList<FriendList> friendList=new ArrayList<FriendList>();
//iterate your json array
for(int i=0;i<jsonArray.length();i++){
JSONObject object=jsonArray.getJSONObject(i);
FriendList friend=new FriendList();
friend.setUserName(object.getString(Username));
friendList.add(friend);
}
}
}
}
catch(JSONException ex){
ex.printStackTrace();
}
hope, it will help you.
Solution with GSON.
You need to two class to parse this.
FriendList and UsernameDao.
public class UsernameDao {
#SerializedName("Username")
private String username;
//get set methods
}
Simple Json Parsing would be like this
JSONObject params=new JSONObject(httpResult);
JSONObject params1=params.getJsonObject("Friends");
JsonArray array=params1.getJsonArray();
for(int i=0;i<array.length();i++)
{
String userName=array.getJsonObject(i).getString("UserName");
// Do whatever you want to do with username
}
Following code works good without any use of GSON , Please try .
String jsonString = "Your Json Data";
JSONObject jsonRootObject = new JSONObject(jsonString );
JSONArray friendsArray = jsonRootObject .getJSONArray("Friends");
ArrayList<FriendList > friendsList = new ArrayList<FriendList >();
for(int friendsLen = 0 ;friendsLen < friendsArray .length() ; friendsLen ++){
FriendList userNameObj = new UserName();
JSONObject jsonObj = jsonRootObject.getJSONObject(friendsLen ) ;
String Username = jsonObj.getString("Username");
userNameObj .setUserName(Username );
friendsList .add(userNameObj );
}
Now friendsList the list which you want .
List<FriendList> friendList = new Gson().fromJson(httpResult, listType);
This cannot work because it expects your whole JSON document to be just an array of FriendList element (by the way, why "FriendList"?): [{"Username": "abc"},{"Username": "xyz"}] -- this is what can be parsed by your approach.
The easiest solution to fix this (apart from harder to implement but more efficient streamed reading in order to peel of possible unnecessary properties) is just creating a correct mapping:
final class Wrapper {
#SerializedName("Friends")
final List<Friend> friends = null;
}
final class Friend {
#SerializedName("Username")
final String username = null;
}
Now deserialization is trivial and you don't have to define a type token because Gson has enough information for the type from the Wrapper.friends field:
final Wrapper wrapper = gson.fromJson(response, Wrapper.class);
for ( final Friend friend : wrapper.friends ) {
System.out.println(friend.username);
}
Output:
abc
xyz
Change List<FriendList> friendList = new Gson().fromJson(httpResult, listType);
to
FriendList friends = new Gson().fromJson(httpResult, listType);
List<Friend> friends = friends.list;
Updated FriendList.java as mentioned below
FriendList.java
public class FriendList
{
#SerializedName("Friends")
public List<Friend> list;
}
Friend.java
public class Friend
{
#SerializedName("Username")
private String username;
public String getUsername()
{
return username;
}
public void setUsername(String username)
{
this.username = username;
}
}
I have a JSON file that is being parsed with Gson. The problem I have is there are nested arrays in the Json e.g.
"assets":[
{
"Address":"Crator1, The Moon",
"Title":"The Moon",
"AudioFile":null,
"Categories":[
{
"CategoryName":"Restaurants",
"Description":"blah blah",
"ExternalLink":"",
"File":"",
"FileName":"0",
"CategoryID":0,
"ParentCategoryID":786,
"Id":334,
"Image":"",
},
I know it's invalid, it's just for an example. So based on previous questions I have asked and research I believe I should have my code as follows in order to parse the JSON correctly:
public class JsonAssets implements Parcelable{
String Address;
String Title;
String AudioFile;
Categories[] categories;
private class Categories{
String CategoryName;
String Description;
String ExternalLink;
String File;
String FileName;
int CategoryID;
int ParentCategoryID;
int Id;
String Image;
}
}
The class is passed as follows:
JsonReader reader = new JsonReader(new InputStreamReader(is, "UTF-8"));
reader.beginObject();
reader.nextName();
reader.beginArray();
JsonObject obj = null;
while (reader.hasNext()) {
try{
switch(type){
case ASSET_UPDATE:
obj = gson.fromJson(reader, JsonAsset.class);
break;
}
So I read and write the address, audio file as so:
public static final Parcelable.Creator<AssetJson> CREATOR = new Parcelable.Creator<AssetJson>() {
public AssetJson createFromParcel(Parcel in) {
return new AssetJson(in);
}
public AssetJson[] newArray(int size) {
return new AssetJson[size];
}
};
public void writeToParcel(Parcel paramParcel, int paramInt) {
paramParcel.writeString(Address);
paramParcel.writeString(Title);
paramParcel.writeString(AudioFile);
}
private JsonAsset(Parcel in) {
Address = in.readString();
Title = in.readString();
AudioFile = in.readString();
}
The problem I have is I don't know how to read and write Categories[] to the parcel. The fact that it is an object array has me stumped.
This is my first experience with parcelables and I'm trying to take over someone elses code. So if anyone could explain how I would parcel an object array, I'd greatly appreciate it.
Thank you!
Simple, first make your Category class implement Parcelable, implement all the logic for reading and writing back there, then use Parcel class writeParcelableArray method to write an array of parcelables.
Hope this help.
I managed to find the correct solution (for me) so if anyone else is coming up against this, follow this link:
http://www.javacreed.com/gson-deserialiser-example/
It shows how to parse nested array and deserialize.
i have a problem getting timestamp(rowversion) from my SQL Azure database.
In my tables there is a column with datatype timestamp. This timestamp isn't similar to datetime, it's more like a rowversion.
I can get all other data in this table with the query from MobileServiceTable, there is no problem.
But this special datatype is a problem.
My class for this table looks like:
public class ArbeitsgangBezeichnung {
#com.google.gson.annotations.SerializedName("id")
private int ID;
#com.google.gson.annotations.SerializedName("ABZ_ArbeitsgangBezeichnungID")
private int ABZ_ArbeitsgangBezeichnungID;
#com.google.gson.annotations.SerializedName("ABZ_Bezeichnung")
private String ABZ_Bezeichnung;
#com.google.gson.annotations.SerializedName("ABZ_RowVersion")
private StringMap<Number> ABZ_RowVersion;
//constructor, getter, setter, etc....
}
If i login in Azure and look at the table, there are my example values and the automatic generated timestamp. The timestamp value looks like "AAAAAAAAB/M=". If i login in sql database and let me show the data, then for timestamp there is only "binarydata" (in pointed brackets) and not that value as it is shown in Azure.
The variable "ABZ_RowVersion" should include this timestamp, but the data in the StringMap doesn't look like the one in Azure. I tried String and Byte as datatype for the StringMap, but it doesn't helped.
I tried byte[] for ABZ_RowVersion, but then i got an exception in the callback method.
Then i tried Object for ABZ_RowVersion, that time i found out, that it is a StringMap, but nothing more.
Does anybody know, how to get the data from timestamp, i need it for comparison.
Thanks already
When you create a timestamp column in a table, it's essentially a varbinary(8) column. In the node SQL driver, it's mapped to a Buffer type (the usual node.js type used for binary data). The object which you see ({"0":0, "1":0, ..., "length":8}) is the way that a buffer is stringified into JSON. That representation doesn't map to the default byte array representation from the Gson serializer in Android (or to the byte[] in the managed code).
To be able to use timestamp columns, the first thing you need to do is to "teach" the serializer how to understand the format of the column returned by the server. You can do that with a JsonDeserializer<byte[]> class:
public class ByteArrayFromNodeBufferGsonSerializer
implements JsonDeserializer<byte[]> {
#Override
public byte[] deserialize(JsonElement element, Type type,
JsonDeserializationContext context) throws JsonParseException {
if (element == null || element.isJsonNull()) {
return null;
} else {
JsonObject jo = element.getAsJsonObject();
int len = jo.get("length").getAsInt();
byte[] result = new byte[len];
for (int i = 0; i < len; i++) {
String key = Integer.toString(i);
result[i] = jo.get(key).getAsByte();
}
return result;
}
}
}
Now you should be able to read data. There's still another problem, though. On insert and update operations, the value of the column is sent by the client, and SQL doesn't let you set them in them. So let's take this class:
public class Test {
#SerializedName("id")
private int mId;
#SerializedName("name")
private String mName;
#SerializedName("version")
private byte[] mVersion;
public int getId() { return mId; }
public void setId(int id) { this.mId = id; }
public String getName() { return mName; }
public void setName(String name) { this.mName = name; }
public byte[] getVersion() { return mVersion; }
public void setVersion(byte[] version) { this.mVersion = version; }
}
On the insert and update operations, the first thing we need to do in the server-side script is to remove that property from the object. And there's another issue: after the insert is done, the runtime doesn't return the rowversion property (i.e., it doesn't update the item variable. So we need to perform a lookup against the DB to retrieve that column as well:
function insert(item, user, request) {
delete item.version;
request.execute({
success: function() {
tables.current.lookup(item.id, {
success: function(inserted) {
request.respond(201, inserted);
}
});
}
});
}
And the same on update:
function update(item, user, request) {
delete item.version;
request.execute({
success: function() {
tables.current.lookup(item.id, {
success: function(updated) {
request.respond(200, updated);
}
});
}
});
}
Now, this definitely is a lot of work - the support for this type of column should be better. I've created a feature request in the UserVoice page at http://mobileservices.uservoice.com/forums/182281-feature-requests/suggestions/4670504-better-support-for-timestamp-columns, so feel free to vote it up to help the team prioritize it.
i want to analyse the json just like:
[{"id":"ssq","name":"双色球","term":"2010092","date":"2010-08-12 19:15","numbers":{"normal":"3,13,19,27,28,30","special":"2"},"jackpot":"30000000"},{"id":"3d","name":"3D","term":"2010216","date":"2010-08-12 19:55","numbers":{"normal":"6,8,8"},"jackpot":"-"},{"id":"qlc","name":"七乐彩","term":"2010093","date":"2010-08-11 20:45","numbers":{"normal":"08,09,10,11,16,21,27","special":"26"},"jackpot":"0"},{"id":"dfljy","name":"东方6+1","term":"2010093","date":"2010-08-14 18:30","numbers":{"normal":"4,1,3,9,7,2","special":"羊"},"jackpot":"12866531"},{"id":"swxw","name":"15选5","term":"2010217","date":"2010-08-12 18:45","numbers":{"normal":"1,3,5,13,15"},"jackpot":"5693612"},{"id":"ssl","name":"时时乐","term":"20100811-23","date":"2010-08-12 10:27","numbers":{"normal":"6,7,1"},"jackpot":"-"},{"id":"klsf","name":"快乐十分","term":"201021649","date":"2010-08-11 22:00","numbers":{"normal":"5,11,12,14,20"},"jackpot":"-"},{"id":"klsc","name":"快乐双彩","term":"2010215","date":"2010-08-10 21:25","numbers":{"normal":"12,23,10,15,7,3","special":"11"} ,"jackpot":"198059"}]
i want to gain all of them,but the data is so many,so whether i need to create 8 kinds of class to store the data,so to be easier to use.thanks!
To add to cfei's response, one thing that I've done when processing JSON responses from Flickr, is create a new class particularly for that type of object.
So for yours, just playing it by ear, something like the below:
public class Lottery() {
private JSONObject json;
private String id;
private String name;
private String term;
private String date;
private String norm_numbers;
private String spec_numbers;
private String jackpot;
public Lottery(JSONObject json) {
this.json = json;
}
public void setId()
{
try {
id = json.getString("id");
} catch (JSONException e) {
id = "";
}
}
//additional getters and setters, etc.
}
This way, you can make an array of objects, and access the fields like so:
//...get a JSONObject from the array...
Lottery lottery = new Lottery(json);
Log.v("ID", lottery.id);
Log.v("Name", lottery.name);
and so on.
Do you mean that you want to iterate through each of the eight JSONObjects in this JSONArray? You need to create a JSONArray object with the input string you posed above (let's call it "response", as used below) and then iterate through the array to get each JSONObject it contains. For example:
JSONArray array = new JSONArray(response);
for(int i = 0; i < array.length(); i++) {
JSONObject obj = array.getJSONObject(i);
// do something with obj
// example: to get the id for a particular object, use obj.getString("id")
Log.i("Example", "the id is"+obj.getString("id"));
}