I am parsing the title correctly and displaying it in a listview. I cant seem to access the
String findMe;
seen below. Here are the two objects, sample response and my call.
response pojo:
public class Response {
public String count;
public Result []results;
}
first object
public class Result {
public String title;
public static arr [] Details;
second object
public class Details {
public Integer _id;
public String findMe;
}
response:
Call<Response> call = api.getListWith(API_KEY);
call.enqueue(new Callback<Response>() {
#Override
public void onResponse(Call<Response> call, Response<Response> response) {
result = response.body();
}
I am getting the title just by passing 'result' into the adapter and using
result[i].getTitle();
I tried using
result[i].Details[0].findMe;
but my error response is:
java.lang.NullPointerException: Attempt to read from null array
public class Result {
public String title;
public Details[] arr;
}
Then
results[i].getarr[0].getfindMe();
Related
I have an example ,I want to understand some parts,In this exampl ,It was working fine ,but when I changed part
from:
call list<model>> method();
to:
call <model> method();
It caused an error ,What's the reason for that?
What is the difference between the two cases?
// MainActivity :
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
GetData service = RetrofitClient.getRetrofitInstance().create(GetData.class);
Call<RetroUsers> call = service.getAllUsers();
call.enqueue(new Callback<RetroUsers>() {
#Override
public void onResponse(Call<RetroUsers> call, Response<RetroUsers> response) {
Log.i("print", "" + response.body().getUser());
}
#Override
public void onFailure(Call<RetroUsers> call, Throwable t) {
Log.i("print", "Dont" + t.getMessage());
}
});
}
///Error message :
I/print: Dontjava.lang.IllegalStateException: Expected BEGIN_OBJECT but was BEGIN_ARRAY at line 1 column 2 path $
// interface GetData:
public interface GetData {
#GET("/users")
Call<RetroUsers>getAllUsers();
/*
#GET("/users")
Call<List<RetroUsers>> getAllUsers();
*/
}
// RetrofitClient :
public class RetrofitClient {
private static Retrofit retrofit;
private static final String BASE_URL = "https://jsonplaceholder.typicode.com";
public static Retrofit getRetrofitInstance() {
if (retrofit == null) {
retrofit = new retrofit2.Retrofit.Builder()
.baseUrl(BASE_URL)
.addConverterFactory(GsonConverterFactory.create())
.build();
}
return retrofit;
}
}
// model class :
public class RetroUsers {
#SerializedName("name")
private String name;
public RetroUsers(String name) {
this.name = name;
}
public String getUser() {
return name;
}
public void setUser(String name) {
this.name = name;
}
}
This: Call<RetroUsers> getAllUsers();
will cause you an error because the getAllUsers() will return more than one records of RetroUsers. Due to which it requires you to provide it a type as List so that its datatype is set to List and it can then handle multiple records.
Go through basics of Core Java to better understand this.
In one case you tell the deserializer that you expect a single Model, in the other case you tell it to expect a list of models, aka a List<Model>. Depending on what data you actually get you need to use one or the oter.
Of course you can "hide" the List<...> within your model by not using List<Model> but:
public class MoreThanOneModel {
public List<Model> entries;
...
}
But that does not change the underlying reasoning.
How can be done retrofit PUT with different types of call and responce bodies?
I have a limitation with error. Types must be identical <T> and <T>.
Responce bodie can contain int value, but call should not, because when i initialize CallBody object with int value, it already contain n1=0, and send this parameter to server.
#PUT("/api/test")
Call<CallBody> test1(#Body CallBody params_body);
public class CallBody {
public String id;
}
public class ResponceBody {
public String s1;
public int n1;
}
public void Test(String id) {
CallBody params_body = new CallBody();
params_body.id = id;
Call<CallBody> call1 = apiInterface.test1(params_body);
call1.enqueue(new Callback<CallBody>() {
#Override
public void onResponse(Call<CallBody> call, Response<ResponceBody> response) {
ResponceBody response = response.body();
}
#Override
public void onFailure(Call<CallBody> call, Throwable t) {
call.cancel();
}
});
}
Try,
public class ResponceBody {
public String s1;
public Integer n1;
}
I am new to android programming and can anyone help me or point out why its giving me this error
I want to fetch some data from the server such as under the Hardware json and get the names and status, but when i call api its shows me this.
Change the line
public void onResponse(Call<List<ObjectList>> call, Response<List<ObjectList>> response) {
to
public void onResponse(Call<List<ObjectList>> call, Response<ObjectList> response) {
As per your code, you are expecting response as List. But Actual response is object. So, you need to generate model class based on your response and set in code for output.
Your Model should be like :
public class Application {
ArrayList<Object> hardware = new ArrayList<Object>();
Header HeaderObject;
ArrayList<Object> software = new ArrayList<Object>();
// Getter Methods
public Header getHeader() {
return HeaderObject;
}
// Setter Methods
public void setHeader( Header headerObject ) {
this.HeaderObject = headerObject;
}
}
public class Header {
Stamp StampObject;
private String frame_id;
private float seq;
// Getter Methods
public Stamp getStamp() {
return StampObject;
}
public String getFrame_id() {
return frame_id;
}
public float getSeq() {
return seq;
}
// Setter Methods
public void setStamp( Stamp stampObject ) {
this.StampObject = stampObject;
}
public void setFrame_id( String frame_id ) {
this.frame_id = frame_id;
}
public void setSeq( float seq ) {
this.seq = seq;
}
}
public class Stamp {
private float secs;
private float nsecs;
// Getter Methods
public float getSecs() {
return secs;
}
public float getNsecs() {
return nsecs;
}
// Setter Methods
public void setSecs( float secs ) {
this.secs = secs;
}
public void setNsecs( float nsecs ) {
this.nsecs = nsecs;
}
}
Then change below line :
public void onResponse(Call<List<ObjectList>> call, Response<Application> response) {
Change this:
#GET("system_monitor")
Call<List<ObjectList>> getHardware();
to
#GET("system_monitor")
Call<ObjectList> getHardware();
Your response return an object instead of array.
Instead of
#GET("system_monitor")
Call<List<ObjectList>> getHardware();
use
#GET("system_monitor")
Call<ObjectList> getHardware();
And then use it like below:
Call<ObjectList> call = webRequestAPI.getHardware();
call.enqueue(new Callback<ObjectList>() {
#Override
public void onResponse(Call<ObjectList> call, Response<ObjectList> response) {
if (!response.isSuccessful()) {
textViewHardwareName.setText("Code: " + response.code());
return;
}
ObjectList system_monitor = response.body();
...
}
#Override
public void onFailure(Call<ObjectList> call, Throwable t) {
textViewHardwareName.setText(t.getMessage());
}
});
The best thing for your scenario hardware and Software are as objects , which have two property
1.Name 2. Object status.
So I recommend you to create a class name as System and put there these two variables so finally your class looks like :
Class System
{
String object_name;
boolean object_status;
}
and your getter setter .
And update your model class like this
#SerializedName("hardware")
#Expose
public List<System> hardware;
#SerializedName("software")
#Expose
public List<System> software;
and change your retrofit response holder as.
public void onResponse(Call<List<ObjectList>> call, Response<ObjectList>
response) {
I'm using Retrofit to make API call, When I handle the response I get the next error (Need to get the data from the API call) -
Attempt to invoke interface method 'java.lang.Object java.util.List.get(int)' on a null object reference
I don't know if I'm doing it right. Anyway here's my code.
Here's the url link: https://data.gov.il/api/
Retrofit call -
#GET("datastore_search?resource_id=2c33523f-87aa-44ec-a736-edbb0a82975e")
Call<Result> getRecords();
Retrofit base call -
private static Retrofit retrofit;
public static final String BASE_URL = "https://data.gov.il/api/action/";
public static Retrofit getRetrofitInstance() {
if (retrofit == null) {
retrofit = new retrofit2.Retrofit.Builder()
.baseUrl(BASE_URL)
.addConverterFactory(GsonConverterFactory.create())
.build();
}
return retrofit;
}
Model class -
public class Result {
#SerializedName("include_total")
#Expose
private Boolean includeTotal;
#SerializedName("resource_id")
#Expose
private String resourceId;
#SerializedName("fields")
#Expose
private List<Field> fields = null;
#SerializedName("records_format")
#Expose
private String recordsFormat;
#SerializedName("records")
#Expose
private List<Record> records = null;
#SerializedName("limit")
#Expose
private Integer limit;
#SerializedName("_links")
#Expose
private Links links;
#SerializedName("total")
#Expose
private Integer total;
public Boolean getIncludeTotal() {
return includeTotal;
}
public void setIncludeTotal(Boolean includeTotal) {
this.includeTotal = includeTotal;
}
public String getResourceId() {
return resourceId;
}
public void setResourceId(String resourceId) {
this.resourceId = resourceId;
}
public List<Field> getFields() {
return fields;
}
public void setFields(List<Field> fields) {
this.fields = fields;
}
public String getRecordsFormat() {
return recordsFormat;
}
public void setRecordsFormat(String recordsFormat) {
this.recordsFormat = recordsFormat;
}
public List<Record> getRecords() {
return records;
}
public void setRecords(List<Record> records) {
this.records = records;
}
...
Main Activity -
RecallService service = RetrofitClientInstance.getRetrofitInstance().create(RecallService.class);
Call<Result> records = service.getRecords();
records.enqueue(new Callback<Result>() {
#Override
public void onResponse(Call<Result> call, Response<Result> response) {
Log.d(TAG, String.valueOf(response.body().getRecords().get(0).getId())); // ERROR
}
#Override
public void onFailure(Call<Result> call, Throwable t) {
Log.e(TAG, t.getMessage());
}
});
The response, which you are getting from the API, doesn't fit the Result POJO.
The response you get from API is like below:
{
"help": "https://data.gov.il/api/3/action/help_show?name=datastore_search",
"success": true,
"result": {...}
}
By using the Result POJO, you are assuming that you get the response as below, which is a json inside the actual response json, and is not what you actually receive. So, just create a POJO which fairly represents the actual response.
{
"include_total": true,
"resource_id": "2c33523f-87aa-44ec-a736-edbb0a82975e",
"fields": [...],
"records_format": "objects",
"records":[...]
}
Try making a class like below (set the annotations yourself):
class Resp{
Result result;
}
Replace the class Result with Resp, like below and other usages:
#GET("datastore_search?resource_id=2c33523f-87aa-44ec-a736-edbb0a82975e")
Call<Resp> getRecords();
Then, finally you can do:
response.body().getResult().getRecords()
The API link you've shared returns the response in the format below:
{"help": "https://data.gov.il/api/3/action/help_show?name=datastore_search", "success": true, "result": {...}}
You are setting the response object to be of type Result which is actually a sub-element within the root element help in the json response. response.body() would include help and the result would be it's sub-element. Since it is not parsed correctly, you're getting a null response.
You will need to include the root element in your model class and update the API call to use that class type as the response type.
I am using retrofit 2.0 Gson data not getting
When i check Postman i am getting response below
{
"name": "Yashodhan Communication",
"zone": "9-Belgaum",
"tsm_name": "Tarun Patil",
"asm_name": "Shivakumar Patil"
}
Error:
java.lang.IllegalStateException: Expected BEGIN_ARRAY but was
BEGIN_OBJECT at line 1 column 2 path $
APIClient Client
public static Retrofit getClient() {
retrofit = new Retrofit.Builder()
.baseUrl("http://vehiclerescue.in/ideadarpan_beta/")
.addCallAdapterFactory(RxJava2CallAdapterFactory.create())
.addConverterFactory(GsonConverterFactory.create())
.build();
return retrofit;
}
This is Pojo class
public class Appuser_Pojoclass {
#SerializedName("name")
#Expose
private String name;
#SerializedName("zone")
#Expose
private String zone;
#SerializedName("tsm_name")
#Expose
private String tsm_name;
#SerializedName("asm_name")
#Expose
private String asm_name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getZone() {
return zone;
}
public void setZone(String zone) {
this.zone = zone;
}
public String getTsm_name() {
return tsm_name;
}
public void setTsm_name(String tsm_name) {
this.tsm_name = tsm_name;
}
public String getAsm_name() {
return asm_name;
}
public void setAsm_name(String asm_name) {
this.asm_name = asm_name;
}
}
Activity class
private void fetchAllAppUserdata()
{
progressBar.setVisibility(View.VISIBLE);
Log.d("getauthkeydisplay","**** "+Idea_Urban.getInstance().get_Authkeyvalues());
ideaInterface.get_AppUsers(Idea_Urban.getInstance().get_Authkeyvalues()).enqueue(new Callback<List<Appuser_Pojoclass>>() {
#Override
public void onResponse(Call<List<Appuser_Pojoclass>> call, Response<List<Appuser_Pojoclass>> response) {
if(app_users != null)
{
progressBar.setVisibility(View.INVISIBLE);
app_users.clear();
}
if(response.body()!=null) {
app_users.addAll(response.body());
Log.d("appuserresponce","***** "+response.body());
// app_userDetailsAdapter.notifyDataSetChanged();
}else
{
progressBar.setVisibility(View.INVISIBLE);
}
}
#Override
public void onFailure(Call<List<Appuser_Pojoclass>> call, Throwable t) {
Log.d("failure","**** ");
Log.d("printmetthodsfailure","faiure"+call.toString() + "\n " + t.toString());
progressBar.setVisibility(View.INVISIBLE);
}
});
}
I found some solution as google suggestion but i donot know how to achieve.
You problem is java.lang.IllegalStateException: Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 2 path $
So you should check you response of your code .
Your JSON response is JSONObject ,so you should use Call<Appuser_Pojoclass> call
Change
Call<List<Appuser_Pojoclass>> call
to
Call<Appuser_Pojoclass> call
The error is in the Call declaration,change
Call<List<Appuser_Pojoclass>>
with
Call<Appuser_Pojoclass>
Your retrofit call response type is <List<Appuser_Pojoclass>> but your API response is not a list of Appuser_Pojoclass, it is simply a single object of type Appuser_Pojoclass.
Change type from <List<Appuser_Pojoclass>> to Appuser_Pojoclass in your retrofit call
You probably defined your get_AppUsers method as something that returns Call<List<Appuser_Pojoclass>> instead of just Call<Appuser_Pojoclass> so it ends up looking for a JSON array, but then your response only contains a single JSON object which causes the error. Change get_AppUsers to return Call<Appuser_Pojoclass> and then change your callback accordingly and that should fix the problem.