App crash on resp.getMessage() call

Question

i want to get server response during register process, but unfortunately my app keeps crashing here

 response.enqueue(new Callback<ServerResponse>() {
        @Override
        public void onResponse(Call<ServerResponse> call, retrofit2.Response<ServerResponse> response) {

            ServerResponse resp = response.body();
//crash occurs here
            Toast.makeText(getApplicationContext(), resp.getMessage(), Toast.LENGTH_LONG).show();

and this is what logcat says

java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.chat.ServerResponse.getMessage()' on a null object reference
                                                              at com.chat.RegisterActivity$3.onResponse(RegisterActivity.java:130)
                                                              at retrofit2.ExecutorCallAdapterFactory$ExecutorCallbackCall$1$1.run(ExecutorCallAdapterFactory.java:68)
                                                              at android.os.Handler.handleCallback(Handler.java:739)
                                                              at android.os.Handler.dispatchMessage(Handler.java:95)
                                                              at android.os.Looper.loop(Looper.java:158)

below is my serverResponse class

public class ServerResponse {

private String result;
private String message;
private User user;

public String getResult() {
    return result;
}

public String getMessage() {
    return message;
}

public User getUser() {
    return user;
}
}

Possible duplicate of [What is a NullPointerException, and how do I fix it?](https://stackoverflow.com/questions/218384/what-is-a-nullpointerexception-and-how-do-i-fix-it) — AskNilesh, Nov 01 '17 at 04:22

score 1 · Answer 1 · answered Nov 01 '17 at 04:30

1

Update your method like this:

response.enqueue(new Callback<ServerResponse>() {
        @Override
        public void onResponse(Call<ServerResponse> call, retrofit2.Response<ServerResponse> response) {

            ServerResponse resp = response.body();

            //check your resp is null or resp.getMessage() is nul here
            if(resp!=null && resp.getMessage() != null)
                Toast.makeText(getApplicationContext(), resp.getMessage(), Toast.LENGTH_LONG).show();

it'll solve your problem.

answered Nov 01 '17 at 04:30

HassanUsman

1,787
1
20
38

If I do that then no response is gotten at all and nothing happens – Mani Nov 01 '17 at 04:42
it because your response is `null` check your response or share your response here – HassanUsman Nov 01 '17 at 04:49
I just added my `serverResponse.class` – Mani Nov 01 '17 at 05:15
*Debug* and see what is `response` in your `onResponse` method. – HassanUsman Nov 01 '17 at 05:22
I think your response is null so fix it from server side. – HassanUsman Nov 01 '17 at 05:23
would you like to see the php files? – Mani Nov 01 '17 at 08:02
Just share what you get in your `response` – HassanUsman Nov 01 '17 at 09:02
in my php files? – Mani Nov 01 '17 at 09:30
yeah, what you're receiving n your `onResponse` method? – HassanUsman Nov 01 '17 at 09:37
I tested it with postman and it worked fine. I think the problem is coming from `resp.getMessage()` logcat points to it – Mani Nov 02 '17 at 00:56

score 0 · Answer 2 · answered Nov 01 '17 at 04:30

0

The crash might be due to the implementation of Toast, create a separate function for toast then declare it, and it seems that toast is falling in the loop. It results in the crash of app.

answered Nov 01 '17 at 04:30

how can I do that? – Mani Nov 04 '17 at 04:06

score 0 · Answer 3 · answered Nov 01 '17 at 04:49

0

Make sure that you have created the pojo class like this format..

 public class ServerResponse {

@SerializedName("MESSAGE")
private String MESSAGE;

@SerializedName("MESSAGE")
public void setMESSAGE(String MESSAGE) {
    this.MESSAGE= MESSAGE;
}
@SerializedName("MESSAGE")
public String getMessage() {
    return MESSAGE;
}
}

answered Nov 01 '17 at 04:49

gStephin

332
3
20

please print the response in this format . Log.w("reseP", new Gson().toJson(response)); – gStephin Nov 02 '17 at 05:18

App crash on resp.getMessage() call

3 Answers3