How to pass json object data using Gson?

问题

i know there is lots of solution available but none of them help me i am parsing json data data using Gson, and i want to parse this data to another activity as well but i am getting null pointer exception on that.

 RequestQueue requestQueue = Volley.newRequestQueue(mContext);
    JsonObjectRequest jsOnbjRequest = new JsonObjectRequest(Request.Method.POST,
            Constants.MyProfile,
            userProfile,
            new Response.Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response)
                {
                //    Toast.makeText(mContext, response.toString(), Toast.LENGTH_SHORT).show();
                    progressDialog.dismiss();
                    Gson mGson=new Gson();
                    mMyProfile=mGson.fromJson(response.toString(),MyProfile.class);
                    firstNameView.setText(mMyProfile.getMyProfileDTO().get(0).getFirstName());
                    lashNameView.setText(mMyProfile.getMyProfileDTO().get(0).getLastName());
                    adressNameView.setText(mMyProfile.getMyProfileDTO().get(0).getAddress());
                    countryNameView.setText(mMyProfile.getMyProfileDTO().get(0).getCountry());
                    zipCodeView.setText(mMyProfile.getMyProfileDTO().get(0).getZipCode());
                    emailIdView.setText(mMyProfile.getMyProfileDTO().get(0).getEmail());
                    phonNoview.setText(mMyProfile.getMyProfileDTO().get(0).getPhoneNumber());



                }
            },
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    progressDialog.dismiss();
                    Toast.makeText(mContext, "ErrorMsg" + error.toString(), Toast.LENGTH_SHORT).show();


                }
            });
    requestQueue.add(jsOnbjRequest);
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.edit_profile, menu);
    return super.onCreateOptionsMenu(menu);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case R.id.action_edit:
            if (Connectivity.isConnected(mContext))
            {

                /*Intent userEditProfile = new Intent(mContext, EditProfileActivity.class);
                userEditProfile.putExtra("userProfile",mMyProfile);
                startActivity(userEditProfile);
                overridePendingTransition(R.anim.right_to_left,
                        R.anim.left_to_right);*/
                Intent intent = new Intent(getBaseContext(), EditProfileActivity.class);
                intent.putExtra("profile ", mMyProfile);
                startActivity(intent);

            } else {
                Connectivity.showNoConnection(mContext);
            }

            break;
    }
    return super.onOptionsItemSelected(item);
}

while parsing this data i am not able to get parsing object on that my next Activity is like:

 MyProfile object = getIntent().getExtras().getParcelable("profile");
        userFirstName=object.getMyProfileDTO().get(0).getFirstName();

and log cat point on bean class:

 public class MyProfile implements Parcelable
{

@SerializedName("Status")
@Expose
private String status;
@SerializedName("Message")
@Expose
private String message;
@SerializedName("myProfileDTO")
@Expose
private List<MyProfileDTO> myProfileDTO = null;
public final static Parcelable.Creator<MyProfile> CREATOR = new 
Creator<MyProfile>() {


    @SuppressWarnings({
            "unchecked"
    })
    public MyProfile createFromParcel(Parcel in) {
        return new MyProfile(in);
    }

    public MyProfile[] newArray(int size) {
        return (new MyProfile[size]);
    }

   }
        ;

  protected MyProfile(Parcel in) {
    this.status = ((String) in.readValue((String.class.getClassLoader())));
    this.message = ((String) in.readValue((String.class.getClassLoader())));
    in.readList(this.myProfileDTO, 
 (MyProfileDTO.class.getClassLoader()));//here null pointer exception 
 }

 public MyProfile() {
 }

public String getStatus() {
    return status;
}

public void setStatus(String status) {
    this.status = status;
}

public String getMessage() {
    return message;
}

public void setMessage(String message) {
    this.message = message;
}

public List<MyProfileDTO> getMyProfileDTO() {
    return myProfileDTO;
}

public void setMyProfileDTO(List<MyProfileDTO> myProfileDTO) {
    this.myProfileDTO = myProfileDTO;
}

public void writeToParcel(Parcel dest, int flags) {
    dest.writeValue(status);
    dest.writeValue(message);
    dest.writeList(myProfileDTO);
}

public int describeContents() {
    return 0;
}

}

回答1:

Make your MyProfile.class implement Serializable

make sure your response is in json format and then in onResponse() of volley use GsonBuilder() like this

MyProfile myprofile = new GsonBuilder().create().fromJson(response.toString(), MyProfile .class);

then start activity with intent

    Intent i = new Intent(this, NextActivity.class);
i.putExtra("myprofileObject", myprofile );
startActivity(i);

and receive the object in NextActivity.class like this

Intent intent = getIntent();
MyProfile myprofile = (MyProfile )intent .getSerializableExtra("myprofileObject");

If you implement your class as Parcelable then receive the object in NextActivity.class like this

 Intent intent = getIntent();
    MyProfile myprofile = (MyProfile )intent .getParcelableExtra("myprofileObject");

回答2:

Gson gson = new Gson();
MyProfile obj = new MyProfile();
String jsonInString = gson.toJson(obj);
// pass string object to next activity and convert string object to class.
//next activity write this code.
MyProfile obj= gson.fromJson(jsonInString, MyProfile.class);

回答3:

Instead of passing MyProfile Object as Parcelable, try as below in the sender class:

String data = new Gson().toJson(mMyProfile);

Intent intent = new Intent(getBaseContext(), EditProfileActivity.class);
            intent.putExtra("profile ", data);
            startActivity(intent);

At Receiver class, get your profile info as below:

String data = getIntent().getStringExtra("profile");

MyProfile object = new Gson().fromJson(data,MyProfile.class)

This might work for your case.

来源：https://stackoverflow.com/questions/47530864/how-to-pass-json-object-data-using-gson