java - Volley library error in android studio using json object

Question

i created a delete address class

code

public class DeleteAddress {
    boolean result = false;
    String addressid;

    public boolean delAddress(Context context, final int id){

        addressid = Integer.toString(id);

        StringRequest stringRequest = new StringRequest(
                Request.Method.POST,
                Constants.URL_DELETE_ADDRESS,
                new com.android.volley.Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {

                        try {

                            JSONObject jsonObject = new JSONObject(response);
                            if(jsonObject.getBoolean("error")){
                                result = false;
                            }
                            else {
                                result = true;
                            }


                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }

                },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        System.out.println(error.getMessage());
                        result = false;
                    }
                }

        ){
            @Override
            protected Map<String, String> getParams() throws AuthFailureError {
                Map<String, String> params = new HashMap<>();
                params.put("id", addressid);
                return params;
            }

        };

        RequestHandler.getInstance(context).addToRequestQueue(stringRequest);

        return result;
    }
}

the code for address adapter

public class AddressAdapter extends RecyclerView.Adapter<AddressHolder>{
    private ArrayList<Address> dataList;
    Context context;
    int id;
    
    DeleteAddress deleteAddress = new DeleteAddress();

    public AddressAdapter(Context context, ArrayList<Address> list){
        this.context = context;
        this.dataList= list;
    }

    @NonNull
    @Override
    public AddressHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        LayoutInflater inflater = LayoutInflater.from(parent.getContext());
        View view = inflater.inflate(R.layout.row, parent, false);
        return new AddressHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull AddressHolder holder, int position) {
        holder.bind(dataList.get(position));
        id = holder.getAddressId(dataList.get(position));


        holder.deleteAddress.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(context);
                alertDialogBuilder.setMessage("Are you sure you want to delete this address?");
                alertDialogBuilder.setPositiveButton("Yes",
                        new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface arg0, int arg1) {
                                //dummy
                                arg0.cancel();
                                //System.out.println(id);                   working fine
                                if(deleteAddress.delAddress(context, id)){
                                    Toast.makeText(context, "Address record deleted!", Toast.LENGTH_SHORT).show();
                                }
                                else {
                                    Toast.makeText(context, "Some error occurred!", Toast.LENGTH_SHORT).show();
                                }

                                Intent i = new Intent(context, AddressListActivity.class);
                                i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                                context.startActivity(i);
                            }
                        });

                alertDialogBuilder.setNegativeButton("No", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface arg0, int i) {
                        arg0.cancel();
                    }
                });

                AlertDialog alertDialog = alertDialogBuilder.create();
                alertDialog.show();
            }
        });
    }

    @Override
    public int getItemCount() {
        return dataList.size();
    }
}

so let me explain what i am trying to do.
I have made a layout that displays address in Address activity and i am displaying data from mysql php backend. this activity is working fine. i added two items in the recycler view using which we can edit and delete a particular address record. edit button is working fine but delete isn't working.
If i click on delete button i get toast message some error occured. but if i test the button 2-3 times i get the same message but the record gets deleted. web services are working fine so no issues with that.
there are no errors in logcat.

I don't know what is going on. can someone help. need any more portion of code i can update it...

EDIT: i have caught the error. in the deleteaddress class for some reason the value of result variable is not getting updated inside the String request method. i tried to print the message from the web service in the logcat and it shows that address is getting deleted and i checked the database is also getting updated but still i get the toast message that some error occured.

Answer 1

onResponse(String response) is asynchron method

you updates result in callback function. The method delAddress returns always false. (it returns true in second execution, because result was later updated)

your code should be changed like:

make new interface

public interface CallbackClass {
    void onSuccess();
    void onFail(String message);
}

change

public boolean delAddress(Context context, final int id)

to

public void delAddress(Context context, final int id, CallbackClass callback)

then

result = false;

could be like

callback.fail("error");

and

result = true;

could be like

callback.success();

and at least

if(deleteAddress.delAddress(context, id)){
    Toast.makeText(context, "Address record deleted!", Toast.LENGTH_SHORT).show();
} else {
    Toast.makeText(context, "Some error occurred!", Toast.LENGTH_SHORT).show();
}

to

deleteAddress.delAddress(context, id, new CallbackClass(){
    void onSuccess(){
        Toast.makeText(context, "Address record deleted!", Toast.LENGTH_SHORT).show();
    }
    void onFail(String message){
        Toast.makeText(context, "Some error occurred!", Toast.LENGTH_SHORT).show();
    }
});