unable to pass in the position Recyclerview using the interface

Question

I am a beginner who just has started to learn Android. I am currently stuck with a problem that I am unable to solve

I have to made an interface that is going to send a recyclerview position(int) from the Adapter to the mainActivity

Here is my interface

public interface OnButtonClicked {

public void On_Button_Cancel_Clicked(int position);

}

Here is my Adapter

public class AppointmentAdapter extends RecyclerView.Adapter<AppointmentAdapter.SenderViewHolder> {

ArrayList<Users> list;
Context context;
OnButtonClicked onButtonClicked;

public AppointmentAdapter(ArrayList<Users> list, Context context, OnButtonClicked onButtonClicked) {
    this.list = list;
    this.context = context;
    this.onButtonClicked = onButtonClicked;
}

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

@Override
public void onBindViewHolder(@NonNull SenderViewHolder holder, int position) {
    Users users = list.get(position);
    holder.username.setText(users.getUsername());
    holder.token_no.setText("!2:00");
    holder.time.setText("12:00");
    Picasso.get().load(users.getProfile_pic()).placeholder(R.drawable.ic_impatient).into(holder.image);


    holder.call.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
             Intent intent = new Intent(Intent.ACTION_DIAL);
            intent.setData(Uri.parse("tel:"+ users.getMobile()));
            v.getContext().startActivity(intent);
        }
    });

    holder.Camera.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
             //here is the interface position i am trying to pass
            String s = users.getId();
            Appointment obj = new Appointment();
            obj.On_Button_Cancel_Clicked(holder.getLayoutPosition());//<--this is my //problem i am trying to send adapter position to main activity and when i run the code the //and try to print the layout position i am getting the output in the android terminal but //my app crashes
        }
    });

}

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


public static class SenderViewHolder extends RecyclerView.ViewHolder{
    CircleImageView image;
    TextView username, token_no, time;
    Button call, cancel, Camera;
    LinearLayout linear_layout;
    OnButtonClicked onButtonClicked;

    public SenderViewHolder(@NonNull View itemView) {
        super(itemView);
        image = (CircleImageView) itemView.findViewById(R.id.app_user_image);
        username = (TextView) itemView.findViewById(R.id.app_Username);
        token_no = (TextView) itemView.findViewById(R.id.app_token);
        time = (TextView) itemView.findViewById(R.id.app_time);
        call = (Button) itemView.findViewById(R.id.app_call);
        cancel = (Button) itemView.findViewById(R.id.app_close);
        Camera = (Button) itemView.findViewById(R.id.app_Take_picture);
    }
}

}

Here is my main Activity Appointment.java

I've initialized the constructor

I implemented the interface in my main activity

public class Appointment extends AppCompatActivity implements OnButtonClicked {

AppointmentAdapter appointmentAdapter = new AppointmentAdapter(messageModels, getApplicationContext(), this::On_Button_Cancel_Clicked);

public void On_Button_Cancel_Clicked(int position) {
    System.out.println(position);
}

//when I try to print the position in my main activity using "System.out.println()" the program runs fine and the app wont crash 1.)Outputs when i use Sout I/System.out: 0 ->on clicking position 0 I/System.out: 1 ->on clicking position 1

but when I try to make a Toast in the interface here my app crashes

public void On_Button_Cancel_Clicked(int position) {
    Toast.makeText(activity, position, Toast.LENGTH_SHORT).show();
}

}

the error is

E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.nowait, PID: 12735 java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()' on a null object reference at android.widget.Toast.makeText(Toast.java:315) at com.example.nowait.Appointment.On_Button_Cancel_Clicked(Appointment.java:242)<-- at com.example.nowait.AppointmentAdapter$2.onClick(AppointmentAdapter.java:76)<-- at android.view.View.performClick(View.java:7185) at android.view.View.performClickInternal(View.java:7162) at android.view.View.access$3500(View.java:819) at android.view.View$PerformClick.run(View.java:27684) at android.os.Handler.handleCallback(Handler.java:883) at android.os.Handler.dispatchMessage(Handler.java:100) at android.os.Looper.loop(Looper.java:224) at android.app.ActivityThread.main(ActivityThread.java:7590) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:539) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:950)

AppointmnetAdapter.java:76 obj.On_Button_Cancel_Clicked(holder.getLayoutPosition());

Appointment.java:242 Toast.makeText(Appointment.this, position, Toast.LENGTH_SHORT).show();

please help me i am struck with this for 4 days

Rather than calling method on obj variable in setOnClickListener method, you should call the method on your onButtonClicked variable of adapter like this - - > this.onButtonClicked.On_Button_Cancel_Clicked(holder.getLayoutPosition()); — Nikhil Jain, Jul 24 '21 at 18:37
And in MainActivity, while creating the AppointmentAdapter, pass an anonymous class object as an argument where you can put the code like Toast you're trying to execute. — Nikhil Jain, Jul 24 '21 at 18:40

unable to pass in the position Recyclerview using the interface

0 Answers0