Refresh ArrayList to show new data in RecyclerView using Click on Spinner Item

Question

By clicking the SpinnerItem that adds new data to RecyclerView, without deleting the old.

For example, I have twoElements in Spinner : Appliancesand Accessories.

By default, I show Appliancesdata in RecyclerView , but whenever I do tapin Accessories - it shows Accessories datain RecyclerView, but below Appliances data, whereas I was expecting only Accessoriesdata in RecyclerView

MainActivity.java:

public class MainActivity extends AppCompatActivity {

    .....

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_menu_screen);
        .........

        stringList = new ArrayList<String>();
        stringList.add("Appliances");
        stringList.add("Accessories");

        ArrayAdapter<String> stringArrayAdapter = new ArrayAdapter<String>(MainActivity.this,
                android.R.layout.simple_dropdown_item_1line,
                stringList);

        spinnerMenu.setAdapter(stringArrayAdapter);

        ......

        initializeAdapter();

        .....

        spinnerMenu.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {

                switch (position) {
                    case 0:                            

                        presenter.loadAppliances();

                        break;

                    case 1:

                        presenter.loadAccessories();

                        break;
                }

            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {

            }
        });

        .......
    }

    public void initializeAdapter() {

        categoryAdapter = new CategoryAdapter(this, new ArrayList<Category>());
        mRecyclerView.setAdapter(categoryAdapter);
    }

    public void addMenu(List<Category> posts) {
        categoryAdapter.addAllData(posts);
        categoryAdapter.notifyDataSetChanged();
    }

}

CategoryAdapter.java:

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

    public void setPosts(List<Categories> posts) {
        this.posts = posts;
    }

    public void clearData() {
        posts.clear();
    }

    public void addAllData(List<Categories> posts) {
        this.posts.addAll(posts);
    }

}

Answer 1

ArrayList Arraylist.

 public void addMenu(List<Category> posts) {
    categoryAdapter.addAllData(posts);
    categoryAdapter.notifyDataSetChanged();
}

public void addAllData(List<Categories> posts) {
    this.posts.clear();
    this.posts.addAll(posts);
}

Answer 2

reset , . :

 public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
       initializeAdapter();
       //after this the switch case

, Spinner Menu. menupresenter.loadAppliances(); int positionSelected = 0;

switch position
   case: 0
     if(positionSelected != 0) {
         initializeAdapter();
         menupresenter.loadAppliances();
         positionSelected = 0;
     }...

   case: 1
     if(positionSelected != 1) {
         initializeAdapter();
         menupresenter.loadAccessories();
         positionSelected = 1;
     }...      

, reset recyclerView . ,