How to pass data from a user activity to a recyclerview?

Question

I want to make a interface which user can add its data to activity and after its must be show on in recyclerview, I used manual data adding in code it's working but I want to user must be able to store its data on application and can see & modified.

I used put_extra function but is not working.`

[code for put_put Extra]

Here is adapter class:

public class Handler_Adapter extends RecyclerView.Adapter<Handler_Adapter.MyViewHolders> {
    ArrayList<MyMode> myModel;
    View ReceivedImages;
    Context context;
    public Handler_Adapter (Context context, ArrayList<MyMode> list, View myImagesF){
       this.context=context;
        this.myModel=list;
        ReceivedImages=myImagesF;
    }

    @Override
    public MyViewHolders onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        LayoutInflater inflater= LayoutInflater.from(context);
        View view = inflater.inflate(R.layout.row,parent,false);
        return null;
    }
@Override
public void onBindViewHolder(@NonNull MyViewHolders holder, int position) {
    holder.EName.setText(myModel.get(position).getLangName());
    holder.E_Des.setText(myModel.get(position).getLangName());
    holder.Price.setText(myModel.get(position).getLangName());
    holder.itemsSize.setText(myModel.get(position).getLangName());
    holder.myImages.setImageResource(myModel.get(position).getLangLogo());
    holder.rows.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

        }
    });
}

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

public class MyViewHolders extends RecyclerView.ViewHolder {
    TextView EName,E_Des,Price,itemsSize;
    ImageView myImages;
    RelativeLayout rows;
    public MyViewHolders(@NonNull View itemView) {
        super(itemView);
        EName=itemView.findViewById(R.id.EName);
        E_Des=itemView.findViewById(R.id.E_Des);
    ReceivedImages=itemView.findViewById(R.id.my_Imaage);
        Price=itemView.findViewById(R.id.E_Price);
        itemsSize=itemView.findViewById(R.id.itemsSize);
       rows=itemView.findViewById(R.id.rows);
    }
}

}

Here is UserActivity

public class AddMenu extends AppCompatActivity {
public static final String TEXT_TO_SEND="com.example.EMenu.TEXT_TO_SEND";
private ImageView mImageView;
private EditText EName,E_Des,E_Price,E_size;
private Button Import;
private String TextToSend;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_add_menu);



        mImageView=findViewById(R.id.imageFilterView);
        mImageView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                ImagePicker.Companion.with(AddMenu.this)
                .crop()
               // .cropOval()
                        .compress(1024)
                        .maxResultSize(1080,1080)
                        .start();
            }
        });
    Import=findViewById(R.id.Import);
    EName=findViewById(R.id.EName);
    E_Des=findViewById(R.id.E_Des);
    E_Price=findViewById(R.id.E_Price);
    E_size=findViewById(R.id.E_size);
    Import.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
             TextToSend=EName.toString().toUpperCase().trim();
             TextToSend=E_Des.toString().toLowerCase().trim();
             TextToSend=E_Price.toString().toUpperCase().trim();
             TextToSend=E_size.toString().toUpperCase().trim();
            gotoActivity();
        }
    });
}

private void gotoActivity() {
    Intent on=new Intent(AddMenu.this,Mainpage.class);
     on.putExtra("Selected_Image",R.id.imageFilterView);
       on.putExtra(TEXT_TO_SEND, String.valueOf(EName).toUpperCase());
       on.putExtra(TEXT_TO_SEND, String.valueOf(E_Des));
       on.putExtra(TEXT_TO_SEND, String.valueOf (E_Price).toUpperCase());
       on.putExtra(TEXT_TO_SEND, String.valueOf(E_size).toUpperCase());
    startActivity(on);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    Uri uri=data.getData();
    mImageView.setImageURI(uri);
}

**Main page code_ at there is

used adding images manually but I want to its added it by user activity**

public class Mainpage extends AppCompatActivity {
    RecyclerView Recycler;
    ArrayList<MainModels> mainModel;
    MainAdapter mainAdapter;
    Handler_Adapter mHandler_adapter;
    ArrayList<MyMode> myModel;
    SearchView SearchView;
    ImageView mImageView,myImagesF;

    ////////////////////////////////////////////////////////: Images resource file..
    String s1[],s2[],s3[],s4[];

    /////////////////////////////////////////////////////.......... continue..............
    RecyclerView recyclerView;
    NavigationView click;
    private FirebaseAuth fAuth;
    private String currentUserId;
    private DatabaseReference databaseReference;
    Button Navigation;
    //Menu Account,Settings,Restaurant,Menu;
    private DrawerLayout mDrawerLayout;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_mainpage);
        myModel = new ArrayList<>();
        int images[]={R.drawable.delfina_cocciardi_ndpbk_d_03m_unsplash,R.drawable.ic_launcher_foreground,
                R.drawable.ic_launcher_foreground,R.drawable.ic_launcher_foreground,R.drawable.ic_launcher_foreground    };
         /////////////////////////////////////.......Goat it data from input data fragment
    mImageView=findViewById(R.id.my_Imaage);
    Bundle bundle=getIntent().getExtras();
    if (bundle != null){
        int res_image=bundle.getInt("Selected_Image");

// mImageView.setImageResource(res_image);

    }
    //////////////////////////////////////////////////................!!!

    recyclerView=findViewById(R.id.recyclerView);
    Intent intent=getIntent();
    s1=getResources().getStringArray(R.array.Menu_items);
    s2=getResources().getStringArray(R.array.Description);
    s3=getResources().getStringArray(R.array.Prices);
    s4=getResources().getStringArray(R.array.Prices);
    Adapter mAdapter=new Adapter(this,s1,s2,s3,s4,images);
    recyclerView.setAdapter(mAdapter);
    recyclerView.setLayoutManager(new GridLayoutManager(this,2,RecyclerView.VERTICAL,false));


    /*
    recyclerView=findViewById(R.id.recyclerView);
    Integer[] langLogos={R.id.imageFilterView};

    Intent intent=getIntent();
    String langNames=intent.getStringExtra(AddMenu.TEXT_TO_SEND);
    if (langNames!=null){
        TextView textView=findViewById(R.id.Menu_Name);
        textView.setText(langNames);
    }

    String langPrice=intent.getStringExtra(AddMenu.TEXT_TO_SEND);
    if (langPrice!=null){
        TextView textView2=findViewById(R.id.Description_name);
        textView2.setText(langPrice);
    }
    String langDisc=intent.getStringExtra(AddMenu.TEXT_TO_SEND);
    if (langDisc!=null){
        TextView textView3=findViewById(R.id.Price);
        textView3.setText(langDisc);
    }
    String langSize=intent.getStringExtra(AddMenu.TEXT_TO_SEND);
    if (langSize!=null){
        TextView textView4=findViewById(R.id.itemsSize);
        textView4.setText(langSize);
    }

    myModel=new ArrayList<>();
    MyMode so=new MyMode(langLogos,langNames,langDisc,langPrice,langSize);
    myModel.add(so);
    GridLayoutManager gridLayoutManager= new GridLayoutManager(Mainpage.this,2,GridLayoutManager.VERTICAL,false);
    recyclerView.setLayoutManager(gridLayoutManager);
    recyclerView.setItemAnimator(new DefaultItemAnimator());
    mHandler_adapter=new Handler_Adapter(Mainpage.this,myModel,myImagesF);
    recyclerView.setAdapter(mHandler_adapter);


     */
   // for (int j=0;j<langLogos.length;j++){
  //  }

Answer 1

Here is what you can do. Create a private list in your activity.

    @Override
    protected void onCreate(Bundle savedInstanceState)  {
        super.onCreate(savedInstanceState);
        myModel = new ArrayList<>();
    }

Now change the constructor of your adapter.

 public Handler_Adapter(Context context, ArrayList<MyModels> list, ...) 
 {
  ...
  this.myModelList = list;
  ...
  }

Now when you modify "myModel" than this is visible to your adapter. All you have to do is to call the following once you modify it.

mHandlerAdapter.notifyDataSetChanged();