将 ArrayList 从 RecyclerView 传递到另一个 Activity

Question

I am trying to pass the data, which is set in the mainactivity.java into another activity(infoPage.java) but i cant seem to get it working.

MainActivity.java

data = new ArrayList<>();
       data.add( new CarData("Toyota Camry 2010 2.4V","Automatic","5 Seater","Petrol/Full","RM 40 /h",R.drawable.camry2010));


       recyclerView= findViewById(R.id.browsedRecycler);
       recyclerView.setLayoutManager(new LinearLayoutManager(this));
       adapter = new Adapter(this,data);
       recyclerView.setAdapter(adapter);

constructor for model class

public CarData(String title , String trans, String seats, String fuel, String price, int imgID) {

        this.title = title;
        this.trans = trans;
        this.seats = seats;
        this.fuel = fuel;
        this.price = price;
        this.imgID = imgID;
    }

Adapter class

public class Adapter extends RecyclerView.Adapter<Adapter.ViewHolder> {


    private LayoutInflater layoutInflater;
    private List<CarData> data;

    public Adapter(Context context, List<CarData>data) {
        this.layoutInflater = LayoutInflater.from(context);
        this.data = data;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
        View view = layoutInflater.inflate(R.layout.itemlist,viewGroup,false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {

        //to bind the textview with data received

       String title = data.get(position).getTitle();
       String trans = data.get(position).getTrans();
       String seat = data.get(position).getSeats();
       String fuel = data.get(position).getFuel();
       String price = data.get(position).getPrice();
       int imgid = data.get(position).getImgID();
        holder.texttitle.setText(title);
        holder.trans.setText(trans);
        holder.seats.setText(seat);
        holder.fuel.setText(fuel);
        holder.price.setText(price);
        holder.imageView.setImageResource(imgid);

    }

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

    public class ViewHolder extends RecyclerView.ViewHolder{

        TextView texttitle,trans,seats,fuel,price;
        ImageView imageView;
       public ViewHolder(@NonNull View itemView) {
           super(itemView);

           itemView.setOnClickListener(new View.OnClickListener() {
               @Override
               public void onClick(View view) {

                   Intent i = new Intent(view.getContext(),infoPage.class);
                   i.putExtra("title", (data.get(getAbsoluteAdapterPosition())));
                   view.getContext().startActivity(i);
               }
           });

           texttitle = itemView.findViewById(R.id.textTitle);
           trans = itemView.findViewById(R.id.carTrans);
           seats = itemView.findViewById(R.id.seats);
           fuel = itemView.findViewById(R.id.fuel);
           price = itemView.findViewById(R.id.price);
           imageView=itemView.findViewById(R.id.itemImage);
       }
   }

my infopage.java has nothing much yet basically, just the declaration of the textviews and imageviews infoPage.java

 TextView textView;
    ImageView carimage;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_cars_info_page);

        textView=findViewById(R.id.detailText);
        carimage=findViewById(R.id.carsimg);

I've figured it out myself thanks for all the help!

Answer 1

for passing an ArrayList to another activity you should make your model class Parcelable, for doing this you can use the Parcelable plugin that adds some required codes to your model class and make it Parcelable. you can use different plugins for this work, but the plugin that I use for my projects is "Android ParceLable Code Generator" by Michal Charmas. You can download this plugin from the below path: File-> Settings-> Plugins After this , you should use putParcelableArrayListExtra() method to pass arraylist to destenation activity. You can get the Arraylist in destination Activity using getIntent().getParcelableArrayExtra() method that needs one parameter and that parameter is the String key that you specify in the first Activity

Answer 2

I just realized that you are sending the data in wrong way. The right way is to use getters and setters. If you don't know about them then you can have a look at this - https://www.c-sharpcorner.com/article/recyclerview-in-andriod-with-java/

So, you need to do changes in the class where you have created constructors(Let's say Data Class) and use getters and setters there.

Initialize Data class in Mainactivity and set your data with the help of setters and then initialize the Data class in Adapter and get your data with the help of getters.