I have an activity called ListOfPetsActivity.java which is displaying a ListView of Pet object. Pet.java looks like this

    public class Pet {
    
        private int petId;
        private String petName;
        private int age;
        //getters, setters and constructors
    }

I am displaying the pet objects in the ListView with a custom adapter which currently only displays the pet's name and has a button called requestAcceptButton.

Here is the adapter

    public class RequesterAdapter extends ArrayAdapter<Pet> {
    
        private List<Pet> requestersList;
        private Context context;
    
        public RequesterAdapter(Context context, List<Pet> requestersList) {
            super(context, -1, requestersList);
            this.context = context;
            this.requestersList = requestersList;
        }
    
        @NonNull
        @Override
        public View getView(int position, @Nullable View currentItemView, @NonNull ViewGroup parent) {
            if (currentItemView == null) {
                currentItemView = LayoutInflater.from(getContext()).inflate(R.layout.requester_item, parent, false);
            }
    
            // get the position of the view from the ArrayAdapter
            Pet currentPetPosition = getItem(position);
    
            TextView requesterNameTextView = currentItemView.findViewById(R.id.requesterNameTextView);
            requesterNameTextView.setText(currentPetPosition.getPetName()   ", "  currentPetPosition.getAge());
    
            Button requestAcceptButton = currentItemView.findViewById(R.id.requestAcceptButton);
            
            return currentItemView;
        }
    
    }

Now, the current activity which shows the ListView of all the pets, ListOfPetsActivity.java shows the list of pets with their name and age and has a button next to it.
When I click on it, I want to get all values from the pet object from that ListView item and save it in variables of string and int type so that I can communicate with the database. The thing is, I need to do that in this activity and not in the adapter. So, how am I able to get all items from the ListView item?

I am setting up the ListView and its adapter like this in the ListOfPetsActivity.

    RequesterAdapter requesterAdapter = new RequesterAdapter(ListOfPetsActivity.this, friendRequesterPetsList);
    requesterListView.setAdapter(requesterAdapter);

CodePudding user response：

Step1: Create one interface

interface PetClickListener {
      fun onPetSelected(petAge: Int)
}

Step2: Implement interface in your Activity:

ListOfPetsActivity implement PetClickListener {
{
  override onPetSelected(petAge: Int) {
       // here you will get pet Age of selected Pet in the list
  }
}

Step3: update your adapter constructor:

RequesterAdapter requesterAdapter = new RequesterAdapter(ListOfPetsActivity.this, friendRequesterPetsList, this);

Step4: Create one global variable in adapter:

private PetClickListener petClickListener;

Step5: Initialise it in constructor:

public RequesterAdapter(Context context, List<Pet> requestersList, PetClickListener listener) {
        super(context, -1, requestersList);
        this.context = context;
        this.requestersList = requestersList;
        petClickListener = listener;
    }

Step6: use this petClickListener when you click on button

requestAcceptButton.setOnClickListener {
    petClickListener(currentPetPosition.getAge())
}

This way you will get a callback in your activity with pet age. Note: I have used Kotlin and java here. But this will give you an idea to solve your issue.

Let me know if you need further help.

CodePudding user response：

You can use an interface for getting your Pet object in the activity.

Create an interface in your RequesterAdapter class

  public interface ItemClickListener {
        void onItemClick(Pet pet);
  }

Change RequestAdapter constructor to accept ItemClickListener and assign it to itemClickListener object.

private ItemClickListener itemClickListener;
public RequesterAdapter(Context context, List<Pet> requestersList, ItemClickListener itemClickListener) {
            super(context, -1, requestersList);
            this.context = context;
            this.requestersList = requestersList;
            this.itemClickListener = itemClickListener;
        }

Implement this interface in MainActivity and override onItemClick

public class MainActivity extends AppCompatActivity implements RequesterAdapter.ItemClickListener {
    @Override
    public void onItemClick(Pet pet) {
        // execute your database operations
    }
}

Trigger onItemClick method, from requestAcceptButton clickListener

requestAcceptButton.setOnClickListener(view -> itemClickListener.onItemClick(currentPetPosition));