如何在单击按钮时在recyclerview中添加元素？

Question

I have screen where I need to display three elements in a recyclerview on the click of a button.

In my Activity where I have my recyclerview, I want to know the logic which will enable me to add items to my recyclerview adapter on the click of my button. Here is the code segment of my activity :

List<OustChatModel> chatList;
chatList=new ArrayList<>();
    chatList.add(new OustChatModel(1,
            "Sample Image Card",
            R.drawable.app_icon,
            "sample description"));
    chatList.add(new OustChatModel(2,
            "Sample Video Card",
            "Sample Video description",
            R.drawable.app_icon
            ));
    chatList.add(new OustChatModel(3,
            "Textcard title",
            "Textcard description"
            ));
    final OustChatAdapter adapter = new OustChatAdapter(this, chatList,CourseChatActivity.this);


    proceedChat.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

                recyclerView.setAdapter(adapter);


        }
    });

When I execute this code, all three elements of my arraylist apper on the click of a button. I want the elements to appear one below the other only after the click of the button.

Pls. do suggest suitable logic.

Thanks in advance.

Answer 1

Try this: code

chatList=new ArrayList<>();
int clickAmount = 0;
chatList.add(new OustChatModel(1,
        "Sample Image Card",
        R.drawable.app_icon,
        "sample description"));
chatList.add(new OustChatModel(2,
        "Sample Video Card",
        "Sample Video description",
        R.drawable.app_icon
        ));
chatList.add(new OustChatModel(3,
        "Textcard title",
        "Textcard description"
        ));
final OustChatAdapter adapter = new OustChatAdapter(this, chatList,CourseChatActivity.this);


proceedChat.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {

            newList =new ArrayList<>();
            if(clickAmount < 3){
            newList.add(clickAmount)
            }
            recyclerView.setAdapter(adapter, newList);
            clickAmount ++;

    }
});

Every time you click add another element to the arraylist, and then display that list instead of the one one with all 3 elements with it.

Answer 2

To make each element appear one after the other when you click on the button (meaning 3 clicks):

// Create the empty array list object
List<OustChatModel> emptyList = new ArrayList<>();

// Create a second array list containing objects
List<OustChatModel> chatList = new ArrayList<>();
chatList.add(new OustChatModel(1,
            "Sample Image Card",
            R.drawable.app_icon,
            "sample description"));

chatList.add(new OustChatModel(2,
            "Sample Video Card",
            "Sample Video description",
            R.drawable.app_icon));

chatList.add(new OustChatModel(3,
            "Textcard title",
            "Textcard description"));

// Pass empty list into the adapter
final OustChatAdapter adapter = new OustChatAdapter(this, emptyList, CourseChatActivity.this);

// set the adapter for the recycler view
recyclerView.setAdapter(adapter);

// counter to track number of clicks
int numberOfClicks = 0;

proceedChat.setOnClickListener(new View.OnClickListner() {
    @Override
    public void onClick(View view){
        if (numberOfClicks < chatList.length()) {
            adapter.addItem(chatList.get(numberOfClicks));
            numberOfClicks++;
        }
    }
});

In your OustChatAdapter class you'll have this method:

public void addItem(OustChatModel model){
   chatList.add(model);
   notifyDataSetChanged(); // This is to notify the adapter that the data in the recyclerview has been modified.
} 

Sidenote: My guess is the activity you're in is CourseChatActivity . Correct me if I'm wrong but if that's the case, there is no need to pass an instance of the class using this , then pass the CourseChatActivity.this after into the OustChatAdapter . It would be better set the adapter constructor to use:

new OustChatAdapter(this, emptyList)