How to select all items which listed in recyclerview?

Question

I have list of items inside of recyclerview, and they are multiple selectable.

I want to have select button to select all, and if selected deselect all. I didn't see any option to iterate through RecyclerView.Adapter to do that. How can I implement that?

Thank you.

Answer 1

Try to maintain Selected item list and list of items in Adapter,

When you select "Select All" button, just add all item in selected item list and call notifyDataSetChanged

Just a sudo code

class adapter {
    ArrayList<Item> selected = new ArrayList<Item>();
    ArrayList<Item> items = new ArrayList<Item>();

    public void selecteAll() {
        selected.clear();
        selected.addAll(items);
        notifyDataSetChanged();
    }

    public void clearAll() {
        selected.clear();
        notifyDataSetChanged();
    }

    public void bindView() {
        Item item = items.get(position);

        if(selected.contains(item) {
            // Do selected action
        } else {
           // Non selecetd ctions
        }
    }

}

Answer 2

In my case,

Step - 1 :- first globally initialize flag in activity class

boolean flagSelectAll = false;

Step - 2 :- Then set below code in Onclick of Button

@OnClick(R.id.btnSelectAll)
public void setBtnSelectAll(View view){
    for (int i=0;i<dMyItemLists.size();i++){
        if (dMyItemLists.get(i).isSelected()){
            flagSelectAll = true;
            dMyItemListAdapter.selectAllItem(false);
            dMyItemListAdapter.notifyDataSetChanged();
        }
        else {
            dMyItemListAdapter.selectAllItem(true);
            dMyItemListAdapter.notifyDataSetChanged();
        }
        break;
    }
}

Step - 3 :- Then create method selectAllItem in recyclerview's adpater class like below :

public void selectAllItem(boolean isSelectedAll) {
        try {
            if (itemList != null) {
                for (int index = 0; index < itemList.size(); index++) {
                    itemList.get(index).setSelected(isSelectedAll);
                }
            }
            notifyDataSetChanged();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }