Question

我在RecyclerView适配器中定义了一个方法，并希望从MainActivity中调用它，但我不能。请指导我。

我的主要活动

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    GetDataAdapter1 = new ArrayList<>();
    recyclerView = (RecyclerView) findViewById(R.id.recyclerView1);
    recyclerViewlayoutManager = new LinearLayoutManager(this);
    recyclerView.setLayoutManager(recyclerViewlayoutManager);
    JSON_DATA_WEB_CALL();
    recyclerViewadapter = new RecyclerViewAdapter(MainActivity.this, GetDataAdapter1, this);

    recyclerView.setAdapter(recyclerViewadapter);
    recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {                super.onScrolled(recyclerView, dx, dy);
            LinearLayoutManager manager = (LinearLayoutManager) recyclerView.getLayoutManager();

            int firstVisible = manager.findFirstVisibleItemPosition();
            int lastVisible = manager.findLastVisibleItemPosition();
            Log.i("TAG", "onScrolled: " + firstVisible);
            Log.i("TAG", "Last Index: " + lastVisible);
            recyclerViewadapter.changeItem(firstVisible,lastVisible);
        }
    });

我的适配器

@Override
public int getItemCount() {

    return getDataAdapter.size();
}

public void changeItem(int position){
    firstVisible = position;
    notifyItemChanged(firstVisible);
    notifyDataSetChanged();
}


class ViewHolder extends RecyclerView.ViewHolder{

    public TextView IdTextView;
    public TextView NameTextView;
    public TextView PhoneNumberTextView;
    public TextView SubjectTextView;

我想从MainActivity调用此changeItem

Answer 1

您使用一个参数声明了该函数：

public void changeItem(int position)

但你用2个参数调用它：

recyclerViewadapter.changeItem(firstVisible,lastVisible);

我也很确定在这些方面：

firstVisible = position;
notifyItemChanged(firstVisible);

firstVisible不在范围内。您应该了解参数和范围的工作原理。

在适配器中定义方法并从MainActivity调用

1 个答案: