滚动时更新recyclerview的位置(android) [英] update position of recyclerview when scrolling (android)

问题描述

如何更新滚动位置.现在，每次我单击项目时，位置都会更新.我想在每次滚动时更新位置.我想做的是拥有一个文本视图，当滚动浏览各个项目时，该视图将得到更新.

How can i update position on scroll. right now the position gets updated every time i click on item. i want to update the position every time i scroll. What i wanna do is have a text view which will get updated when scrolling through the items.

recyclerView.addOnItemTouchListener(new GalleryAdapter.RecyclerTouchListener(this, recyclerView, new GalleryAdapter.ClickListener()
            {

                @Override
                public void onClick(View view, int position) {

                    Intent intent = new Intent(mainActivityCarasoul.this, PDFViewerActivity.class);
                    intent.putExtra(PDFViewerActivity.TAG, books.get(position));
                    intent.putExtra("from", "mainActivityCarasoul");
                    startActivity(intent);
                }
                @Override
                public void onLongClick(View view, int position) {
                }
            }));

            recyclerView.addOnScrollListener(new CenterScrollListener());

            recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
                @Override
                public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
                    super.onScrollStateChanged(recyclerView, newState);
                   // title.setText(books.get(position).getName());

                }
            });

推荐答案

使用此方法，您将必须在您的活动中保持一个previousPosition，而在您的适配器类中必须保持一个selectedItem，因为int会初始化previousPoistion = -1；并selectedPosition = 1;

use this, you will have to maintain a previousPosition in your activity and in your adapter class a selectedItem as int intialize previousPoistion=-1; and selectedPosition=1;

 @Override
        public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
            super.onScrollStateChanged(recyclerView, newState);
            switch (newState) {
                case 0:
                    int pos = linearLayoutManager1.findLastVisibleItemPosition();
                    yourAdapter.selectedPosition = pos - 1;
                    previousPosition = pos - 1;
                    yourTextView.setText(yourLIst.get(pos-1));
                    break;
            }
        }
    });

并在适配器的onBindView容器中

and in your onBindView Holder of adapter

@Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int position) {
if (position == selectedPosition) {
             //do what you want when selected
            } 
}

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