Android RecyclerView：将布局文件 LIST 更改为 GRID onOptionItemSelected

Question

我正在开发一个 Android 在线购物应用程序。我使用 RecyclerView 为产品列表创建了以下视图，因为我想在选择选项菜单项 时更改视图 :

我创建了以下名为 ProductAdapter 的 适配器，因为我已经在 onCreateViewHolder 中实现了更改布局的代码，用于根据布尔值选择布局文件.

适配器代码ProductAdapter:

    /***
     * ADAPTER for Product to binding rows in List
     */
    private class ProductAdapter extends RecyclerView.Adapter<ProductAdapter.ProductRowHolder> {

        private List<Product> productList;

        private Context mContext;

        public ProductAdapter(Context context, List<Product> feedItemList) {
            this.productList = feedItemList;
            this.mContext = context;
        }

        @Override
        public ProductRowHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
            View v = LayoutInflater.from(viewGroup.getContext()).inflate(isProductViewAsList ? R.layout.product_row_layout_list : R.layout.product_row_layout_grid, null);
            ProductRowHolder mh = new ProductRowHolder(v);
            return mh;
        }

        @Override
        public void onBindViewHolder(ProductRowHolder  productRowHolder, int i) {
            Product prodItem = productList.get(i);

//            Picasso.with(mContext).load(feedItem.getName())
//                    .error(R.drawable.ic_launcher)
//                    .placeholder(R.drawable.ic_launcher)
//                    .into(productRowHolder.thumbnail);


            double price = prodItem.getPrice();
            double discount = prodItem.getDiscount();
            double discountedPrice = price - (price * discount / 100);

            String code = "";
            if(prodItem.getCode() != null)
                code = "[" + prodItem.getCode() + "] ";

            productRowHolder.prodIsNewView.setVisibility(prodItem.getIsNew() == 1 ? View.VISIBLE : View.INVISIBLE);
            productRowHolder.prodNameView.setText(code + prodItem.getName());
            productRowHolder.prodOriginalRateView.setText("Rs." + new BigDecimal(price).setScale(2,RoundingMode.DOWN));
            productRowHolder.prodDiscView.setText("" + new BigDecimal(discount).setScale(2,RoundingMode.DOWN) + "% off");
            productRowHolder.prodDiscRateView.setText("Rs." + new BigDecimal(discountedPrice).setScale(2,RoundingMode.DOWN));

            productRowHolder.prodOriginalRateView.setPaintFlags(productRowHolder.prodOriginalRateView.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
        }

        @Override
        public int getItemCount() {
            return (null != productList ? productList.size() : 0);
        }

        public class ProductRowHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
            //Declaration of Views

            public ProductRowHolder(View view) {
                super(view);

                view.setOnClickListener(this);

                //Find Views
            }

            @Override
            public void onClick(View view) {
               //Onclick of row
            }
        }
    }

之后，我完成了将 RecyclerView 布局从 List 更改为 Grid 以及 onOptionsItemSelected 中反之亦然的代码，我在这里调用 mAdapter.notifyDataSetChanged();所以它会再次调用适配器并更改值。

onOptionsItemSelected:

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        switch (id) {
            case R.id.action_settings:
                return true;
            case android.R.id.home:
                finish();
                break;
            case R.id.product_show_as_view:
                isProductViewAsList = !isProductViewAsList;
                supportInvalidateOptionsMenu();
                mRecyclerView.setLayoutManager(isProductViewAsList ? new LinearLayoutManager(this) : new GridLayoutManager(this, 2));
                mAdapter.notifyDataSetChanged();
                break;
        }

        return super.onOptionsItemSelected(item);
    }

我取得了一些成功，例如：

Grid 布局的图像：

List 布局的图像：

但现在当我滚动然后更改视图时显示如：

Grid布局：

List布局：

不知道为什么滚动后会这样。有没有其他方法可以像这样改变视图。

Today i just saw that this problem is because of ImageView, without it working perfectly.

请帮忙，你的帮助将不胜感激。

Answer 1

我找到了 activity 开头的解决方案我设置了 LinearLayoutManager 如下：

mLayoutManager = new LinearLayoutManager(this);
mProductListRecyclerView.setLayoutManager(mLayoutManager);

之后onOptionsItemSelected写成：

case R.id.menu_product_change_view:
     isViewWithCatalog = !isViewWithCatalog;
     supportInvalidateOptionsMenu();
     //loading = false;
     mProductListRecyclerView.setLayoutManager(isViewWithCatalog ? new LinearLayoutManager(this) : new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL));
     mProductListRecyclerView.setAdapter(mAdapter);
     break;

并在 onCreateViewHolder 中更改视图，例如：

@Override
public ProductRowHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
    View v = LayoutInflater.from(viewGroup.getContext()).inflate(isViewWithCatalog ? R.layout.product_row_layout_list : R.layout.product_row_layout_grid, null);
    ProductRowHolder mh = new ProductRowHolder(v);
    return mh;
}

从开始到结束，您必须管理 isViewWithCatalog 变量以首先显示哪个布局。

Answer 2

我通过在更改布局管理器后再次将适配器设置为 RecyclerView 解决了这个问题。

listView.setLayoutManager(new LinearLayoutManager(this));
listView.setAdapter(adapter);

Answer 3

我认为在滚动并改回网格视图后，不会重新创建第一项。我通过覆盖 getItemViewType() 并相应地在 onCreateViewHolder 中扩充布局文件来解决这个问题。

Answer 4

在这个 SDK samples 中有一个完整的示例，但是它为两个 LayoutManager 使用一个布局文件

为了在切换布局时保持滚动位置，他们使用了这个功能

public void setRecyclerViewLayoutManager(LayoutManagerType layoutManagerType) {
    int scrollPosition = 0;

    // If a layout manager has already been set, get current scroll position.
    if (mRecyclerView.getLayoutManager() != null) {
        scrollPosition = ((LinearLayoutManager) mRecyclerView.getLayoutManager())
                .findFirstCompletelyVisibleItemPosition();
    }

    switch (layoutManagerType) {
        case GRID_LAYOUT_MANAGER:
            mLayoutManager = new GridLayoutManager(getActivity(), SPAN_COUNT);
            mCurrentLayoutManagerType = LayoutManagerType.GRID_LAYOUT_MANAGER;
            break;
        case LINEAR_LAYOUT_MANAGER:
            mLayoutManager = new LinearLayoutManager(getActivity());
            mCurrentLayoutManagerType = LayoutManagerType.LINEAR_LAYOUT_MANAGER;
            break;
        default:
            mLayoutManager = new LinearLayoutManager(getActivity());
            mCurrentLayoutManagerType = LayoutManagerType.LINEAR_LAYOUT_MANAGER;
    }

    mRecyclerView.setLayoutManager(mLayoutManager);
    mRecyclerView.scrollToPosition(scrollPosition);
}

Android RecyclerView：将布局文件 LIST 更改为 GRID onOptionItemSelected

Android RecyclerView: Change layout file LIST to GRID onOptionItemSelected

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