Android RecyclerView 实现 GridView ，并实现点击效果及方向位置的显示

效果图

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一、引入

 implementation 'com.github.CymChad:BaseRecyclerViewAdapterHelper:2.9.30'

二、使用步骤

1.Adapter

public class UnAdapter extends BaseQuickAdapter<UnBean.ResultBean, BaseViewHolder> {private int selectedPosition = RecyclerView.NO_POSITION; // 用于记录当前选中的位置private int lastSelectedPosition = RecyclerView.NO_POSITION; // 上一次选中的位置private int spanCount = 4; // 每行显示的列数// 处理item点击事件的方法public void onItemClick(int position) {// 如果点击的是当前选中的item，则不执行任何操作（或者执行特定的操作）if (position == selectedPosition) {return;}// 更新选中状态if (selectedPosition != RecyclerView.NO_POSITION) {// 如果之前有选中的item，先通知适配器刷新它，以恢复默认背景notifyItemChanged(selectedPosition);}// 更新选中位置lastSelectedPosition = selectedPosition;selectedPosition = position;// 通知适配器刷新新选中的itemnotifyItemChanged(selectedPosition);}// （可选）如果需要，可以添加一个方法来处理取消选中item的情况private void deselectItem(int position) {if (position == selectedPosition) {selectedPosition = RecyclerView.NO_POSITION;}}public  UnAdapter(int layoutResId, @Nullable List<UnBean.ResultBean> data) {super(layoutResId, data);}@SuppressLint("ResourceAsColor")@Overrideprotected void convert(BaseViewHolder helper, UnBean.ResultBean item) {ImageView fx_rightImg = helper.getView(R.id.fx_right_img);ImageView fx_leftImg = helper.getView(R.id.fx_left_img);LinearLayout fx_upLayout = helper.getView(R.id.fx_up_layout);LinearLayout bgLayout = helper.getView(R.id.bg_layout);// 根据是否选中来设置背景if (helper.getLayoutPosition() == selectedPosition) {bgLayout.setBackgroundResource(R.drawable.shape_blue_8);helper.setTextColor(R.id.cd_tv, mContext.getColor(R.color.white));} else if (helper.getLayoutPosition() == lastSelectedPosition && lastSelectedPosition != RecyclerView.NO_POSITION) {bgLayout.setBackgroundResource(R.drawable.shape_bg_position_sel);helper.setTextColor(R.id.cd_tv, mContext.getColor(R.color.blue_text));} else {bgLayout.setBackgroundResource(R.drawable.shape_bg_position_sel);helper.setTextColor(R.id.cd_tv, mContext.getColor(R.color.blue_text));}// 设置点击监听器（注意：这里应该在ViewHolder的构造函数中设置，以避免重复设置）// 但为了简化示例，这里直接在convert中设置（不推荐）bgLayout.setOnClickListener(v -> {onItemClick(helper.getPosition());});// 计算当前项位于哪一行int position = helper.getAdapterPosition(); // 获取当前项的索引int row = position / spanCount; // 整数除法得到当前行号（注意：这里假设没有头部或脚部项）// 计算当前项在当前行的列索引（从0开始）int column = position % spanCount;// 判断是否是每行的首项boolean isFirstItemInRow = column == 0;// 判断是否是每行的尾项// 注意：这里的判断需要考虑是否是最后一行且不是整除spanCount的情况boolean isLastItemInRow = (position + 1) % spanCount == 0 || position == getItemCount() - 1;// 或者更精确地判断尾项（仅当当前项不是最后一行的唯一项时才需要额外检查）boolean isLastItemInRowPrecise = (position + 1) % spanCount == 0 ||(position == getItemCount() - 1 && position % spanCount != spanCount - 1);// 判断当前项是否为列表中的最后一位boolean isLastItemInList = position == getItemCount() - 1;// 判断行数的奇偶性if (row % 2 == 0) {fx_rightImg.setVisibility(View.VISIBLE);if (isFirstItemInRow) {fx_upLayout.setVisibility(View.GONE);}if (isLastItemInRowPrecise) {fx_upLayout.setVisibility(View.VISIBLE);fx_rightImg.setVisibility(View.GONE);}} else {fx_leftImg.setVisibility(View.GONE);fx_rightImg.setVisibility(View.VISIBLE);fx_upLayout.setVisibility(View.GONE);if (isFirstItemInRow) {fx_upLayout.setVisibility(View.VISIBLE);}if (isLastItemInRowPrecise) {fx_upLayout.setVisibility(View.GONE);fx_leftImg.setVisibility(View.GONE);}}// 根据是否为最后一位的逻辑来设置UIif (isLastItemInList) {fx_upLayout.setVisibility(View.GONE);fx_rightImg.setVisibility(View.GONE);}helper.setText(R.id.cd_tv, item.getTrain());}}

2. item_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="@dimen/dimen_120"android:layout_height="@dimen/dimen_80"android:layout_marginLeft="@dimen/dimen_15"android:orientation="vertical"android:padding="@dimen/dimen_5"><LinearLayoutandroid:layout_width="match_parent"android:layout_height="@dimen/dp_40"android:orientation="horizontal"><LinearLayoutandroid:id="@+id/bg_layout"android:layout_width="0dp"android:layout_height="match_parent"android:layout_weight="1"android:gravity="center"><TextViewandroid:id="@+id/cd_tv"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="G2519"android:textColor="@color/c_3681ff" /></LinearLayout><LinearLayoutandroid:layout_width="0dp"android:layout_height="match_parent"android:layout_weight="1"android:gravity="center"><ImageViewandroid:id="@+id/fx_right_img"android:layout_width="@dimen/dimen_15"android:layout_height="@dimen/dimen_15"android:background="@drawable/icon_fx_right"android:visibility="gone" /><ImageViewandroid:id="@+id/fx_left_img"android:layout_width="@dimen/dimen_15"android:layout_height="@dimen/dimen_15"android:background="@drawable/icon_fx_left"android:visibility="gone" /></LinearLayout></LinearLayout><LinearLayoutandroid:id="@+id/fx_up_layout"android:layout_width="match_parent"android:layout_height="@dimen/dp_40"android:gravity="center_vertical"android:visibility="gone"><ImageViewandroid:layout_width="@dimen/dimen_15"android:layout_height="@dimen/dimen_15"android:layout_marginLeft="@dimen/dimen_25"android:background="@drawable/icon_fx_up" /></LinearLayout></LinearLayout>

3.应用

 fromAssets = ReadAsUtil.getFromAssets(this, "UnList.json");unBean = new Gson().fromJson(fromAssets, UnBean.class);unList = unBean.getResult();gridLayoutManager = new GridLayoutManager(this, 4);cdLv.setLayoutManager(gridLayoutManager);unAdapter = new UnAdapter(R.layout.item_layout, unList);cdLv.setAdapter(unAdapter);unAdapter.notifyDataSetChanged();

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总结

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