1.导入依赖

implementation 'com.github.CymChad:BaseRecyclerViewAdapterHelper:2.9.35'

2.写一个Layout布局装载RecyclerView

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical"android:background="#F2F1F6"style="@style/xxx"><!-- 标题栏 --><RelativeLayout android:id="@+id/title_bar"android:layout_width="match_parent"android:layout_height="@dimen/dimen_titltbar_height"android:layout_gravity="center_vertical"android:background="@drawable/xxx"><ImageViewandroid:id="@+id/backhome"style="@style/xxx" /><TextViewandroid:id="@+id/nfctitle"style="@style/aj_new_title_bar_title_text"android:text="@string/xxx" /></RelativeLayout><Buttonandroid:id="@+id/test_btn"android:text="测试"android:layout_width="wrap_content"android:layout_height="wrap_content"/><!-- 正文 --><androidx.recyclerview.widget.RecyclerViewandroid:id="@+id/product_rv"android:padding="10dp"android:layout_width="match_parent"android:layout_height="wrap_content"/></LinearLayout>

3.Acitivity

public class AllActivity extends AppCompatActivity {private Disposable subscribe;RecyclerView product_rv;@AllArgsConstructorpublic static class Args {int[] viewIdArray;String[] moduleNames;AutoDto[][] autoDtos;}private final static String TAG = "AllActivity";ImageView backhome;Button button;private Unbinder bind;@SuppressLint("CheckResult")@Overrideprotected void onCreate(@Nullable Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity);backhome = findViewById(R.id.backhome);product_rv = findViewById(R.id.product_rv);button = findViewById(R.id.test_btn);subscribe = Observable.fromCallable(() -> {List<ProductCateDto> productList = new LinkedList<>();return productList;}).subscribeOn(Schedulers.io()).observeOn(AndroidSchedulers.mainThread()).subscribe(new Consumer<List<ProductCateDto>>() {@Overridepublic void accept(List<ProductCateDto> productCateDtos) throws Exception {GridRecyclerAdapter adapter = new GridRecyclerAdapter(AllActivity.this, productCateDtos);GridSpacingItemDecoration gridSpacingItemDecoration = new GridSpacingItemDecoration( 13, true);//Grid布局GridLayoutManager gridLayoutManager = new GridLayoutManager(AllActivity.this, 4);product_rv.setLayoutManager(gridLayoutManager);//这里用线性宫格显示 类似于grid viewproduct_rv.setAdapter(adapter);product_rv.addItemDecoration(gridSpacingItemDecoration);product_rv.setClipToPadding(false);DefaultItemAnimator defaultItemAnimator = new DefaultItemAnimator();defaultItemAnimator.setAddDuration(1000);defaultItemAnimator.setRemoveDuration(1000);product_rv.setItemAnimator(defaultItemAnimator);/*** 设置item所占的格子*/gridLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {@Overridepublic int getSpanSize(int position) {return adapter.isHeader(position) ? gridLayoutManager.getSpanCount() : 1;}});button.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View view) {//自己随便设一个随机集合List<ProductCateDto> list = Arrays.asList();Random random = new Random();int i = random.nextInt(2);ProductCateDto productCateDto1 = list.get(i);LinkedList<ProductCateDto> productCateDtos2 = new LinkedList<>(productCateDtos);productCateDtos2.addFirst(productCateDto1);adapter.updateList(productCateDtos2);}});}}, new Consumer<Throwable>() {@Overridepublic void accept(Throwable throwable) throws Exception {Log.e("TAG", "accept: " + throwable.getMessage());}});init();}public void init() {backhome.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View view) {Intent intent = new Intent(AllActivity.this, Activity_other.class);startActivity(intent);startAini(true);finish();}});}/*** Intent Switching animation** @param flag*/public void startAini(boolean flag) {if (flag) {overridePendingTransition(R.anim.push_right_in,R.anim.push_right_out);} else {overridePendingTransition(R.anim.push_left_in, R.anim.push_left_out);}}@Overrideprotected void onDestroy() {super.onDestroy();System.out.println("onDestroy");if (bind != null) {//解绑视图bind.unbind();}if (subscribe != null) {subscribe.dispose();}}
}

4.RecyclerView适配器

public class GridRecyclerAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {public static final Integer HEADER = 0;public static final Integer BODY = 1;private Activity context;List<ProductCateDto> productCateDtoList;public boolean isHeader(int position) {return productCateDtoList.get(position).getType().equals(HEADER);}public void updateList(List<ProductCateDto> newList) {MyDiffCallback<ProductCateDto> diffCallback = new MyDiffCallback<>(this.productCateDtoList, newList);DiffUtil.DiffResult diffResult = DiffUtil.calculateDiff(diffCallback);this.productCateDtoList.clear();this.productCateDtoList.addAll(newList);diffResult.dispatchUpdatesTo(this);}@Overridepublic int getItemViewType(int position) {ProductCateDto productCateDto = productCateDtoList.get(position);return productCateDto.getType();}public GridRecyclerAdapter(Activity context, List<ProductCateDto> productCateDtoList) {this.context = context;this.productCateDtoList = productCateDtoList;}@NonNull@Overridepublic RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {View inflate;if (viewType == HEADER) {inflate = LayoutInflater.from(context).inflate(R.layout.layout_product_category_header, parent, false);return new HeaderViewHolder(inflate);} else {inflate = LayoutInflater.from(context).inflate(R.layout.jmy_grid_item, parent, false);return new BodyViewHolder(inflate);}}@Overridepublic void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {ProductCateDto productCateDto = productCateDtoList.get(position);Integer type = productCateDto.getType();if (type.equals(HEADER)) {HeaderViewHolder headerViewHolder = (HeaderViewHolder) holder;headerViewHolder.title_tv.setText(productCateDto.getHeaderName());} else {BodyViewHolder bodyViewHolder = (BodyViewHolder) holder;bodyViewHolder.iv.setImageResource(productCateDto.getImage());bodyViewHolder.tv.setText(productCateDto.getName());bodyViewHolder.itemView.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View view) {// Handle item clickIntent intent = new Intent(context, productCateDto.getAClass());context.startActivity(intent);startAini(false);context.finish();}});}}/*** Intent Switching animation** @param flag*/public void startAini(boolean flag) {if (flag) {context.overridePendingTransition(R.anim.push_right_in,R.anim.push_right_out);} else {context.overridePendingTransition(R.anim.push_left_in, R.anim.push_left_out);}}@Overridepublic int getItemCount() {return productCateDtoList.size();}public static class HeaderViewHolder extends RecyclerView.ViewHolder {TextView title_tv;public HeaderViewHolder(@NonNull View itemView) {super(itemView);title_tv = itemView.findViewById(R.id.title_tv);}}public static class BodyViewHolder extends RecyclerView.ViewHolder {ImageView iv;TextView tv;public BodyViewHolder(@NonNull View itemView) {super(itemView);iv = itemView.findViewById(R.id.iv_item);tv = itemView.findViewById(R.id.tv_item);}}}

5.自动调整item间距

public class GridSpacingItemDecoration extends RecyclerView.ItemDecoration {private int spanCount;private int spacing;private boolean includeEdge;public GridSpacingItemDecoration(int spacing, boolean includeEdge) {this.spacing = spacing;this.includeEdge = includeEdge;}@Overridepublic void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {int position = parent.getChildAdapterPosition(view); // item positionRecyclerView.Adapter adapter = parent.getAdapter();int itemViewType = adapter.getItemViewType(position);if (itemViewType==GridRecyclerAdapter.HEADER){spanCount=4;}else {spanCount=1;}int column = position % spanCount; // item columnif (includeEdge) {outRect.left = spacing - column * spacing / spanCount;outRect.right = (column + 1) * spacing / spanCount;} else {outRect.left = column * spacing / spanCount;outRect.right = spacing - (column + 1) * spacing / spanCount;}}
}

6.BaseEntity

import lombok.Getter;
import lombok.Setter;public class BaseEntity {@Getter@Setterprivate String id;
}

都是代码，不解释了