java 在 RecyclerView 或 Grouping Recyclerview 项目中按组划分元素，例如按日期

Divide elements on groups in RecyclerView or Grouping Recyclerview items ,say by date

提问by kinsley kajiva

i want to group my android RecyclerViewitems with a header made based on date like this:

我想将我的 androidRecyclerView项目与基于日期的标题进行分组，如下所示：

    1 week ago
    - item
    - item
    - item
    - item
    2 weeks ago
    - item
    - item
    - item

that sort of thing or grouping based on some element.

基于某些元素的那种事情或分组。

回答by kinsley kajiva

Here is a solution i came by with the aid of alot research over the net and this blog link as well Kartikey Kuswhahaso its not all my credit but i just want to give more clarity to it. below is the code: create the following files:PojoOfJsonArray,MainActivity, ListItem,GeneralItem,DateItem, Adapter

这是我通过网络和此博客链接以及Kartikey Kuswhaha的大量研究得出的解决方案，所以这不是我的全部功劳，但我只是想更清楚地说明它。下面是代码：创建以下文件：PojoOfJsonArray、MainActivity、ListItem、GeneralItem、DateItem、Adapter

PojoOfJsonArray.java -this file wil represent your POJO class or whatever pojo you got going on in your app so:

PojoOfJsonArray.java - 该文件将代表您的 POJO 类或您在应用程序中使用的任何 pojo，因此：

 public class PojoOfJsonArray  {

    public PojoOfJsonArray(String name, String date) {
        this.name = name;
        this.date = date;
    }

    private String name,date;


    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getDate() {
        return date;
    }

    public void setDate(String date) {
        this.date = date;
    }
}

MainActivity.java this is the activity that you will use to implement you recyclerview :

MainActivity.java 这是您将用于实现回收视图的活动：

public class MainActivity extends AppCompatActivity {
    private List<PojoOfJsonArray> myOptions = new ArrayList<>();
    List<ListItem> consolidatedList = new ArrayList<>();

    private RecyclerView mRecyclerView;
    private Adapter adapter;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mRecyclerView = (RecyclerView) findViewById(R.id.recyclerview);
        mRecyclerView.setHasFixedSize(true);

        myOptions.add(new PojoOfJsonArray("name 1", "2016-06-21"));
        myOptions.add(new PojoOfJsonArray("name 2", "2016-06-05"));
        myOptions.add(new PojoOfJsonArray("name 2", "2016-06-05"));
        myOptions.add(new PojoOfJsonArray("name 3", "2016-05-17"));
        myOptions.add(new PojoOfJsonArray("name 3", "2016-05-17"));
        myOptions.add(new PojoOfJsonArray("name 3", "2016-05-17"));
        myOptions.add(new PojoOfJsonArray("name 3", "2016-05-17"));
        myOptions.add(new PojoOfJsonArray("name 2", "2016-06-05"));
        myOptions.add(new PojoOfJsonArray("name 3", "2016-05-17"));

        HashMap<String, List<PojoOfJsonArray>> groupedHashMap = groupDataIntoHashMap(myOptions);


        for (String date : groupedHashMap.keySet()) {
            DateItem dateItem = new DateItem();
            dateItem.setDate(date);
            consolidatedList.add(dateItem);


            for (PojoOfJsonArray pojoOfJsonArray : groupedHashMap.get(date)) {
                GeneralItem generalItem = new GeneralItem();
                generalItem.setPojoOfJsonArray(pojoOfJsonArray);//setBookingDataTabs(bookingDataTabs);
                consolidatedList.add(generalItem);
            }
        }


        adapter = new Adapter(this, consolidatedList);
        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
        mRecyclerView.setLayoutManager(layoutManager);
        mRecyclerView.setAdapter(adapter);


    }

    private HashMap<String, List<PojoOfJsonArray>> groupDataIntoHashMap(List<PojoOfJsonArray> listOfPojosOfJsonArray) {

        HashMap<String, List<PojoOfJsonArray>> groupedHashMap = new HashMap<>();

        for (PojoOfJsonArray pojoOfJsonArray : listOfPojosOfJsonArray) {

            String hashMapKey = pojoOfJsonArray.getDate();

            if (groupedHashMap.containsKey(hashMapKey)) {
                // The key is already in the HashMap; add the pojo object
                // against the existing key.
                groupedHashMap.get(hashMapKey).add(pojoOfJsonArray);
            } else {
                // The key is not there in the HashMap; create a new key-value pair
                List<PojoOfJsonArray> list = new ArrayList<>();
                list.add(pojoOfJsonArray);
                groupedHashMap.put(hashMapKey, list);
            }
        }


        return groupedHashMap;
    }

}

the myOptions is where one would use to feed your data into. ListItem.java

myOptions 是人们用来将数据输入的地方。 列表项.java

public abstract class ListItem {

    public static final int TYPE_DATE = 0;
    public static final int TYPE_GENERAL = 1;

    abstract public int getType();
}

GeneralItem.java

通用项目.java

public class GeneralItem extends ListItem {
    private PojoOfJsonArray pojoOfJsonArray;

    public PojoOfJsonArray getPojoOfJsonArray() {
        return pojoOfJsonArray;
    }

    public void setPojoOfJsonArray(PojoOfJsonArray pojoOfJsonArray) {
        this.pojoOfJsonArray = pojoOfJsonArray;
    }

    @Override
    public int getType() {
        return TYPE_GENERAL;
    }


}

DateItem.java

日期项.java

public class DateItem extends ListItem {

    private String date;

    public String getDate() {
        return date;
    }

    public void setDate(String date) {
        this.date = date;
    }

    @Override
    public int getType() {
        return TYPE_DATE;
    }
}

Adapter.java this adapter is for the recyclerview if your not well informed on how to make simple sectioned recyclerview then i suggest you read on those and be good in the area because this is abit more tricky anyways:

Adapter.java 这个适配器是为 recyclerview 准备的，如果你对如何制作简单的分段 recyclerview 不是很了解，那么我建议你阅读这些内容并在该领域做得好，因为无论如何这有点棘手：

public class Adapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {


    private Context mContext;
    List<ListItem> consolidatedList = new ArrayList<>();

    public Adapter(Context context, List<ListItem> consolidatedList) {
        this.consolidatedList = consolidatedList;
        this.mContext = context;


    }


    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent,  int viewType) {

        RecyclerView.ViewHolder viewHolder = null;
        LayoutInflater inflater = LayoutInflater.from(parent.getContext());

        switch (viewType) {

            case ListItem.TYPE_GENERAL:
                View v1 = inflater.inflate(R.layout.items, parent,
                        false);
                viewHolder = new GeneralViewHolder(v1);
                break;

            case ListItem.TYPE_DATE:
                View v2 = inflater.inflate(R.layout.itemsh, parent, false);
                viewHolder = new DateViewHolder(v2);
                break;
        }

        return viewHolder;
    }

    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder viewHolder, int position) {

        switch (viewHolder.getItemViewType()) {

            case ListItem.TYPE_GENERAL:

                GeneralItem generalItem   = (GeneralItem) consolidatedList.get(position);
                GeneralViewHolder generalViewHolder= (GeneralViewHolder) viewHolder;
                generalViewHolder.txtTitle.setText(generalItem.getPojoOfJsonArray().getName());

                break;

            case ListItem.TYPE_DATE:
                DateItem dateItem = (DateItem) consolidatedList.get(position);
                DateViewHolder dateViewHolder = (DateViewHolder) viewHolder;

                dateViewHolder.txtTitle.setText(dateItem.getDate());
                // Populate date item data here

                break;
        }
    }





    // ViewHolder for date row item
    class DateViewHolder extends RecyclerView.ViewHolder {
        protected TextView txtTitle;

        public DateViewHolder(View v) {
            super(v);
            this.txtTitle = (TextView) v.findViewById(R.id.txt);

        }
    }

    // View holder for general row item
    class GeneralViewHolder extends RecyclerView.ViewHolder {
        protected TextView txtTitle;

        public GeneralViewHolder(View v) {
            super(v);
            this.txtTitle = (TextView) v.findViewById(R.id.txt);

        }
    }

    @Override
    public int getItemViewType(int position) {
        return consolidatedList.get(position).getType();
    }

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

}

and this has two layout being used . thus all

这有两种布局正在使用。因此所有

回答by Gustavo

You can use the library SectionedRecyclerViewAdapterto easily group your data into sections and add a header to each section.

您可以使用库SectionedRecyclerViewAdapter轻松地将数据分组为多个部分，并为每个部分添加标题。

First create a Section class:

首先创建一个Section类：

class MySection extends StatelessSection {

    String title;
    List<String> list;

    public MySection(String title, List<String> list) {
        // call constructor with layout resources for this Section header, footer and items 
        super(R.layout.section_header, R.layout.section_item);

        this.title = title;
        this.list = list;
    }

    @Override
    public int getContentItemsTotal() {
        return list.size(); // number of items of this section
    }

    @Override
    public RecyclerView.ViewHolder getItemViewHolder(View view) {
        // return a custom instance of ViewHolder for the items of this section
        return new MyItemViewHolder(view);
    }

    @Override
    public void onBindItemViewHolder(RecyclerView.ViewHolder holder, int position) {
        MyItemViewHolder itemHolder = (MyItemViewHolder) holder;

        // bind your view here
        itemHolder.tvItem.setText(list.get(position));
    }

    @Override
    public RecyclerView.ViewHolder getFooterViewHolder(View view) {
        return new MyFooterViewHolder(view);
    }

    @Override
    public void onBindFooterViewHolder(RecyclerView.ViewHolder holder) {
        MyFooterViewHolder footerHolder = (MyFooterViewHolder) holder;

        // bind your footer view here
        footerHolder.tvItem.setText(title);
    }
}

Then you set up the RecyclerView with your Sections:

然后你用你的部分设置 RecyclerView：

// Create an instance of SectionedRecyclerViewAdapter 
SectionedRecyclerViewAdapter sectionAdapter = new SectionedRecyclerViewAdapter();

// Create your sections with the list of data for each year
MySection section1 = new MySection("1 week ago", week1data);
MySection section2 = new MySection("2 weeks ago", week2data);

// Add your Sections to the adapter
sectionAdapter.addSection(section1);
sectionAdapter.addSection(section2);

// Set up your RecyclerView with the SectionedRecyclerViewAdapter
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
recyclerView.setAdapter(sectionAdapter);

回答by Akshay Chordiya

I solved this problem with the help of Section RecyclerView libraryand using these functions (Gist)to check if date is "Today", "Yesterday", and so on.

我在Section RecyclerView 库的帮助下解决了这个问题，并使用这些函数 (Gist)检查日期是否为“今天”、“昨天”等。

I'm hoping to build a end-to-end library for this. Let me know if your interested then I can build and open-source it.

我希望为此构建一个端到端的库。如果您有兴趣，请告诉我，然后我可以构建并开源它。

Sample screenshot below:

下面的示例截图：