RecyclerView不在ViewPager（Fragment）中更新

Question

美好的一天！

我很难在片段内刷新我的recyclerview值。 这是我的设置：

1. 活动 - ＆gt; MenuItem选项，用于在指定片段中添加值

   2. 片段 - ＆gt;显示当前数据（RecyclerView）; RecyclerViews / Adapters的通货膨胀

我的问题是，当我添加一个新项目时，片段没有更新recyclerview数据，我需要点击或滑动到其他片段并返回片段以刷新recyclerviews。

这是我在活动类中添加新项目对话框：

 private void createPricePerSackDialog() {

    ArrayAdapter<CharSequence> ppsCoconutVarietyAdapter, ppsCoconutSizeAdapter, ppsProductTypeAdapter;

    AlertDialog.Builder builder= new AlertDialog.Builder(this);
    LayoutInflater inflater= this.getLayoutInflater();
    final  View customPricepersackView= inflater.inflate(R.layout.priceper_sack,null);
    builder.setView(customPricepersackView);

    ppsNumberOfTree= (EditText)customPricepersackView.findViewById(R.id.pricepersack_numberoftrees);
    numberOfFruits= (EditText)customPricepersackView.findViewById(R.id.pricepersack_numberoffruits);
    numberOfSack= (EditText)customPricepersackView.findViewById(R.id.pricepersack_numberofsac_editext);
    priceperSack= (EditText)customPricepersackView.findViewById(R.id.pricepersack_pricepersack_editext);

    ppsCoconutVariety= (Spinner)customPricepersackView.findViewById(R.id.pricepersack_coconutVariety_spinner);
    ppsFruitsSize= (Spinner)customPricepersackView.findViewById(R.id.pricepersack_fruitsize_spinner);
    ppsProductType= (Spinner)customPricepersackView.findViewById(R.id.pricepersack_productType_spinner);


    ppsCoconutVarietyAdapter= ArrayAdapter.createFromResource(this,R.array.coconut_varieties, android.R.layout.simple_spinner_item);
    ppsCoconutVarietyAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    ppsCoconutVariety.setAdapter(ppsCoconutVarietyAdapter);

    ppsCoconutSizeAdapter= ArrayAdapter.createFromResource(this, R.array.coconut_sizes,android.R.layout.simple_spinner_item);
    ppsCoconutSizeAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    ppsFruitsSize.setAdapter(ppsCoconutSizeAdapter);

    ppsProductTypeAdapter= ArrayAdapter.createFromResource(this, R.array.products_type,android.R.layout.simple_spinner_item);
    ppsProductTypeAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    ppsProductType.setAdapter(ppsProductTypeAdapter);

    builder.setTitle("Add Products per Sack");
    builder.setPositiveButton("Submit", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialogInterface, int i) {
            int numberOfTreesValue= Integer.parseInt(ppsNumberOfTree.getText().toString());
            int numberOfFruitsValue= Integer.parseInt(numberOfFruits.getText().toString());
            int numberOfSackValue= Integer.parseInt(numberOfSack.getText().toString());
            int pricePersackValue= Integer.parseInt(priceperSack.getText().toString());

            String choosedVariety= ppsCoconutVariety.getSelectedItem().toString();
            String choosedFruitSize=ppsFruitsSize.getSelectedItem().toString();
            String choosedProductType= ppsProductType.getSelectedItem().toString();
            String dateCreated= getCurrentTimeStamp();
            int initialIncome= numberOfSackValue*pricePersackValue;

            ProductsType productsType= new ProductsType(PRICE_PER_SACK);
            PricePerSack pricePerSack= new PricePerSack(productsType,numberOfTreesValue,numberOfFruitsValue,choosedVariety,choosedFruitSize,choosedProductType,numberOfSackValue,pricePersackValue,initialIncome,dateCreated);
            try {
                pricePerSackIntegerDao= getHelper().getPricePerSackIntegerDao();
                pricePerSackIntegerDao.create(pricePerSack);
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    });

    builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialogInterface, int i) {
            dialogInterface.dismiss();
        }
    });

    AlertDialog alertDialog= builder.create();
    alertDialog.setCanceledOnTouchOutside(false);
    alertDialog.show();
}

这是片段类：

public class Priceperkilo extends Fragment {

final static int PRICE_PER_KILO = 4;
Dao<PricePerKilo,Integer> pricePerKiloIntegerDao;
List<PricePerKilo> pricePerKiloList=null;
DatabaseHelper helper=null;
RecyclerView recyclerView;
PricePerKiloRecyclerViewAdapter pricePerKiloRecyclerViewAdapter= null;


@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
    if (pricePerKiloIntegerDao == null) {
        try {
            pricePerKiloIntegerDao=getHelper().getPricePerKiloIntegerDao();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

       pricePerKiloList= getAllDatas();

    super.onCreate(savedInstanceState);
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View v= inflater.inflate(R.layout.fragment_priceperkilo, container, false);

    pricePerKiloRecyclerViewAdapter= new PricePerKiloRecyclerViewAdapter(pricePerKiloList);
    recyclerView = (RecyclerView)v.findViewById(R.id.priceperkilo_recyclerView);
    recyclerView.setHasFixedSize(true);
    RecyclerView.LayoutManager layoutManager= new LinearLayoutManager(getActivity());
    recyclerView.setLayoutManager(layoutManager);
    recyclerView.setAdapter(pricePerKiloRecyclerViewAdapter);

    pricePerKiloRecyclerViewAdapter.notifyDataSetChanged();

    return v;
}

private DatabaseHelper getHelper() {
    if (helper == null) {
        helper= OpenHelperManager.getHelper(getActivity(),DatabaseHelper.class);
    }
    return helper;
}

// Getting All Datas in database
public List<PricePerKilo> getAllDatas() {

    pricePerKiloList= new ArrayList<>();
    try {
        pricePerKiloList= pricePerKiloIntegerDao.queryForAll();
    } catch (SQLException e) {
        e.printStackTrace();
    }

    return pricePerKiloList;
}

public void updateFragmentRecyclerView() {
    if (pricePerKiloRecyclerViewAdapter != null) {
        pricePerKiloRecyclerViewAdapter.notifyDataSetChanged();
    }
}

}