Android Retrofit 2：从另一个 Activity 刷新 Recyclerview

Question

所以我有一个应用程序，我在其中使用 Recycler View 显示数据库中的产品列表。每个项目旁边都有删除按钮，工作正常。还有一个扫描项目按钮，它打开一个条形码扫描仪，扫描成功后将新产品添加到数据库并返回到 Recycler 视图显示应该刷新视图并显示新项目。

但我在添加新产品时刷新回收站视图时遇到问题。

还有一个完美运行的删除产品功能，所以我尝试以同样的方式执行添加项目方法，但回收站视图没有刷新。

用户页面activity

    public class UserPage extends AppCompatActivity implements ProductAdaptar.clickedItem {
    Toolbar toolbar;
    RecyclerView recyclerView;
    String rfidNo;
    public static String barcode;
    Button scanItem;
    Button payBill;
    TextView total;
    ProductAdaptar productAdaptar;
    Call<List<UserLoginResp>> productList;
    List<UserLoginResp> productListsItems = new ArrayList<>();


@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_user_page);
        toolbar=findViewById(R.id.toolbar);
        recyclerView=findViewById(R.id.recyclerview);
        scanItem = findViewById(R.id.scanItem);
        payBill = findViewById(R.id.payBill);
        total = findViewById(R.id.total);

        scanItem.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                startActivity(new Intent(getApplicationContext(),ScannerView.class).putExtra("rfid",rfidNo));
            }
        });

        payBill.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                checkout();
            }
        });

        LinearLayoutManager manager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(manager);
        recyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL));
        productAdaptar = new ProductAdaptar(this::clickedItem, this);

        Intent intent =getIntent();
        if(intent.getExtras()!=null){
            rfidNo= intent.getStringExtra("rfid");
        }
        getAllProducts(rfidNo);
        }
        public void getAllProducts(String rfidno){
            LinearLayoutManager manager = new LinearLayoutManager(this);
            recyclerView.setLayoutManager(manager);
            productAdaptar = new ProductAdaptar(this::clickedItem,this);
            productList= ApiClient.getUserPageService().getCartItems(rfidno);
            productList.enqueue(new Callback<List<UserLoginResp>>() {
                @Override
                public void onResponse(Call<List<UserLoginResp>> call, Response<List<UserLoginResp>> response) {
                    if (response.isSuccessful()) {
                        productListsItems = response.body();
                        productAdaptar.setData(productListsItems);
                        RecyclerView recyclerView = findViewById(R.id.recyclerview);
                        recyclerView.setAdapter(productAdaptar);
                        getTotal();
                    }
                }
                @Override
                public void onFailure(Call<List<UserLoginResp>> call, Throwable t) {
                    Log.e("listfailed",t.getLocalizedMessage());
                }
            });
    }

    public void getTotal(){
            Call<getBill> bill = ApiClient.getUserPageService().getBill(rfidNo);
            bill.enqueue(new Callback<getBill>() {
                @Override
                public void onResponse(Call<getBill> call, Response<getBill> response) {
                    if(response.isSuccessful()){
                        getBill getBill = response.body();
                        String bill = String.valueOf(getBill.getBill());
                        total.setText(bill);
                    }
                }

                @Override
                public void onFailure(Call<getBill> call, Throwable t) {
                    Log.e("bill error",""+t);
                }
            });
}

public void checkout(){
    Call<String> payment= APIClientString.getUserPageService().checkout(rfidNo);
    payment.enqueue(new Callback<String>() {
        @Override
        public void onResponse(Call<String> call, Response<String> response) {
            if(response.isSuccessful()){
                getAllProducts(rfidNo);
                Toast.makeText(UserPage.this, "Payment Successful", Toast.LENGTH_SHORT).show();
            }
        }

        @Override
        public void onFailure(Call<String> call, Throwable t) {
                Log.e("paymentfail",""+t);
        }
    });
}


@Override
public void clickedItem(UserLoginResp userLoginResp) {
        Log.e("clicked prodcut", userLoginResp.toString());
}

}

扫描仪视图Class

enter @Override
public void handleResult(Result rawResult) {
    barcode = rawResult.getText();
    if(addItem(barcode,rfidNo)) {
        userPage.getAllProducts(rfidNo);
    }
    onBackPressed();
} 
public boolean addItem(String barcode,String rfidNo){
    final boolean[] res = {false};
    Call<String> resp = APIClientString.getUserPageService().addProduct(barcode,rfidNo);
    resp.enqueue(new Callback<String>() {
        @Override
        public void onResponse(Call<String> call, Response<String> response) {
            if(response.isSuccessful()){
                Toast.makeText(ScannerView.this, response.body().toString(), Toast.LENGTH_SHORT).show();
                res[0] =true;
            }
        }

这是扫描仪 class，它应该从 UserPage Activity 调用 getAllproducts 函数来刷新视图。它没有显示错误，但回收站视图没有更新。

这是适配器Class

public class ProductAdaptar extends RecyclerView.Adapter<ProductAdaptar.ProductAdaptarVH> {

private List<UserLoginResp> productListItems;
private UserPage context;
private clickedItem clickedItem;

public ProductAdaptar(clickedItem clickedItem, UserPage activity) {
    this.clickedItem = clickedItem;
    this.context= activity;
}

public void setData(List<UserLoginResp> productListItems) {
    this.productListItems = productListItems;
    notifyDataSetChanged();
}

@NonNull
@Override
public ProductAdaptarVH onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    return new ProductAdaptar.ProductAdaptarVH(LayoutInflater.
            from(context).inflate(R.layout.row_products,parent,false));
}

@Override
public void onBindViewHolder(@NonNull ProductAdaptarVH holder, int position) {
    UserLoginResp userLoginResp = productListItems.get(position);
    String pName = userLoginResp.getProductName();
    String pQuan = userLoginResp.getQuantity();
    String pPrice = userLoginResp.getProductPrice();
    String pBarcode = userLoginResp.getProductID();
    String userID = userLoginResp.getUserID();
    holder.pName.setText(pName);
    holder.pQuan.setText(pQuan);
    holder.pPrice.setText(pPrice);
    holder.delProdcut.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            delProduct(userID,pBarcode);
        }
    });
    holder.moreDetails.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

        }
    });

}
public interface clickedItem{
    public void clickedItem(UserLoginResp userLoginResp);
}

public void delProduct(String userID, String pBarcode){
    Call<String> res = APIClientString.getUserPageService().deleteProduct(pBarcode,userID);
    res.enqueue(new Callback<String>() {
        @Override
        public void onResponse(Call<String> call, Response<String> response) {
            if(response.isSuccessful()){
                Toast.makeText(context, response.body().toString(), Toast.LENGTH_SHORT).show();
                context.getAllProducts(userID);
            }
        }
        @Override
        public void onFailure(Call<String> call, Throwable t) {
                Log.e("deletefailed",""+t);
        }
    });
}

@Override
public int getItemCount() {
        return productListItems.size();
}

public static class ProductAdaptarVH extends RecyclerView.ViewHolder {

    TextView pName;
    TextView pQuan;
    TextView pPrice;
    Button delProdcut;
    Button moreDetails;

    public ProductAdaptarVH(@NonNull View itemView) {
        super(itemView);
         pName=itemView.findViewById(R.id.pName);
         pQuan=itemView.findViewById(R.id.pQuantity);
         pPrice=itemView.findViewById(R.id.pPrice);
         delProdcut=itemView.findViewById(R.id.delProduct);
         moreDetails=itemView.findViewById(R.id.moreDetails);
    }
}

}

在这个产品适配器中有一个删除产品项目的功能

holder.delProdcut.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            delProduct(userID,pBarcode);
        }
    });
    public void delProduct(String userID, String pBarcode){
    Call<String> res = APIClientString.getUserPageService().deleteProduct(pBarcode,userID);
    res.enqueue(new Callback<String>() {
        @Override
        public void onResponse(Call<String> call, Response<String> response) {
            if(response.isSuccessful()){
                Toast.makeText(context, response.body().toString(), Toast.LENGTH_SHORT).show();
                context.getAllProducts(userID);
            }
        }
        @Override
        public void onFailure(Call<String> call, Throwable t) {
                Log.e("deletefailed",""+t);
        }
    });
}

它还从 UserPage activity 调用 getProduts 函数，它工作得很好，但 AddItem 函数不刷新视图。

Retrofit API 也完全正常工作，问题仅在于刷新 Item Add 上的回收视图显示。

我是 android 编码的新手，所以我似乎不明白该怎么做。

Answer 1

当您使用 getAllProducts() 方法刷新适配器时，它在 onCreate() 中被调用。现在，无论何时启动 ScannerView activity，UserPage activity 都会暂停，然后在 ScannerView activity 完成时启动（未创建）。因此，您应该在 onStart() 方法中调用 getAllProducts()，如下所示：

    @Override
    protected void onStart() {
        super.onStart();

        Intent intent = getIntent();
        if (intent.getExtras() != null) {
            rfidNo = intent.getStringExtra("rfid");
        }

        getAllProducts(rfidNo);
    }

Android Retrofit 2：从另一个 Activity 刷新 Recyclerview

Andriod Retrofit 2: Refreshing Recycler View From from another Activity

android

android-studio

android-recyclerview

retrofit2