android - @override 在我的电子商务应用程序中的 android studio 活动中在 android studio 中给出错误，该应用程序来自 github demol

Question

我有一个购物车片段，我将它转换为一个活动，现在它给出了这些错误。

错误：

1.Method 不会覆盖其超类中的方法（第 86 行）

2.无法解析方法'onCreate(android.view.LayoutInflater, android.view.ViewGroup, android.os.Bundle)'（第88行）

CartActivity.java

    package com.example.shoppingcart;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;

import android.content.Intent;
import android.os.Bundle;



import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import android.view.View;
import androidx.lifecycle.Observer;
import androidx.lifecycle.ViewModelProvider;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.recyclerview.widget.DividerItemDecoration;
import androidx.recyclerview.widget.RecyclerView;

import android.provider.DocumentsContract;
import android.text.TextUtils;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.RadioButton;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.Toolbar;

import com.example.shoppingcart.R;
import com.example.shoppingcart.adapters.CartListAdapter;
import com.example.shoppingcart.cartholder;
import com.example.shoppingcart.databinding.FragmentCartBinding;
import com.example.shoppingcart.dataholder;
import com.example.shoppingcart.models.CartItem;
import com.example.shoppingcart.productholder;
import com.example.shoppingcart.viewmodels.ShopViewModel;
import com.example.shoppingcart.views.CartFragment;
import com.example.shoppingcart.views.CheckoutActivity;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.firestore.DocumentSnapshot;
import com.google.firebase.firestore.FirebaseFirestore;
import com.google.firebase.firestore.QuerySnapshot;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.HashMap;
import java.util.List;
import java.util.UUID;
import java.util.zip.Inflater;

import static androidx.core.content.ContentProviderCompat.requireContext;

public class CartActivity extends AppCompatActivity implements CartListAdapter.CartInterface {

    private static final String TAG = "CartActivity";
    private ImageView productImage;
    private TextView productname;
    private TextView productprice;
    private TextView productcategory;
    private Spinner productquantity;
    View view;
    UUID uuid = UUID.randomUUID();
    String randomUUID = uuid.toString().trim();
    ShopViewModel shopViewModel;
    FragmentCartBinding fragmentCartBinding;
    NavController navController;
    Button button;
    private FirebaseAuth auth;
    private FirebaseFirestore firestore;


    @Override
    protected void onCreate(LayoutInflater inflater,ViewGroup container, Bundle savedInstanceState ) {
        super.onCreate(inflater,container,savedInstanceState);
        fragmentCartBinding = FragmentCartBinding.inflate(inflater, container, false);
        setContentView(fragmentCartBinding.getRoot());

        auth=FirebaseAuth.getInstance();
        firestore=FirebaseFirestore.getInstance();


        firestore.collection("Get to cart").document(randomUUID).collection("User").get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
            @Override
            public void onComplete(@NonNull Task<QuerySnapshot> task) {
                if(task.isSuccessful()){
                    for (DocumentSnapshot doc : task.getResult().getDocuments()){
                        CartItem myCartModel=doc.toObject(CartItem.class);
                    }
                }
            }
        });

        navController = Navigation.findNavController(view);

        final CartListAdapter cartListAdapter = new CartListAdapter(this);
        fragmentCartBinding.cartRecyclerView.setAdapter(cartListAdapter);

        shopViewModel = new ViewModelProvider(this).get(ShopViewModel.class);
        shopViewModel.getCart().observe(this, new Observer<List<CartItem>>() {
            @Override
            public void onChanged(List<CartItem> cartItems) {
                cartListAdapter.submitList(cartItems);
                fragmentCartBinding.placeOrderButton.setEnabled(cartItems.size() > 0);
            }
        });

        shopViewModel.getTotalPrice().observe(this, new Observer<Double>() {
            @Override
            public void onChanged(Double aDouble) {
                fragmentCartBinding.orderTotalTextView.setText("Total: PKR " + aDouble.toString());


            }
        });

        button = (Button) findViewById(R.id.placeOrderButton);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(CartActivity.this, CheckoutActivity.class);
                intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
                startActivity(intent);
                finishActivity();
            }
        });
    }


    private void finishActivity() {
        if (CartActivity.this != null) {
            CartActivity.this.finish();
        }
    }
    





    public void deleteItem(CartItem cartItem) {
        shopViewModel.removeItemFromCart(cartItem);
    }

    public void changeQuantity(CartItem cartItem, int quantity) {
        shopViewModel.changeQuantity(cartItem, quantity);
    }

}

activity_cart.xml

    <?xml version="1.0" encoding="utf-8"?>
    <ScrollView 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">
    
        <LinearLayout
            android:orientation="vertical"
            tools:context=".views.CartFragment"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">
    
            <androidx.recyclerview.widget.RecyclerView
                android:id="@+id/cartRecyclerView"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
                tools:listitem="@layout/cart_row"
                tools:itemCount="2"
                />
    
            <Space
                android:layout_width="match_parent"
                android:layout_height="16dp" />
    
            <TextView
                android:id="@+id/orderTotalTextView"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="end"
                android:layout_margin="8dp"
                android:text="Total: PKR 26"
                android:textAppearance="@style/TextAppearance.MaterialComponents.Headline6" />
    
            <Button
                android:id="@+id/placeOrderButton"
                style="@style/Widget.MaterialComponents.Button.UnelevatedButton"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_gravity="end"
                android:layout_margin="8dp"
                android:text="Proceed To Checkout"
                android:textAppearance="@style/TextAppearance.MaterialComponents.Caption" />
    
        </LinearLayout>
</ScrollView>

标签： androidandroid-activityoperator-overloading

Answer 1

您应该将 onCreate 方法更改为 Activity 的正常变体

    @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);