问回收器视图:尝试在空对象引用上调用虚拟方法

EN

Attempt to invoke virtual method 'void androidx.recyclerview.widget.RecyclerView.setAdapter(androidx.recyclerview.widget.RecyclerView$Adapter)' on a null object reference

package com.sti.lazshop;

import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.os.Bundle;

import com.sti.lazshop.databinding.ActivityMainBinding;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    ActivityMainBinding binding;
    ArrayList<ItemModel> itemModels = new ArrayList<>();
    int[] itemImages = {R.drawable.item_huion, R.drawable.item_iphone};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding = ActivityMainBinding.inflate(getLayoutInflater());
        setContentView(binding.getRoot());
        RecyclerView recyclerView = findViewById(R.id.mRecyclerView);
        Item_RecyclerViewAdapter adapter = new Item_RecyclerViewAdapter(this, itemModels);
        setItemModels();
        recyclerView.setAdapter(adapter);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        replaceFragment(new HomeFragment());

        binding.bottomNavigationView2.setOnItemSelectedListener(item -> {

            switch (item.getItemId()) {
                case R.id.home:
                    replaceFragment(new HomeFragment());
                    break;
                case R.id.cart:
                    replaceFragment(new CartFragment());
                    break;
                case R.id.account:
                    replaceFragment(new AccountFragment());
                    break;

            }
            return true;
        });

    }

    private void replaceFragment(Fragment fragment) {
        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.replace(R.id.frameLayout, fragment);
        fragmentTransaction.commit();

    }

    private void setItemModels() {
        String[] itemNames = getResources().getStringArray(R.array.item_full_txt);
        String[] itemPrices = getResources().getStringArray(R.array.item_prices);

        for (int i = 0; i < itemNames.length; i++) {
            itemModels.add(new ItemModel(
                    itemNames[i],
                    itemPrices[i],
                    itemImages[i]));
        }

    }

}

package com.sti.lazshop;

import android.os.Bundle;

import androidx.fragment.app.Fragment;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class HomeFragment extends Fragment {

    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    private String mParam1;
    private String mParam2;

    public HomeFragment() {
    }

    public static HomeFragment newInstance(String param1, String param2) {
        HomeFragment fragment = new HomeFragment();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

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

        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        return inflater.inflate(R.layout.fragment_home, container, false);
    }
}

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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"
    tools:context=".HomeFragment">

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/mRecyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</FrameLayout>