viewpager2+tablayout+recyclerview+fragment实现页面的切换

这个实现需要以下步骤：

1. 在布局文件中添加ViewPager2和TabLayout：

<com.google.android.material.tabs.TabLayout
    android:id="@+id/tab_layout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:tabGravity="fill"
    app:tabMode="fixed" />

<androidx.viewpager2.widget.ViewPager2
    android:id="@+id/view_pager"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

2. 在代码中初始化ViewPager2和TabLayout：

ViewPager2 viewPager = findViewById(R.id.view_pager);
TabLayout tabLayout = findViewById(R.id.tab_layout);

viewPager.setAdapter(new MyPagerAdapter(this));
new TabLayoutMediator(tabLayout, viewPager,
        (tab, position) -> tab.setText("Tab " + (position + 1))
).attach();

3. 创建PagerAdapter，用于管理Fragment：

public class MyPagerAdapter extends FragmentStateAdapter {

    public MyPagerAdapter(FragmentActivity fa) {
        super(fa);
    }

    @Override
    public Fragment createFragment(int position) {
        return new MyFragment(position + 1);
    }

    @Override
    public int getItemCount() {
        return 3;
    }
}

4. 创建Fragment，用于显示RecyclerView：

public class MyFragment extends Fragment {

    private int mTabNumber;

    public MyFragment(int tabNumber) {
        mTabNumber = tabNumber;
    }

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

        RecyclerView recyclerView = rootView.findViewById(R.id.recycler_view);
        recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
        recyclerView.setAdapter(new MyRecyclerViewAdapter(mTabNumber));

        return rootView;
    }
}

5. 创建RecyclerViewAdapter，用于显示数据：

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

    private int mTabNumber;

    public MyRecyclerViewAdapter(int tabNumber) {
        mTabNumber = tabNumber;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.item_my, parent, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        holder.mTextView.setText("Tab " + mTabNumber + ", Item " + (position + 1));
    }

    @Override
    public int getItemCount() {
        return 10;
    }

    public static class ViewHolder extends RecyclerView.ViewHolder {

        public TextView mTextView;

        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            mTextView = itemView.findViewById(R.id.text_view);
        }
    }
}

6. 创建RecyclerView的item布局文件和Fragment的布局文件：

item_my.xml：

<TextView
    android:id="@+id/text_view"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:padding="16dp" />

fragment_my.xml：

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

这样就完成了实现。每个Tab都显示一个RecyclerView，切换Tab时切换RecyclerView。