android studio ：有一个页面，左侧有四个RecyclerView页面的button按钮，右侧是4个不同的fragment页面，要求：写一个RecyclerViewadapter，使按不同的button按钮，右侧显示不同的fragment页面

好的，这是一个比较典型的RecyclerView+Fragment的组合使用场景。

首先，你需要在Activity中定义四个Button和一个FrameLayout用于承载Fragment，代码类似于：

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private RecyclerView recyclerView;
    private Button btn1;
    private Button btn2;
    private Button btn3;
    private Button btn4;
    private FrameLayout container;
    private Fragment1 fragment1;
    private Fragment2 fragment2;
    private Fragment3 fragment3;
    private Fragment4 fragment4;
    private RecyclerViewAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // 初始化控件
        recyclerView = findViewById(R.id.recycler_view);
        btn1 = findViewById(R.id.btn1);
        btn2 = findViewById(R.id.btn2);
        btn3 = findViewById(R.id.btn3);
        btn4 = findViewById(R.id.btn4);
        container = findViewById(R.id.container);

        // 设置按钮点击事件
        btn1.setOnClickListener(this);
        btn2.setOnClickListener(this);
        btn3.setOnClickListener(this);
        btn4.setOnClickListener(this);

        // 初始化Fragment
        fragment1 = new Fragment1();
        fragment2 = new Fragment2();
        fragment3 = new Fragment3();
        fragment4 = new Fragment4();

        // 设置默认显示的Fragment
        getSupportFragmentManager().beginTransaction().replace(R.id.container, fragment1).commit();

        // 初始化RecyclerView
        adapter = new RecyclerViewAdapter(this);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        recyclerView.setAdapter(adapter);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.btn1:
                // 切换到Fragment1
                getSupportFragmentManager().beginTransaction().replace(R.id.container, fragment1).commit();
                break;
            case R.id.btn2:
                // 切换到Fragment2
                getSupportFragmentManager().beginTransaction().replace(R.id.container, fragment2).commit();
                break;
            case R.id.btn3:
                // 切换到Fragment3
                getSupportFragmentManager().beginTransaction().replace(R.id.container, fragment3).commit();
                break;
            case R.id.btn4:
                // 切换到Fragment4
                getSupportFragmentManager().beginTransaction().replace(R.id.container, fragment4).commit();
                break;
            default:
                break;
        }
    }
}

接着，你需要编写RecyclerViewAdapter，代码类似于：

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> {
    private Context context;

    public RecyclerViewAdapter(Context context) {
        this.context = context;
    }

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

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        holder.btn.setText("按钮" + (position + 1));
    }

    @Override
    public int getItemCount() {
        return 4;
    }

    public static class ViewHolder extends RecyclerView.ViewHolder {
        private Button btn;

        public ViewHolder(View itemView) {
            super(itemView);
            btn = itemView.findViewById(R.id.btn);
        }
    }
}

最后，你需要在每个Fragment中实现相应的布局和逻辑即可。这里给出Fragment1的代码示例：

public class Fragment1 extends Fragment {
    private TextView tvTitle;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment1, container, false);
        tvTitle = view.findViewById(R.id.tv_title);
        return view;
    }

    @Override
    public void onResume() {
        super.onResume();
        tvTitle.setText("Fragment1");
    }
}

其中，fragment1.xml布局文件中只需要包含一个TextView即可。

这样，当你点击左侧的RecyclerView中的按钮时，右侧会显示相应的Fragment页面。