要向ViewPager添加按钮，可以使用LayoutInflater在每个页面的布局中添加一个按钮。以下是一个示例：

1. 编写布局文件activity_main.xml：

2. 编写布局文件fragment_page.xml：

3. 编写适配器类MyPagerAdapter.java：

public class MyPagerAdapter extends FragmentPagerAdapter {

public MyPagerAdapter(FragmentManager fm) {
    super(fm);
}

@Override
public Fragment getItem(int position) {
    return PageFragment.newInstance(position);
}

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

}

4. 编写Fragment类PageFragment.java：

public class PageFragment extends Fragment {

private static final String ARG_PAGE = "ARG_PAGE";
private int mPage;

public static PageFragment newInstance(int page) {
    Bundle args = new Bundle();
    args.putInt(ARG_PAGE, page);
    PageFragment fragment = new PageFragment();
    fragment.setArguments(args);
    return fragment;
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mPage = getArguments().getInt(ARG_PAGE);
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_page, container, false);
    Button button = (Button) view.findViewById(R.id.button);
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            // 按钮点击事件处理
        }
    });
    return view;
}

}

5. 在MainActivity.java中设置ViewPager和适配器：

public class MainActivity extends AppCompatActivity {

private ViewPager viewPager;

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

    viewPager = (ViewPager) findViewById(R.id.viewPager);
    viewPager.setAdapter(new MyPagerAdapter(getSupportFragmentManager()));
}

}