java - 如何在 Android Studio 3.5 - 最新版本中将选项卡式 Activity 添加到抽屉导航片段中

Question

请问如何在 Android Studio 3.5 - 最新版本中将选项卡式 Activity 添加到抽屉导航片段中。我遇到“无法通过 findViewById 和 getSupportFragmentManager 解析方法”的问题。有什么我需要导入的吗，我正在使用最新版本和 androidx.如果我向类中添加实现 FragmentActivity 或任何其他 Activity ，它将引发关闭应用程序的异常。

公共(public)类 SendMoneyFragment 扩展 Fragment {

private SendMoneyViewModel toolsViewModel;

public View onCreateView(@NonNull LayoutInflater inflater,
                         ViewGroup container, Bundle savedInstanceState) {
    toolsViewModel =
            ViewModelProviders.of(this).get(SendMoneyViewModel.class);
    View  root = inflater.inflate(R.layout.fragment_sendmoney, container, false);
    final TextView textView = root.findViewById(R.id.text_sendmoney);
    toolsViewModel.getText().observe(this, new Observer<String>() {
        @Override
        public void onChanged(@Nullable String s) {
            textView.setText(s);
        }
    });
    return root;

    //setupViewPager();

    //method two
    ViewPager viewPager = (ViewPager) findViewById(R.id.pager);
    TabsAdapter adapter = new TabsAdapter(getSupportFragmentManager());
    viewPager.setAdapter(adapter);

    TabLayout tabLayout = (TabLayout) findViewById(R.id.main_tabs);
    tabLayout.setupWithViewPager(viewPager);
}

Answer 1

该解决方案完美运行:

公共(public)类 SendMoneyFragment 扩展 Fragment {

ViewPager pager;


      private SendMoneyViewModel toolsViewModel;

  public View onCreateView(@NonNull LayoutInflater inflater,
                         ViewGroup container, Bundle savedInstanceState) {
      toolsViewModel = ViewModelProviders.of(this).get(SendMoneyViewModel.class);
      View root = inflater.inflate(R.layout.fragment_sendmoney, container, false);
      final TextView textView = root.findViewById(R.id.text_sendmoney);

      TabLayout tabs = (TabLayout) root.findViewById(R.id.main_tabs);

      pager=(ViewPager) root.findViewById(R.id.pager);

      ViewPagerAdapter adapter = new ViewPagerAdapter(getFragmentManager());

      adapter.addFragment(new MoneyAccount(), "Send To Accounts");
      adapter.addFragment(new MoneyAgents(), "Send To Agents");
      adapter.addFragment(new MoneyBanks(), "Send To Banks");

      pager.setAdapter(adapter);
      tabs.setupWithViewPager(pager);

      toolsViewModel.getText().observe(this, new Observer<String>() {
        @Override
        public void onChanged(@Nullable String s) {
            textView.setText(s);
        }
    });
    return root;



}



class ViewPagerAdapter extends FragmentPagerAdapter {
    private final List<Fragment> mList = new ArrayList<>();
    private final List<String> mTitleList = new ArrayList<>();

    public ViewPagerAdapter(FragmentManager supportFragmentManager) {
        super(supportFragmentManager);
    }

    @Override
    public Fragment getItem(int i) {
        return mList.get(i);
    }

    @Override
    public int getCount() {
        return mList.size();
    }

    public void addFragment(Fragment fragment, String title) {
        mList.add(fragment);
        mTitleList.add(title);
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return mTitleList.get(position);
    }
}