Question

我有一个名为rootActivity的活动，其中我有一个rootContainer，我在其中替换片段。

现在，我替换的第一个片段是DashboardFragment。

我现在点击十字架打开一个像这样的新片段...... 现在，当我按下后退按钮时，仪表板片段的内容将丢失。

有人可以帮助我

这是一段视频，展示了真正发生的事情。 https://youtu.be/NobqYUCEZKY

DashboardFragment 的代码（包含标签内的片段）

public class DashboardFragment extends Fragment {
    private Toolbar toolbar;
    private TabLayout tabLayout;
    private ViewPager viewPager;
    private View rootView;

    /**
     *
     * @param config : For setting up stuff by the given config
     * @return
     */
    public static DashboardFragment newInstance(Bundle config) {

        DashboardFragment fragment = new DashboardFragment();
        fragment.setArguments(config);
        return fragment;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        rootView = inflater.inflate(R.layout.activity_dashboard, container, false);
        toolbar = (Toolbar) rootView.findViewById(R.id.toolbar);
        ((RootActivity)getActivity()).setSupportActionBar(toolbar);

        viewPager = (ViewPager) rootView.findViewById(R.id.viewpager);
        setupViewPager(viewPager);

        tabLayout = (TabLayout) rootView.findViewById(R.id.tabs);
        tabLayout.setupWithViewPager(viewPager);
        setupTabIcons();

        return rootView;
    }

    private void setupTabIcons() {
        tabLayout.getTabAt(0).setIcon(android.R.drawable.btn_star_big_off);
        tabLayout.getTabAt(1).setIcon(android.R.drawable.btn_star_big_on);
    }

    private void setupViewPager(ViewPager viewPager) {
        ViewPagerAdapter adapter = new ViewPagerAdapter(getActivity().getSupportFragmentManager());
        adapter.addFragment(new TrackeesFragment(), "Trackee");
        adapter.addFragment(new TrackersFragment(), "Trackers");
        viewPager.setAdapter(adapter);
    }

    class ViewPagerAdapter extends FragmentStatePagerAdapter {
        private final List<Fragment> mFragmentList = new ArrayList<>();
        private final List<String> mFragmentTitleList = new ArrayList<>();

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

        @Override
        public Fragment getItem(int position) {
            return mFragmentList.get(position);
        }

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

        public void addFragment(Fragment fragment, String title) {
            mFragmentList.add(fragment);
            mFragmentTitleList.add(title);
        }

        @Override
        public Object instantiateItem(ViewGroup container, int position) {
            return super.instantiateItem(container, position);
        }

        @Override
        public CharSequence getPageTitle(int position) {
            return null;
        }
    }
}

Answer 1

尝试更改

中的以下行

setupViewPager(ViewPager viewPager) {}

更改

ViewPagerAdapter adapter = new ViewPagerAdapter(getActivity().getSupportFragmentManager());

要

ViewPagerAdapter adapter = new ViewPagerAdapter(getChildFragmentManager());

返回选项卡片段时，视图不会膨胀

1 个答案: