Question

我尝试查看具有动态内部活动（来自服务器的数据）的布局。

已成功检索到服务器中的数据。

内部活动：

onCreate：

setupTab();
loadBarang();

setupTab：

private void setupTab(){
        adapterViewPagerBarangOrder = new AdapterViewPagerBarangOrder(getSupportFragmentManager());
        viewPager.setAdapter(adapterViewPagerBarangOrder);
        tabLayout.setupWithViewPager(viewPager);
    }

请求服务器

private void loadBarang(){
...
// success
adapterViewPagerBarangOrder.setGroupBarangs(listGroupBarang);
...
}

AdapterViewPager：

public class AdapterViewPagerBarangOrder extends FragmentStatePagerAdapter {

    List<CreateOrderFragment> fragments;
    List<GroupBarang> groupBarangs;

    public AdapterViewPagerBarangOrder(@NonNull FragmentManager fm) {
        super(fm, BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT);
        this.fragments = new ArrayList<>();
        this.groupBarangs = new ArrayList<>();
    }

    public void setGroupBarangs(List<GroupBarang> groupBarangs) {
        this.groupBarangs = groupBarangs;
        for (GroupBarang groupBarang: groupBarangs) {
            fragments.add(CreateOrderFragment.newInstance(groupBarang.getListBarang()));
        }
        notifyDataSetChanged();
    }

    @NonNull
    @Override
    public Fragment getItem(int position) {
        return fragments.size()>0? fragments.get(position) : null;
    }

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

    @Nullable
    @Override
    public CharSequence getPageTitle(int position) {
        return groupBarangs.size()>0? groupBarangs.get(position).getGroupName() : null;
    }
}

片段

public class CreateOrderFragment extends BaseFragment {
    private static final String ARG_LIST_BARANG = "create_order_arg_list_barang";
    private AdapterBarangOrder adapterBarangOrder;
    private List<Barang> listBarang;
    private EmptyRecyclerView mRecyclerView;
    private CartManager cartManager;

    public CreateOrderFragment() {
        listBarang = new ArrayList<>();
    }

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            listBarang = (List<Barang>) getArguments().getSerializable("ARG_LIST_BARANG");
        }
// HERE CHECK listBarang ALWAYS NULL
// ANY HELP?

    }

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        view = inflater.inflate(R.layout.fragment_create_order, container, false);
        cartManager = new CartManager(getContext());

        adapterBarangOrder = new AdapterBarangOrder(getContext());
        mRecyclerView = view.findViewById(R.id.create_order_recycler_view);
        mRecyclerView.setLayoutManager(new LinearLayoutManager(getContext(), RecyclerView.VERTICAL, false));
        mRecyclerView.setAdapter(adapterBarangOrder);
        adapterBarangOrder.setListBarang(listBarang);
        return view;
    }

    public static CreateOrderFragment newInstance(List<Barang> listBarang){
        CreateOrderFragment fragment = new CreateOrderFragment();
        Bundle args = new Bundle();
        args.putSerializable(ARG_LIST_BARANG, (Serializable) listBarang);

// HERE CHECK listBarang NOT NULL and NOT EMPTY

        fragment.setArguments(args);
        return fragment;
    }

}

检查fragment.newInstance内部的listBarang的大小不为null且不为空

但要检查fragment.oncreate参数内部始终为空

Answer 1

替换

listBarang = (List<Barang>) getArguments().getSerializable("ARG_LIST_BARANG");

与

listBarang = (List<Barang>) getArguments().getSerializable(ARG_LIST_BARANG);

设置和获取参数时，键应相同。

Answer 2

您正在使用

getSerializable("ARG_LIST_BARANG")

但是通过使用

putSerializable(ARG_LIST_BARANG, (Serializable) listBarang);

在ARG_LIST_BARANG的值为"create_order_arg_list_barang"的情况下-您没有在两侧使用相同的键。您应该删除getSerializable中的引号以实际使用您的变量：

listBarang = (List<Barang>) getArguments().getSerializable(ARG_LIST_BARANG);

片段内的getArguments（）始终为null

2 个答案: