Question

我有一个像这样的片段

file_list

我有4个片段，所有这些片段都可以通过底栏使用此方法在MainActivity中切换，当用户点击菜单时，它将用另一个片段替换当前片段（默认：Dashboard）：

...

public class Dashboard extends Fragment{
    private RecyclerView mTopSellersListView;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.main_dashboard, container, false);
        mTopSellersListView = (RecyclerView) view.findViewById(R.id.topSellersListView);
        return view;
    }

    public void setTopSellersListView(MyRecycleAdapter adapter){
        mTopSellersListView.setHasFixedSize(true);
        mTopSellersListView.setAdapter(adapter);
        mTopSellersListView.setLayoutManager(new LinearLayoutManager(getActivity()));
        mTopSellersListView.addItemDecoration(new DividerItemDecoration(getActivity(), LinearLayoutManager.VERTICAL));
        mTopSellersListView.setItemAnimator(new DefaultItemAnimator());
    }
}

我访问另一个类（非活动类）中的setTopSellersListView（）

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mDashboardFragment = new Dashboard();
        mOrdersFragment = new Orders();
        mProductsFragment = new Products();
        mSettingFragment = new Setting();
        settingMenu(savedInstanceState);
}

...

public void selectMenu(String menu){
    Fragment fr = null;
    switch (menu) {
        case "Dashboard":
            fr = mDashboardFragment;
            break;
        case "Orders":
            fr = mOrdersFragment;
            break;
        case "Products":
            fr = mProductsFragment;
            break;
        case "Setting":
            fr = mSettingFragment;
            break;
    }
    FragmentManager fm = getFragmentManager();
    FragmentTransaction fragmentTransaction = fm.beginTransaction();
    fragmentTransaction.replace(R.id.fragment, fr);
    fragmentTransaction.addToBackStack(null);
    fragmentTransaction.commit();
}

并在mTopSellersListView.setHasFixedSize（true）获得NullPointerExceptions

Answer 1

首先设置layoutManager而不是使用setHasFizedSize（true）。由于layoutManager确定了recyclerView的大小。

Answer 2

我已经通过在Fragment中的onStart（）中调用setTopSellersListView（）来修复它，它运行良好

无法在Fragment中设置RecycleView Adapter

2 个答案: