超級(jí)難解釋。這是我在報(bào)告中遇到的錯(cuò)誤：Attempt to invoke virtual method 'java.lang.Object android.content.Context.getSystemService(java.lang.String)' on a null object reference當(dāng)您進(jìn)出片段時(shí)，這似乎是間歇性發(fā)生的。該錯(cuò)誤似乎發(fā)生在適配器中。這是所謂的地方：    @Nullable    @Override    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {        getActivity().setTitle("Shipments");        myView = inflater.inflate(R.layout.shipments_out_layout, container, false);        listView = myView.findViewById(R.id.listView);        fetchShipments();        return myView;    }    /**     * Fetch shipments     */    public void fetchShipments()    {        shipmentsService.fetchFromServer(getActivity());    }    /**     * Show shipments     */    public void showShipments(){        RealmResults<Shipment> savedShipments = shipmentsService.all();        ShipmentsAdaptor adaptor = new ShipmentsAdaptor(savedShipments, this.getContext());        listView.setAdapter(adaptor);    }這是適配器出現(xiàn)錯(cuò)誤的地方：public class ShipmentsAdaptor extends ArrayAdapter<Shipment> {private RealmResults<Shipment> dataSet;Context mContext;// View lookup cacheprivate static class ViewHolder {    TextView stockItemId;    TextView technicianName;    TextView shipmentDate;}public ShipmentsAdaptor(RealmResults<Shipment> data, Context context){    super(context, R.layout.shipments_out_row_item, data);    this.dataSet = data;    this.mContext = context;}具體來說就是這行： super(context, R.layout.shipments_out_row_item, data);我認(rèn)為這可能與我們將上下文插入適配器，然后在完成頁面之前更改頁面的方式有關(guān)，但事實(shí)證明這沒有定論。