Android Fragment 类变量在 onOptionsItemSelected() 方法中不可用

Question

我在 Activity 中有一个片段，如下所示，

   public class ViewRecordFragment extends Fragment {

    private Integer recordId;

    public ViewRecordFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        if (recordId != null) {
            new ViewRecordActivity.GetRecordToDisplay(getActivity()).execute(recordId);
            loadImageResourcesAsync(recordId);
        }

        return inflater.inflate(R.layout.fragment_view_record, container, false);
    }

    public static ViewRecordFragment newInstance(Integer recordId) {
        ViewRecordFragment fragment = new ViewRecordFragment();
        Bundle bundle = new Bundle();
        bundle.putInt(BundleHelper.RECORD_ID, recordId);
        fragment.setArguments(bundle);
        fragment.setRetainInstance(true);
        return fragment;
    }

    private void loadImageResourcesAsync(Integer recordId) {
        new LoadImageResourcesAsync(getActivity()).execute(recordId);
    }


    @Override
    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setHasOptionsMenu(true);

        if (getArguments() != null) {
            recordId = getArguments().getInt(BundleHelper.RECORD_ID);
        }
    }

    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        menu.clear();
        inflater.inflate(R.menu.menu_view_record, menu);
        //super.onCreateOptionsMenu(menu, inflater);
    }


    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // handle item selection
        switch (item.getItemId()) {
            case R.id.action_new_photo:

                //Integer recordId = getArguments().getInt(BundleHelper.RECORD_ID);

                Intent intent = new Intent(getActivity(), CameraActivity.class);
                intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                Bundle bundle = new Bundle();
                bundle.putInt(BundleHelper.RECORD_ID, recordId);
                bundle.putString(BundleHelper.UNIQUE_IDENTIFIER, UUID.randomUUID().toString());
                intent.putExtras(bundle);
                getActivity().startActivity(intent);
                return true;

            default:
                return super.onOptionsItemSelected(item);
        }
    }
}

并且活动使用这个片段来显示单个记录，

public class ViewRecordActivity extends AppCompatActivity {

    private Toolbar toolbar = null;
    private Integer recordId;
    private String patientNo;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_view_record);


        toolbar = (Toolbar) findViewById(R.id.header);
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getSupportActionBar().setTitle("Record");

        Bundle extras = getIntent().getExtras();
        if (extras != null) {
            recordId = extras.getInt(BundleHelper.RECORD_ID);
            patientNo = extras.getString(BundleHelper.PATIENT_NO);
            getSupportActionBar().setSubtitle("Patient Id: " + patientNo);
        }

        if (savedInstanceState == null) {
            ViewRecordFragment viewRecordFragment = ViewRecordFragment.newInstance(recordId);
            FragmentManager fragmentManager = getSupportFragmentManager();
            fragmentManager
                    .beginTransaction()
                    .replace(R.id.view_record_fragment, viewRecordFragment
                    ).commit();
        }
    }


    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case android.R.id.home:
                this.finish();
                return true;
            default:
                return super.onOptionsItemSelected(item);
        }
    }

    public static class GetRecordToDisplay extends GetRecordAsync {

        private TextView dos;
        private TextView facultyName;
        private TextView patientName;
        private TextView patientId;

        public GetRecordToDisplay(Activity activity) {
            super(activity);
            this.dos = (TextView) activity.findViewById(R.id.date_submitted_text);
            this.facultyName = (TextView) activity.findViewById(R.id.name_text);
            this.patientName = (TextView) activity.findViewById(R.id.customer_name_text);
            this.patientId = (TextView) activity.findViewById(R.id.customer_id_text);
        }


        @Override
        protected void onPostExecute(Customer customer) {

            if (customer != null) {
                this.dos.setText(customer.getDOS_D());
                this.facultyName.setText(customer.getDOS_R());
                this.patientName.setText(customer.getCUSTOMER_N());
                this.patientId.setText(customer.getCUSTOMER_C());
            }
        }

    }

当我尝试通过单击菜单项来启动新活动时，就会出现问题。单击菜单项时，我传递的这个recordId 为空。

我不确定我在这里缺少什么。我可以看到 recordId 在 Activity 内创建片段时被分配（在调试模式下）。

但是当我单击菜单项并进入该特定菜单项案例时，recordId 为空。但我期待在创建片段时分配给它的 recordId。

Answer 1

您正在为您的片段设置参数，但您没有使用它们。在片段的 onCreate 方法中执行此操作：

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setHasOptionsMenu(true);
    recordId = getArguments().getInt(BundleHelper.RECORD_ID);
}