片段方向管理

Question

Fragment 保留状态让我感到不舒服。我不知道我在哪里犯了错误。请帮帮我。

public class FragmentNotification extends Fragment implements OnAruguments {

    public static final String LIST_ITEMS = "list_items";
    public static final String TEMP_ITEMS = "temp_items";

    List<DBNotifications> notificationModels = new ArrayList<>();
    List<DBNotifications> tempModelList = new ArrayList<>();
    NotificationAdapter notificationAdapter;

    void setAdapter() {
        if (notificationAdapter == null) {
            notificationAdapter = new NotificationAdapter(getActivity(),     tempModelList);
          listView.setAdapter(notificationAdapter);
        } else {
            notificationAdapter.notifyDataSetChanged();
        }
        if (tempModelList.size() > 0) {
            listView.setVisibility(View.VISIBLE);
            cstmTxtNoItems.setVisibility(View.GONE);
        } else {
            listView.setVisibility(View.GONE);
            cstmTxtNoItems.setVisibility(View.VISIBLE);
        }
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        if (savedInstanceState != null) {
            notificationModels = savedInstanceState.getParcelableArrayList(LIST_ITEMS);
            tempModelList = savedInstanceState.getParcelableArrayList(TEMP_ITEMS);
        }
    }

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setRetainInstance(true);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        view = inflater.inflate(R.layout.notification, container, false);
        init();
        createItemsList();

        return view;
    }

    void init() {
        listview= (ListView) view.findViewById(R.id.listView);
    }

    void createItemsList() {
        new NotificationModelCreation().execute();
    }

    void createNotificationModelList() {
        String query = "SELECT * FROM notifications WHERE id='" + tempModel.getId() + "' AND code='" + Constants.CODE + "' ORDER BY priority DESC ";
        List<Notifications> notificationsList = Notifications.findWithQuery(Notifications.class, query);
        if (notificationsList != null && notificationsList .size() > 0) {
            notificationModels.addAll(notificationsList );
            tempModelList.addAll(notificationsList );
        }
    }

    @Override
    public void onResume() {
        super.onResume();

        setAdapter();// I have tried to set adapter onResume. Because, onCreateview will not be called on setRetainInstance =true
    }

    @Override
    public void setOnArguments(Bundle bundle) {}

    class NotificationModelCreation extends AsyncTask<Void, Void, Void> {
        @Override
        protected Void doInBackground(Void... params) {
            createNotificationModelList();
            return null;
        }

        @Override
        protected void onPostExecute(Void aVoid) {
            super.onPostExecute(aVoid);
            setAdapter();
        }
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putParcelableArrayList(LIST_ITEMS, (ArrayList<? extends Parcelable>) notificationModels);
        outState.putParcelableArrayList(TEMP_ITEMS, (ArrayList<? extends Parcelable>) tempModelList);

    }
}

第一次加载时，它运行良好。但是当配置改变时，Adapter 被设置，但是没有视图显示。 ListView 也已初始化。因为，我得到了Fragment 这样的标签。

getSupportManager().findFragmentByTag("tag");

得到Fragment后，我使用了以下代码。

FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.setCustomAnimations(R.anim.enter_from_right,
        R.anim.exit_to_left,
        R.anim.enter_from_right,
        R.anim.exit_to_left)
        .add(R.id.fragment_container, fragment, tag)
        .addToBackStack(fragment.getClass().getName())
        .commit();

我也管理过后台堆栈。那里没有问题。唯一的问题是视图不可见。即使列表中有项目并且ListView 也与适配器一起完美初始化。

已编辑：

我删除了 notifyDataSetChanged()。我每次都设置适配器。现在它工作正常。

Answer 1

将此行放在您加载此片段的 Manifest 的 Activity 标记中

android:configChanges="keyboardHidden|orientation"

它不会影响任何数据，但方向会发生变化

编码愉快！！