1
Fragment保留狀態令我感到不舒服。我不知道我犯了什麼錯誤。請幫助我們。片段定位管理
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);
}
}
當它第一次加載時，它運行良好。但是當配置改變時，設置了Adapter，但沒有顯示視圖。 ListView也已初始化。因爲，我通過這樣的標籤獲得Fragment。
getSupportManager().findFragmentByTag("tag");
在得到Fragment之後，我用下面的代碼。
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();
我也管理了backstack。那裏沒有問題。唯一的問題是視圖不可見。即使列表中包含項目，並且ListView也會與適配器一起完成初始化。
被修改：
我除去notifiyDataSetChanged（）和i設置適配器每次。現在它工作正常。