在碎片之间切换时，循环消失

Question

我在DashboardActivity中有四个片段。我在HomeFragment中有回收视图，它是首先加载的默认页面。循环视图第一次出现，但当我切换到另一个片段并再次进入HomeFragment时，它就消失了。这是我的DashbaordActivity。

public class DashboardActivity extends AppCompatActivity {
// views
private BottomNavigationView bottomNav;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_dashboard);
bottomNav = findViewById(R.id.bottom_nav);
bottomNav.setOnNavigationItemSelectedListener(bottomNavMethod);
getSupportFragmentManager().beginTransaction().replace(R.id.container, new HomeFragment()).commit() ;
}
// click event listener
private BottomNavigationView.OnNavigationItemSelectedListener bottomNavMethod =
new BottomNavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
Fragment fragment =null;
switch (item.getItemId()) {
case R.id.home:
fragment = new HomeFragment();
break;
case R.id.chat:
fragment = new ChatFragment();
break;
case R.id.map:
fragment = new MapsFragment();
break;
case R.id.users:
fragment = new UserFragment();
break;
}
getSupportFragmentManager().beginTransaction().replace(R.id.container, fragment).commit();
return true;
}
};
}

这是我的HomeFragment

public class HomeFragment extends Fragment {
// views
private View homeView;
private RecyclerView childList;
private Adapter adapter;
// variables
private IAPI api;
private CompositeDisposable compositeDisposable = new CompositeDisposable();
private SharedPreferences preferences;
private List<Child> cList = new ArrayList<>();
private Integer image = R.drawable.avatar;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
homeView = inflater.inflate(R.layout.fragment_home, container, false);
preferences = getActivity().getSharedPreferences(Constatnt.MY_PREFERENCE, Context.MODE_PRIVATE);
api = RetrofitClient.getInstance().create(IAPI.class);
childList = homeView.findViewById(R.id.child_rec_view);
adapter = new Adapter(getContext(), cList, image);
GridLayoutManager gridLayoutManager = new GridLayoutManager(getContext(), 2, GridLayoutManager.VERTICAL, false);
childList.setLayoutManager(gridLayoutManager);
childList.setAdapter(adapter);
return homeView;
}
private void getChildren() {
int parentId = preferences.getInt("Id", 0);
compositeDisposable.add(api.getChildren(parentId)
.subscribeOn(Schedulers.io())
.observeOn(Schedulers.io())
.subscribe(new Consumer<List<Child>>() {
@Override
public void accept(List<Child> children) throws Exception {
for (Child c:children) {
cList.add(c);
}
}
}));
}
@Override
public void onStart() {
super.onStart();
getChildren();
}
}

问题是什么，我如何解决？

Answer 1

覆盖

onViewCreated((

并在此方法中添加设置适配器

childList = view.findViewById(R.id.child_rec_view);
adapter = new Adapter(getContext(), cList, image);
GridLayoutManager gridLayoutManager = new GridLayoutManager(getContext(), 2, GridLayoutManager.VERTICAL, false);
childList.setLayoutManager(gridLayoutManager);
childList.setAdapter(adapter);