android navigation component reload fragment , and observe mutable data again when navigate back from fragment to fragment , I tried single observe listener but nothing happen keep reloading and hitting api again
public class TermsFragment extends Fragment {
private TermsViewModel termsViewModel;
private FragmentTermsBinding binding;
public View onCreateView(@NonNull LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
termsViewModel = new ViewModelProvider(this).get(TermsViewModel.class);
termsViewModel.init(getContext());
binding = FragmentTermsBinding.inflate(inflater, container, false);
termsViewModel.terms.observe(getViewLifecycleOwner(), terms -> {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
binding.terms.setText(Html.fromHtml(terms.replaceAll("<img.+?>", ""), Html.FROM_HTML_MODE_COMPACT));
} else {
binding.terms.setText(Html.fromHtml(terms.replaceAll("<img.+?>", "")));
}
});
View root = binding.getRoot();
return root;
}
@Override
public void onDestroyView() {
super.onDestroyView();
binding = null;
}
}
and my viewmodel Class
public class TermsViewModel extends ViewModel implements Onresponse {
public MutableLiveData<String> terms;
Context context=null;
public TermsViewModel() {
terms = new MutableLiveData<>();
}
public void init(Context context){
this.context=context;
Map<String,Object> body=new HashMap<>();
body.put("st", Api.app_data);
body.put("id",1);
body.put("lg",Constant.langstr);
Constant.connect(context,Api.app_data,body,this::onResponse,false);
}
@Override
public void onResponse(String st, JSONObject object, int online) {
if(object!=null) {
try {
terms.setValue(object.getString("data"));
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}
When you navigate back and forth the view does not survive but the fragment does . Thus you can move any initialization code to onCreate
instead of onCreateView
. onCreate
is called once per fragment's lifetime.
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
termsViewModel = new ViewModelProvider(this).get(TermsViewModel.class);
termsViewModel.init(getContext());
}
This way you will:
init
only once in a lifetime of this fragment.
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