ViewModel onchange gets called multiple times when back from Fragment

Question

I am working with Android architecture components. What i want is when user type "0" in Edittext and click on Button to replace Fragment with new one , and if type anything else post Toast error message. In Problem is when i back from new Fragment(BlankFragment) and click on button again and type "0" again and click, onchange() is called multiple times so Fragment is get created multiple times

FragmentExample.class:

     @Override     public View onCreateView(LayoutInflater inflater, ViewGroup container,                              Bundle savedInstanceState) {         manager = getActivity().getSupportFragmentManager();         viewmModel = ViewModelProviders.of(getActivity(), viewModelFactory)                 .get(VModel.class);          View v = inflater.inflate(R.layout.fragment_list, container, false);            b = (Button) v.findViewById(R.id.b);         et = (EditText) v.findViewById(R.id.et);          viewmModel.observeData().observe(getActivity(), new Observer<String>() {             @Override             public void onChanged(@Nullable String s) {                  if(s.equals("0")) {                     BlankFragment fragment = (BlankFragment) manager.findFragmentByTag(DETAIL_FRAG);                     if (fragment == null) {                         fragment = BlankFragment.newInstance();                     }                     addFragmentToActivity(manager,                             fragment,                             R.id.root_activity_detail,                             DETAIL_FRAG                     );                 } else {                     Toast.makeText(getContext(), "Wrong text", Toast.LENGTH_SHORT).show();                 }             }         });          b.setOnClickListener(new View.OnClickListener() {             @Override             public void onClick(View v) {                 viewmModel.setData(et.getText().toString());             }         });         return v;     }     private void addFragmentToActivity(FragmentManager fragmentManager, BlankFragment fragment, int root_activity_detail, String detailFrag) {         android.support.v4.app.FragmentTransaction transaction = fragmentManager.beginTransaction();         transaction.replace(root_activity_detail, fragment, detailFrag).addToBackStack(detailFrag);         transaction.commit();     } 

Repository class:

     public class Repository {     MutableLiveData<String> dataLive = new MutableLiveData<>();        public Repository() {      }      public void setListData(String data) {        dataLive.setValue(data);     }      public MutableLiveData<String> getData() {         return dataLive;     } } 

BlankFragment.class:

    @Override     public View onCreateView(LayoutInflater inflater, ViewGroup container,                              Bundle savedInstanceState) {          listItemViewModel = ViewModelProviders.of(this, viewModelFactory)                 .get(VModel.class);         listItemViewModel.setData("");         return inflater.inflate(R.layout.fragment_blank, container, false);     } 

Answer 1

Here is an example how i solve this problem .[TESTED AND WORKING]

 viewModel.getLoginResponse().observe(getViewLifecycleOwner(), new Observer<String>() {         @Override         public void onChanged(String response) {             if(getViewLifecycleOwner().getLifecycle().getCurrentState()== Lifecycle.State.RESUMED){                 // your code here ...             }          }     });