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Ludiras
Asked: 2020-10-13 04:09:55 +0800 CST 2020-10-13 04:09:55 +0800 CST

Checkbox does not survive rotate screen changes

  • 772

I have an application that I am making in order to practice MVVM. What this application does is simply call Retrofit and paint the data from a JSON into a RecyclerView. In the row of the RecyclerView I have a checkbox whose functionality is that if it is marked, pressing a button with u shows me those marked elements in another RecyclerView of another fragment. The problem is that when I mark a check, before sending it or anything, if I turn the screen, it's like the list is reloaded or I don't know very well what behavior it is doing, but the fact is that that checkbox is unchecked again and I want that even though I haven't sent those changes to Retrofit yet, that checkbox press remains:

This is my class for the view:

package com.example.menunavegacion.ui.fragments.tabs.fragmentpets.view;

....

public class FragmentPets extends Fragment {

    @BindView(R.id.recyclerView)
    RecyclerView recyclerView;
    @BindView(R.id.progressBar)
    ProgressBar progressBar;

    PetsViewModel mWordViewModel;
    PetsAdapter adapter;

    @Inject
    RequestInterface requestInterface;

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.fragment_tab_one, container, false);
        ButterKnife.bind(this, v);
        initViews();
        return v;
    }

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        mWordViewModel = ViewModelProviders.of(this).get(PetsViewModel.class);

        mWordViewModel.getAllPets().observe(this, new Observer<ArrayList<PetsDTO>>() {
            @Override
            public void onChanged(ArrayList<PetsDTO> petsDTOS) {
                adapter = new PetsAdapter(petsDTOS, getContext(), false);
                recyclerView.setAdapter(adapter);
            }
        });

        mWordViewModel.getLoadingLiveData().observe(this, new Observer<Boolean>() {
            @Override
            public void onChanged(Boolean loading) {
                if (loading) {
                    progressBar.setVisibility(View.VISIBLE);
                } else {
                    progressBar.setVisibility(View.GONE);
                }
            }
        });

        mWordViewModel.loadJSON();

        mWordViewModel.showFinishMessage().observe(this, new Observer<Boolean>() {
            @Override
            public void onChanged(Boolean aBoolean) {
                if (aBoolean) {
                    Toast.makeText(getActivity(), getActivity().getString(R.string.update_toast_message), Toast.LENGTH_SHORT).show();
                } else {
                    Toast.makeText(getActivity(), getActivity().getString(R.string.message_send_error), Toast.LENGTH_SHORT).show();
                }
            }
        });
    }

    @OnClick(R.id.btnSend)
    public void onSend() {
        mWordViewModel.updateList(adapter.getPetList());
    }

    private void initViews() {
        recyclerView.setHasFixedSize(true);
        RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getContext());
        recyclerView.setLayoutManager(layoutManager);
    }
}

This is my ViewModel:

package com.example.menunavegacion.ui.fragments.tabs.fragmentpets.viewmodel;

....

public class PetsViewModel extends AndroidViewModel implements ViewModelInterface.ViewModel {

    private PetsRepository mPetsRepository;
    private LiveData<ArrayList<PetsDTO>> mAllPets;

    public PetsViewModel (Application application){
        super(application);
        mPetsRepository = new PetsRepository(application);
        mAllPets = mPetsRepository.getAllPetsLiveData();
    }

    public LiveData<ArrayList<PetsDTO>> getAllPets() {
        return mPetsRepository.getAllPetsLiveData();
    }

    public LiveData<Boolean> getLoadingLiveData() {
        return mPetsRepository.getLoadingLiveData();
    }

    public LiveData<Boolean> showFinishMessage() {
        return mPetsRepository.getFinishMessage();
    }


    @Override
    public void loadJSON() {
        mPetsRepository.useCaseLoadJSON();
    }

    @Override
    public void updateList(ArrayList<PetsDTO> pets) {
        mPetsRepository.useCaseUpdateList(pets);
    }
}

This is the repository:

package com.example.menunavegacion.ui.fragments.tabs;

....

public class PetsRepository {

    LoadJSONUseCase loadJSONUseCase;
    UpdateListUseCase updateListUseCase;

    private MutableLiveData<ArrayList<PetsDTO>> allPetsLiveData = new MutableLiveData<>();
    private MutableLiveData<Boolean> loadingLiveData = new MutableLiveData<>();
    private MutableLiveData<Boolean> showFinishMessage = new MutableLiveData<>();

    public LiveData<ArrayList<PetsDTO>> getAllPetsLiveData() {
        return allPetsLiveData;
    }
    public LiveData<Boolean> getLoadingLiveData() {
        return loadingLiveData;
    }
    public LiveData<Boolean> getFinishMessage() {
        return showFinishMessage;
    }

    public PetsRepository(Application application) {
        loadJSONUseCase = new LoadJSONUseCase();
        updateListUseCase = new UpdateListUseCase();
    }

    public void useCaseLoadJSON() {
        loadJSONUseCase.loadJSON(new RepositoryInterface() {
            @Override
            public void showError(Boolean show) {
                showFinishMessage.postValue(show);
            }

            @Override
            public void onLoading(boolean loading) {
                loadingLiveData.postValue(loading);
            }

            @Override
            public void onSuccess(ArrayList<PetsDTO> data) {
                allPetsLiveData.postValue(data);
            }
        });
    }

    public void useCaseUpdateList(ArrayList<PetsDTO> pets) {
        updateListUseCase.updateList(pets, new RepositoryInterface() {
            @Override
            public void showError(Boolean show) {
                showFinishMessage.postValue(show);
            }

            @Override
            public void onLoading(boolean loading) {
                loadingLiveData.postValue(loading);
            }

            @Override
            public void onSuccess(ArrayList<PetsDTO> data) {
                allPetsLiveData.postValue(pets);
            }
        });
    }

}

This is my usecase that is responsible for loading the Retrofit JSON:

package com.example.menunavegacion.ui.fragments.usecase;

....

public class LoadJSONUseCase {

    @Inject
    RequestInterface requestInterface;

    public LoadJSONUseCase(){
        DaggerComponenTest.builder().build().inject(this);
    }

    public void loadJSON(RepositoryInterface repositoryInterface) {
        Call<JSONResponse> call = requestInterface.getJSON();
        repositoryInterface.onLoading(true);
        call.enqueue(new Callback<JSONResponse>() {
            @Override
            public void onResponse(Call<JSONResponse> call, Response<JSONResponse> response) {
                repositoryInterface.onLoading(false);
                JSONResponse jsonResponse = response.body();
                ArrayList<PetsDTO> data = new ArrayList<>();
                data.clear();
                data.addAll(jsonResponse.getPetsDTO());
                repositoryInterface.onSuccess(data);
            }

            @Override
            public void onFailure(Call<JSONResponse> call, Throwable t) {
               repositoryInterface.onLoading(false);
               repositoryInterface.showError(false);
            }
        });

    }
}

This would be all my code. I also accept advice about MVVM since I'm learning and well, they're welcome, so I'll stay with you. Thank you very much.

java

2 Answers

  1. This has to do with how Android handles the Activities lifecycle , basically when you rotate the screen Android "destroys" the activity and then recreates it, this removes any state from the UI. I can think of two ways to fix it, the first one is the simplest and the second one is a bit tricky:

    Solution 1: You can restrict the screen orientation of that activity, by adding android:screenOrientation="portrait" in the AndroidManifest.xml , that activity will only look vertical and thus avoid losing the state of the checkbox:

    <activity
            android:name=".MainActivity"
            android:screenOrientation="portrait"> <!-- Solo en Vertical -->
            .....
</activity>

    Solution 2: You can fix it using, in the activity where that code is executed, the onSaveInstanceState() method with this you can save the state of the checkbox in a Bundle :

    @Override
public void onSaveInstanceState(Bundle savedInstanceState) {
   // Guardar el estado del checkbox
   savedInstanceState.putInt(ESTADO_CHECKBOX, estadoCheckBox);

   // Always call the superclass so it can save the view hierarchy state
   super.onSaveInstanceState(savedInstanceState);
}

    And to recover it, you use the onRestoreInstanceState() method in the same activity :

    @Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
    // Always call the superclass so it can restore the view hierarchy
    super.onRestoreInstanceState(savedInstanceState);

    // Recuperar el estado de los checkboxs
    estadoCheckBox = savedInstanceState.getInt(ESTADO_CHECKBOX);
}

    Although also in the documentation it is mentioned that the Bundle can be retrieved in the onCreate() method, but it is necessary to verify that the bundle savedIntanceState is not null .

    • 1
  2. Best Answer

    You can try to save your fix to the bundle and retrieve it after rotating the screen.

    First you need your PetsDTO model to implement Parcelable and implement the necessary methods:

    public class PetsDTO implements Parcelable {
...
}

    Then in your snippet use the onSaveInstanceState methods to save the current state of your list to the Bundle:

    @Override
public void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    outState.putParcelableArrayList("list", petsDTOS);
}

    In your inViewCreated() retrieve the arrayList saved in the Bundle:

    if (savedInstanceState != null){
    //Recupera la lista del Bundle
    petsDTOS = savedInstanceState.getParcelableArrayList("list");
}else{
    //llena tu lista
}

    And in your Activiy you also need to save the state of the fragment using the OnCreate and onSaveInstanceState methods:

    Fragment fragment;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    ...

    if (savedInstanceState != null ) {
        getSupportFragmentManager().getFragment(savedInstanceState, "fragment");
    }else {
       fragment = new FragmentPets();
       getSupportFragmentManager().beginTransaction().replace(R.id.fragmen_layout, fragment).commit();
    }
}

@Override
public void onSaveInstanceState(Bundle outState, PersistableBundle outPersistentState) {
    super.onSaveInstanceState(outState, outPersistentState);
    getSupportFragmentManager().putFragment(outState, "fragment", fragment);
}

    I hope it helps you.

    • 1