打开另一个碎片时如何冻结碎片

Question

i使用Bottombar库制作应用程序。我正在使用

compile 'com.roughike:bottom-bar:2.0.2'

我有5个这样的片段

public class EventFragment extends Fragment {
    private RecyclerView rcEvent;
    private EventAdapter mAdapter;
    private List<EventModel> mgridData;
    private LinearLayoutManager layoutManager;
    private SwipeRefreshLayout mSwipe;

    public EventFragment() {
        // Required empty public constructor
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView= inflater.inflate(R.layout.fragment_event, container, false);
        mSwipe= (SwipeRefreshLayout) rootView.findViewById(R.id.swipeRefresh);
        rcEvent = (RecyclerView) rootView.findViewById(R.id.rv);
        layoutManager = new LinearLayoutManager(getActivity());
        rcEvent.setLayoutManager(layoutManager);
        mgridData = new ArrayList<>();
        mAdapter = new EventAdapter(getActivity(), mgridData);
        rcEvent.setAdapter(mAdapter);
        fetchData();
        mSwipe.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
            @Override
            public void onRefresh() {
                fetchData();
                //mSwipe.setRefreshing(false);
            }
        });
        return rootView;
    }
    public void fetchData()
    {
        mSwipe.setRefreshing(true);
        apiData api= ApiClient.getClient().create(apiData.class);
        Call<EventResponse> call=api.GetEvent();
        call.enqueue(new Callback<EventResponse>() {
            @Override
            public void onResponse(Call<EventResponse> call, Response<EventResponse> response) {
                if(response.isSuccessful())
                {
                    EventResponse result=response.body();
                    Log.d("Event", "response = " + new Gson().toJson(result));
                    if(result !=null)
                    {
                        List<EventModel> eventResponse= result.getEventData();
                        if(eventResponse !=null)
                        {
                            for (EventModel eventRespon :eventResponse) {
                                mgridData.add(eventRespon);
                            }
                            RecyclerView.Adapter adapter = new EventAdapter(getActivity(), mgridData);
                            mAdapter.setListData(mgridData);
                            rcEvent.setAdapter(adapter);
                        }
                        mSwipe.setRefreshing(false);
                    }
                }
            }
            @Override
            public void onFailure(Call<EventResponse> call, Throwable t) {
                Toast.makeText((MainActivity)getActivity(), "Koneksi Ke Internet Gagal", Toast.LENGTH_SHORT).show();
                mSwipe.setRefreshing(false);
            }
        });
    }
}

mainActivity.java

public class MainActivity extends AppCompatActivity {
    boolean doubleBackToExitPressedOnce = false;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //Declare Fragment
        final EventFragment eventFragment=new EventFragment();
        final BloodFragment bloodFragment=new BloodFragment();
        final MerchantFragment merchantFragment=new MerchantFragment();
        final StoreFragment storeFragment=new StoreFragment();
        final ProfileFragment profileFragment=new ProfileFragment();
        BottomBar bottomBar=(BottomBar) findViewById(R.id.bottomBar);
        bottomBar.setOnTabSelectListener(new OnTabSelectListener() {
            @Override
            public void onTabSelected(@IdRes int tabId) {
                if (tabId == R.id.tab_event) {
                    getSupportFragmentManager()
                            .beginTransaction()
                            .replace(R.id.contentContainer, eventFragment, eventFragment.getClass().getName())
                            .commit();
                }
                else if(tabId == R.id.tab_blood){
                    getSupportFragmentManager()
                            .beginTransaction()
                            .replace(R.id.contentContainer, bloodFragment, bloodFragment.getClass().getName())
                            .commit();
                }
                else if(tabId == R.id.tab_merchant){
                    getSupportFragmentManager()
                            .beginTransaction()
                            .replace(R.id.contentContainer, merchantFragment, merchantFragment.getClass().getName())
                            .commit();
                }
                else if(tabId == R.id.tab_store){
                    getSupportFragmentManager()
                            .beginTransaction()
                            .replace(R.id.contentContainer, storeFragment, storeFragment.getClass().getName())
                            .commit();
                }
                else if(tabId == R.id.tab_profile){
                    getSupportFragmentManager()
                            .beginTransaction()
                            .replace(R.id.contentContainer, profileFragment, profileFragment.getClass().getName())
                            .commit();
                }
            }
        });
    }
    @Override
    public void onResume() {
        super.onResume();
    }
    @Override
    public void onBackPressed() {
        if (doubleBackToExitPressedOnce) {
            super.onBackPressed();
            finish();
        }
        this.doubleBackToExitPressedOnce = true;
        Toast.makeText(this, "Please press BACK again to exit", Toast.LENGTH_SHORT).show();
        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                doubleBackToExitPressedOnce=false;
            }
        }, 2000);
    }
}

我的问题是，当我在第一个片段加载完成之前打开另一个片段时，我会遇到错误。发生错误是因为过程完成后，我处于另一个片段。因此，当我打开另一个碎片并再次打开片段时，我想使片段冻结。如何在我的代码中实现它？

Answer 1

解决方案是在打开新的片段时保存原始片段状态。

保存可以使用的片段状态：

@Override  
public void onActivityCreated(Bundle savedInstanceState) {
  super.onActivityCreated(savedInstanceState);
  ...
  if (savedInstanceState != null) {
    //Restore the fragment's state here
  }
}
@Override
public void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
   //Save the fragment's state here
}`