Question

我在后台堆上获得NPE。为了解决OOM问题，我读到我需要取消Fragment内的所有引用，尤其是Bitmaps。所以我所做的是：当Fragment被替换时，我将每个变量设置为null，除了Adapter RecyclerView，因为我需要再次使用该内容。

@Override
public void onDestroyView() {
    super.onDestroyView();
    annihilateView();
}

onCreateView：

@Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        rootView = inflater.inflate(R.layout.fragment_lobi, container, false);
        getActivity().getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
        utilities = new Utilities(BottomLobiFragment.this.getActivity());

        ((NewsfeedActivity)getActivity()).hideBottomToolbarMarket();
        setHasOptionsMenu(true);
        userIdString = sharedPreferencesList.userIDString;
        userAliasString = sharedPreferencesList.userAliasString;
        loginSharedPrefsString = sharedPreferencesList.loginSharedPreference;
//        mPrefs = getContext().getSharedPreferences(loginSharedPrefsString, getContext().MODE_PRIVATE);

        userId = sharedPreferenceUtilities.getValue(BottomLobiFragment.this.getActivity(), loginSharedPrefsString, userIdString);
        userAlias = sharedPreferenceUtilities.getValue(BottomLobiFragment.this.getActivity(), loginSharedPrefsString, userAliasString);

        lobiProgressBar = (ProgressBar)rootView.findViewById(R.id.fragment_lobi_progressBar);
        lobiProgressBar.getIndeterminateDrawable().setColorFilter(
                getResources().getColor(R.color.miBlue),
                android.graphics.PorterDuff.Mode.SRC_IN);
        noPostTV = (OpenSansFont)rootView.findViewById(R.id.fragment_lobi_noPostTextView);

        recyclerView = (RecyclerView)rootView.findViewById(R.id.fragment_lobi_recyclerView);

        handler = new Handler();
        manager = new LinearLayoutManager(BottomLobiFragment.this.getActivity(),
                LinearLayoutManager.VERTICAL,
                false);
        recyclerView.setLayoutManager(manager);
//        recyclerView.getRecycledViewPool().setMaxRecycledViews(VIEW_TYPE,0);
        swipeRefreshLayout = (SwipeRefreshLayout)rootView.findViewById(R.id.fragment_lobi_swipe_container);
        swipeRefreshLayout.setOnRefreshListener(this);

        width = displayMetrics.widthPixels;
        height = displayMetrics.heightPixels;

        upperToolbarInit();

        if(getArguments() != null){
            Parcelable savedRecyclerLayoutState = getArguments().getParcelable(utilities.BUNDLE_RECYCLER_LAYOUT);
            if(savedRecyclerLayoutState == null){
                Gson gson = new Gson();
                String json = sharedPreferenceUtilities.getValue(BottomLobiFragment.this.getActivity(), sharedPreferencesList.loginSharedPreference, utilities.lobbyPostListKey);
                //(utilities.lobbyPostListKey, "");
                PostListSharedPrefs postListApiFrmJson = gson.fromJson(json, PostListSharedPrefs.class);
                if(postListApiFrmJson != null){
                    lobiAdapter = new LobiAdapter();
                    lobiAdapter.setDisplay(width, height);
                    recyclerView.setAdapter(lobiAdapter);
                    recyclerView.setLayoutManager(manager);
                    lobiAdapter.addList(postListApiFrmJson.posts);
                    counter += postListApiFrmJson.posts.size();
                    setIsLoaded();
                    setBlankLoaded();
                } else {
                    refreshView();
                }
            } else {
                manager.onRestoreInstanceState(savedRecyclerLayoutState);
                recyclerView.setAdapter(lobiAdapter);
                recyclerView.setLayoutManager(manager);
                lobiProgressBar.setVisibility(View.GONE);
            }
        } else if(getArguments() == null){
            refreshView();
        }

问题是，每次用户根据Fragment Lifecycle进行backstack时都应该再次调用onCreateView，是吗？因为我已经引用了onCreateView中的所有内容并且它会抛出NPE，但如果我没有在onDestroyView中将所有内容都设置为null，那么它可以正常工作......或者我只是在阅读生命周期错误？

Android - Backstack上的Null Pointer异常

0 个答案: