Java 导航抽屉后压碎片不'；t载荷

我有一个带有碎片的

导航抽屉。开始时，我默认显示
Home fragment

导航菜单上有一些选项。在2个片段中，我有
SwipeRefreshLayout
。在提取所有的
recyclerview
数据之前，我将显示数据和不可见的
SwipeRefreshLayout

其中一个片段（包括
SwipeRefReshLayout
）工作正常，但在主片段中出现了一些问题

例如（用例）

您启动了应用程序，看到了Home fragment

您单击了导航菜单上的配置文件片段

您可以按后退按钮（后退按钮）运行

在这种情况下，数据永远不会加载，布局总是旋转。（我也试过不刷新布局，还是一样）

你知道怎么解决这个问题吗？我的想法是，它是关于显示默认片段的

Fragment fragment;

public void displayDefaultFragment() {
    fragment = new Nav_Home();
    fragmentManager.beginTransaction().replace(R.id.navContent, fragment).commit();
}

public void showProfileFragment() {
    fragment = new Nav_Profile();
    fragmentManager.beginTransaction().replace(R.id.navContent, fragment).addToBackStack(null).commit();
}

导航抽屉活动

public class Page_Navigation extends AppCompatActivity
    implements NavigationView.OnNavigationItemSelectedListener {

    Fragment fragment;
    FragmentManager fragmentManager = getSupportFragmentManager();
    NavigationView navigationView;

    SharedPreferences mSharedPref;
    DrawerLayout drawer;
    private Tracker mTracker;
    FragmentTransaction fragmentTransaction;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_page__navigation);

        //
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        TextView toolbar_head = findViewById(R.id.toolbar_head);
        ImageView toolbar_image = findViewById(R.id.toolbar_image);
        ImageView toolbar_profile = findViewById(R.id.toolbar_profile);
        drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        //

        AnalyticsApplication application = (AnalyticsApplication) getApplication();
        mTracker = application.getDefaultTracker();
        mTracker.setScreenName("page_navigation");
        mTracker.send(new HitBuilders.ScreenViewBuilder().build());


        //FIRST SETTINGS
        setSupportActionBar(toolbar);
        Typeface customFont = Typeface.createFromAsset(getAssets(), "Montserrat-Medium.ttf");
        toolbar_head.setTypeface(customFont);

        //Get Sessions
        mSharedPref = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
        String session_user_name = mSharedPref.getString("session_user_name", "");
        String session_user_photo = mSharedPref.getString("session_user_photo", "");

        //Navigation Drawer
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.addDrawerListener(toggle);
        toggle.syncState();

        navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);
        navigationView.setItemIconTintList(null);
        //

        View headerView = navigationView.getHeaderView(0);
        TextView nav_userName = (TextView) headerView.findViewById(R.id.textView_nav_userName);
        CircleImageView imageView_navigation = (CircleImageView) headerView.findViewById(R.id.imageView_navigation);
        Glide.with(getApplicationContext()).load(session_user_photo).into(imageView_navigation);
        nav_userName.setText(session_user_name);

        headerView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (drawer.isDrawerOpen(Gravity.START)) {
                    drawer.closeDrawer(Gravity.START);
                }

                new Handler().postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        showProfileFragment();
                    }
                }, 300);
            }
        });


        toolbar_image.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                drawer.openDrawer(GravityCompat.START);
            }
        });

        toolbar_profile.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Fragment fragment;
                FragmentManager manager = getSupportFragmentManager();
                fragment = new Nav_Profile();
                fragmentTransaction = manager.beginTransaction();
                fragmentTransaction.replace(R.id.navContent, fragment).addToBackStack(null).commit();
            }
        });

        displayDefaultFragment();

    }

    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.page__navigation, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }


        return super.onOptionsItemSelected(item);
    }

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {
        // Handle navigation view item clicks here.

        final int id = item.getItemId();


        drawer.closeDrawer(GravityCompat.START);

        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                switch (id) {
                    case R.id.nav_home:
                        fragment = new Nav_Home();
                        break;

                    case R.id.nav_contact:
                        fragment = new Nav_Contact();
                        break;

                    case R.id.nav_articles:
                        fragment = new Nav_Article();
                        break;

                    case R.id.nav_about:
                        fragment = new Nav_AboutUs();
                        break;

                    case R.id.nav_suggest:
                        fragment = new Nav_Suggest();
                        break;

                    case R.id.nav_share:
                        fragment = new Nav_Share();
                        break;

                    case R.id.nav_rateApp:
                        fragment = new Nav_RateApp();
                        break;


                }

                fragmentManager.beginTransaction()
                        .replace(R.id.navContent, fragment)
                        .addToBackStack(null)
                        .commit();

            }
        }, 350);


        return true;
    }

    public void displayDefaultFragment() {
        fragment = new Nav_Home();
        fragmentManager.beginTransaction().replace(R.id.navContent, fragment).commit();

    }


    public void showProfileFragment() {
        fragment = new Nav_Profile();
        fragmentManager.beginTransaction().replace(R.id.navContent, fragment).addToBackStack(null).commit();
    }
}

主片段

public class Nav_Home extends Fragment implements View.OnClickListener{

    SharedPreferences mSharedPref;

    private SwipeRefreshLayout swipeRefresh_home;

    private CardView item_homeTop_coupons, item_homeTop_draws, item_homeTop_event;
    private LinearLayout layout_all_article, layout_all_999;
    private ScrollView shimmer_home;

    private List<Model_ListItem> listNewItems;
    private RecyclerView recyclerView_item_home;

    private List<Model_Article> articleList;
    private RecyclerView recyclerView_article_home;

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        fetchItemsNew();
        fetchArticlesNew();
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment

        View view = inflater.inflate(R.layout.fragment_nav__home, container, false);
        item_homeTop_coupons = view.findViewById(R.id.item_homeTop_coupons);
        item_homeTop_draws = view.findViewById(R.id.item_homeTop_draws);
        item_homeTop_event = view.findViewById(R.id.item_homeTop_event);
        recyclerView_item_home = view.findViewById(R.id.recyclerView_item_home);
        recyclerView_article_home = view.findViewById(R.id.recyclerView_article_home);
        layout_all_article = view.findViewById(R.id.layout_all_article);
        layout_all_999 = view.findViewById(R.id.layout_all_999);
        swipeRefresh_home = view.findViewById(R.id.swipeRefresh_home);
        shimmer_home = view.findViewById(R.id.shimmer_home);
        item_homeTop_coupons.setOnClickListener(this);
        item_homeTop_draws.setOnClickListener(this);
        item_homeTop_event.setOnClickListener(this);
        layout_all_999.setOnClickListener(this);
        layout_all_article.setOnClickListener(this);

        //first settngs
        mSharedPref = PreferenceManager.getDefaultSharedPreferences(view.getContext());
        String session_user_email = mSharedPref.getString("session_user_email","");


        swipeRefresh_home.setRefreshing(true);
        return view;
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){

            case R.id.item_homeTop_coupons:
                startActivity(new Intent(getContext(), Page_Coupon.class));
                break;

            case R.id.item_homeTop_draws:
                startActivity(new Intent(getContext(), Page_Draw.class));
                break;

            case R.id.item_homeTop_event:
                startActivity(new Intent(getContext(), Page_Event.class));
                break;

            case R.id.layout_all_999:
                //999 city search activity
                startActivity(new Intent(getContext(), Page_SearchCity.class));
                break;

            case R.id.layout_all_article:
                //article fragment
                Fragment fragment;
                FragmentManager fragmentManager = getFragmentManager();
                fragment = new Nav_Article();
                fragmentManager.beginTransaction().replace(R.id.navContent, fragment).addToBackStack(null).commit();
                break;

        }
    }



    public void fetchItemsNew(){
        listNewItems = new ArrayList<>();
        API_Service api_service = Client.getRetrofitInstance().create(API_Service.class);
        Call<List<Model_ListItem>> call = api_service.fetchItemsNew();
        call.enqueue(new Callback<List<Model_ListItem>>() {
            @Override
            public void onResponse(Call<List<Model_ListItem>> call, Response<List<Model_ListItem>> response) {

                if(response.code() == 200){

                    listNewItems = response.body();
                    Adapter_HomeItem adapter_homeItem = new Adapter_HomeItem(getContext(), listNewItems);
                    LinearLayoutManager layoutManager
                            = new LinearLayoutManager(getContext(), LinearLayoutManager.HORIZONTAL, false);
                    recyclerView_item_home.setHasFixedSize(true);
                    recyclerView_item_home.setLayoutManager(layoutManager);
                    recyclerView_item_home.setAdapter(adapter_homeItem);

                    SnapHelper helper = new LinearSnapHelper();
                    helper.attachToRecyclerView(recyclerView_item_home);

                }

            }

            @Override
            public void onFailure(Call<List<Model_ListItem>> call, Throwable t) {

            }
        });

    }

    public void fetchArticlesNew(){
        articleList = new ArrayList<>();
        API_Service api_service = Client.getRetrofitInstance().create(API_Service.class);
        Call<List<Model_Article>> callArticle = api_service.fetchArticlesNew();
        callArticle.enqueue(new Callback<List<Model_Article>>() {
            @Override
            public void onResponse(Call<List<Model_Article>> call, Response<List<Model_Article>> response) {

                if(response.code() == 200){

                    articleList = response.body();
                    Adapter_HomeArticles adapter_homeArticles = new Adapter_HomeArticles(getContext(), articleList);
                    LinearLayoutManager layoutManager
                            = new LinearLayoutManager(getActivity(), LinearLayoutManager.HORIZONTAL, false);
                    recyclerView_article_home.setLayoutManager(layoutManager);
                    recyclerView_article_home.setHasFixedSize(true);
                    recyclerView_article_home.setAdapter(adapter_homeArticles);


                }

            }

            @Override
            public void onFailure(Call<List<Model_Article>> call, Throwable t) {

            }
        });

    }
}

公共类Nav_Home扩展片段实现View.OnClickListener{
共享引用mSharedPref；
私人swipeRefresh布局swipeRefresh_home；
私人卡查看项目\主页\优惠券、项目\主页\抽奖、项目\主页\活动；
私人线路布局布局所有文章，布局所有999；
私人ScrollView shimmer_主页；
私有列表项；
私人回收站查看回收站查看物品；
私人物品清单；
私人回收站查看回收站查看文章；
@凌驾
创建时的公共void（@Nullable Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
fetchItemsNew（）；
fetchArticlesNew（）；
}
@凌驾
创建视图上的公共视图（布局、充气机、视图组容器、，
Bundle savedInstanceState）{
//为该碎片膨胀布局
视图=充气机。充气（R.layout.fragment\u nav\u home，container，false）；
item\u homeTop\u优惠券=view.findViewById（R.id.item\u homeTop\u优惠券）；
item\u homeTop\u draws=view.findViewById（R.id.item\u homeTop\u draws）；
item\u homeTop\u event=view.findviewbyd（R.id.item\u homeTop\u event）；
recyclerView\u item\u home=view.findViewById（R.id.recyclerView\u item\u home）；
recyclerView\u article\u home=view.findviewbyd（R.id.recyclerView\u article\u home）；
layout\u all\u article=view.findviewbyd（R.id.layout\u all\u article）；
layout_all_999=view.findviewbyd（R.id.layout_all_999）；
swipeRefresh\u home=view.findViewById（R.id.swipeRefresh\u home）；
shimmer_home=view.findviewbyd（R.id.shimmer_home）；
item_homeTop_优惠券。setOnClickListener（此）；
item_homeTop_draws.setOnClickListener（此）；
item_homeTop_event.setOnClickListener（此）；
布局_all _999.setOnClickListener（此）；
布局所有文章。setOnClickListener（此）；
//第一组
mSharedPref=PreferenceManager.getDefaultSharedReferences（view.getContext（））；
String session\u user\u email=mSharedPref.getString（“session\u user\u email”，”）；
swipeRefresh_home.setRefreshing（true）；
返回视图；
}
@凌驾
公共void onClick（视图v）{
开关（v.getId（））{
案例R.id.item\u homeTop\u优惠券：
startActivity（新的意图（getContext（），Page_consupt.class））；
打破
案例R.id.item\u homeTop\u图纸：
startActivity（新意图（getContext（），Page_Draw.class））；
打破
案例R.id.item\u homeTop\u事件：
startActivity（新意图（getContext（），Page_Event.class））；
打破
案例R.id.Layou all_999：
//999城市搜索活动
startActivity（新意图（getContext（），Page_SearchCity.class））；
打破
案例R.id.Layou所有文章：
//文章片段
片段；
FragmentManager FragmentManager=getFragmentManager（）；
片段=新的导航文章（）；
fragmentManager.beginTransaction（）.replace（R.id.navContent，fragment）.addToBackStack（null.commit（）；
打破
}
}
public void fetchItemsNew（）{
listNewItems=newArrayList（）；
API_服务API_服务=Client.getInstance（）.create（API_服务.class）；
Call Call=api_service.fetchItemsNew（）；
call.enqueue（新回调（）{
@凌驾
公共void onResponse（调用、响应）{
if（response.code（）==200）{
listNewItems=response.body（）；
Adapter\u HomeItem Adapter\u HomeItem=新适配器\u HomeItem（getContext（），listNewItems）；
直线布局经理布局经理
=新的LinearLayoutManager（getContext（），LinearLayoutManager.HORIZONTAL，false）；
recyclerView\u item\u home.setHasFixedSize（true）；
recyclerView_item_home.setLayoutManager（layoutManager）；
recyclerView\u item\u home.setAdapter（适配器\u home项）；
SnapHelper helper=新的LinearSnapHelper（）；
helper.attachToRecyclerView（recyclerView\u item\u home）；
}
}
@凌驾
失败时公共无效（调用调用，可丢弃的t）{
}
});
}
public void fetchArticlesNew（）{
articleList=新的ArrayList（）；
API_服务API_服务=Client.getInstance（）.create（API_服务.class）；
调用callArticle=api_service.fetchArticlesNew（）；
enqueue（新回调（）{
@凌驾
公共void onResponse（调用、响应）{
if（response.code（）==200）{
articleList=response.body（）；
Adapter\u HomeArticles Adapter\u HomeArticles=新适配器\u HomeArticles（getC
Fragment fragment;

public void displayDefaultFragment() {
    fragment = new Nav_Home();
    fragmentManager.beginTransaction().replace(R.id.navContent, fragment).commit();
}

public void showProfileFragment() {
    fragment = new Nav_Profile();
    fragmentManager.beginTransaction().replace(R.id.navContent, fragment).addToBackStack(null).commit();
}

Fragment homeFragment;
Fragment profileFragment;

public void displayDefaultFragment() {
    homeFragment = new Nav_Home();
    fragmentManager.beginTransaction().replace(R.id.navContent, homeFragment).commit();
}

public void showProfileFragment() {
    profileFragment = new Nav_Profile();
    fragmentManager.beginTransaction().replace(R.id.navContent, profileFragment).addToBackStack(null).commit();
}