Android TabLayout ViewPager 不会在 backstack 上膨胀标签片段
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【中文标题】Android TabLayout ViewPager 不会在 backstack 上膨胀标签片段【英文标题】:Android TabLayout ViewPager not inflating tab fragment on backstack 【发布时间】:2016-02-11 01:35:29 【问题描述】:我已经设置了一个选项卡视图,它使用 viewpager 为每个选项卡提供了自定义片段。这是我的代码:
持有片段
public class FragInboxMainView extends Fragment implements CGFragment
private CGController controller;
private CGFragment thisFragment;
@Bind(R.id.inboxViewPager)ViewPager inboxViewPager;
@Bind(R.id.inboxTabs)TabLayout inboxTabLayout;
@Bind(R.id.inbox_progress_wheel)ProgressWheel inboxProgressWheel;
public FragInboxMainView()
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
View rootView = inflater.inflate(R.layout.fragment_inbox_mainview, container, false);
ButterKnife.bind(this, rootView);
thisFragment = this;
Globals g = Globals.getInstance();
/** Show loading spinner */
this.inboxProgressWheel.setBarColor(ContextCompat.getColor(controller.getContext(), g.getUserObject().getUserThemeColor()));
this.inboxProgressWheel.setVisibility(View.VISIBLE);
/** Display the profile information based off the ID */
controller.displayInbox(thisFragment);
return rootView;
public void hideProgressSpinner()
this.inboxProgressWheel.setVisibility(View.GONE);
public ViewPager getInboxViewPager()
return this.inboxViewPager;
public TabLayout getInboxTabLayout()
return this.inboxTabLayout;
它的布局文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:wheel="http://schemas.android.com/apk/res-auto"
android:layout_
android:layout_
android:orientation="vertical">
<android.support.design.widget.TabLayout
android:id="@+id/inboxTabs"
android:layout_
android:layout_
app:tabMode="scrollable" />
<com.pnikosis.materialishprogress.ProgressWheel
android:id="@+id/inbox_progress_wheel"
android:layout_
android:layout_
android:layout_gravity="center"
wheel:matProg_barColor="#5588FF"
wheel:matProg_progressIndeterminate="true"
android:visibility="gone"/>
<android.support.v4.view.ViewPager
android:id="@+id/inboxViewPager"
android:layout_
android:layout_
android:layout_weight="1"
android:background="@android:color/white" />
</LinearLayout>
标签片段及其膨胀文件
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
android:id="@+id/main_content"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_
android:layout_>
<com.baoyz.widget.PullRefreshLayout
android:id="@+id/tabPullRefresh"
android:layout_
android:layout_>
<view
android:id="@+id/tabRecyclerHolder"
class="android.support.v7.widget.RecyclerView"
android:layout_
android:layout_
android:paddingTop="8dp"
android:paddingBottom="8dp"
android:clipToPadding="false"
android:layout_centerInParent="true"/>
</com.baoyz.widget.PullRefreshLayout>
<com.melnykov.fab.FloatingActionButton
android:id="@+id/tabFab"
android:layout_
android:layout_
android:layout_gravity="bottom|right"
android:layout_margin="16dp"
android:src="@mipmap/ic_add_white"/>
</android.support.design.widget.CoordinatorLayout>
public class TabRecyclerHolder extends Fragment
@Bind(R.id.tabRecyclerHolder) RecyclerView tabRecyclerHolder;
@Bind(R.id.tabPullRefresh) PullRefreshLayout tabPullRefresh;
@Bind(R.id.tabFab) FloatingActionButton recyclerFab;
private String tabTitle = "Title";
public TabRecyclerHolder()
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
View rootView = inflater.inflate(R.layout.tab_recycler_holder, container, false);
ButterKnife.bind(this, rootView);
recyclerFab.hide(false);
tabPullRefresh.setRefreshStyle(PullRefreshLayout.STYLE_MATERIAL);
return rootView;
public RecyclerView getTabRecyclerHolder()
return this.tabRecyclerHolder;
public FloatingActionButton getRecyclerFab()
return this.recyclerFab;
public String getTabTitle()
return this.tabTitle;
public void setTabTitle(String title)
this.tabTitle = title;
public PullRefreshLayout getTabPullRefresh()
return this.tabPullRefresh;
我的标签适配器
public class TabPagerAdapter extends FragmentStatePagerAdapter
private CGController controller;
private List<Object> items;
public TabPagerAdapter(FragmentManager fm, CGController controller, List<Object> items)
super(fm);
this.controller = controller;
this.items = items;
@Override
public int getCount()
return items.size();
@Override
public Fragment getItem(int num)
return (TabRecyclerHolder)items.get(num);
@Override
public String getPageTitle(int num)
return ((TabRecyclerHolder)items.get(num)).getTabTitle();
处理代码
public void viewInbox()
/** Set up the views */
receivedHolder = new TabRecyclerHolder();
receivedHolder.setTabTitle(Constants.TAB_INBOX_RECEIVED);
sentHolder = new TabRecyclerHolder();
sentHolder.setTabTitle(Constants.TAB_INBOX_SENT);
tabs.add(receivedHolder);
tabs.add(sentHolder);
/** Set up the tabs */
final ViewPager inboxViewPager = inboxFragment.getInboxViewPager();
TabLayout inboxTabLayout = inboxFragment.getInboxTabLayout();
/** Set the adapter for the view pager */
inboxViewPager.setAdapter(new TabPagerAdapter(inboxFragment.getChildFragmentManager(), controller, tabs));
/** set up the tab look and feel */
inboxTabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
inboxTabLayout.setTabMode(TabLayout.MODE_FIXED);
inboxViewPager.setOffscreenPageLimit(3);
inboxViewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(inboxTabLayout));
inboxTabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener()
@Override
public void onTabSelected(TabLayout.Tab tab)
inboxViewPager.setCurrentItem(tab.getPosition());
@Override
public void onTabUnselected(TabLayout.Tab tab)
@Override
public void onTabReselected(TabLayout.Tab tab)
);
/** And, display! */
inboxTabLayout.setupWithViewPager(inboxViewPager);
receivedAdapter = new RecyclerListAdapter(controller, items);
final RecyclerView receivedList = receivedHolder.getTabRecyclerHolder();
receivedList.setLayoutManager(new LinearLayoutManager(controller.getContext()));
receivedList.setAdapter(receivedAdapter);
我错过了一些代码,但它与问题无关。 最初查看片段时,代码运行良好。但是,由于我的应用程序包含一个活动,并且只是为导航到的每个片段替换了一个内容视图,因此每个片段都被添加到后退堆栈中,然后在按下后退按钮时弹出。我的问题是,当导航回这个片段时,选项卡内的视图没有被放大,这意味着无法访问任何元素(因此应用程序在尝试在 recyclerview 中显示数据时崩溃等)。
我看过这个问题:TabLayout ViewPager Not Loading When Using Backstack 并实施了它的建议(在设置寻呼机适配器时使用getChildFragmentManager()
),但这并没有解决我的问题。
我们将不胜感激!
【问题讨论】:
java.lang.NullPointerException 尝试访问应该在选项卡内膨胀的元素时。如果我删除任何试图访问内部片段的代码并让它显示而不会崩溃,它在选项卡内根本什么都没有显示。 pastebin.com/ECKF8VKg 该片段显示并显示了正在加载的微调器,但是当应用程序下载了所有数据并试图告诉微调器隐藏它时找不到它。 我已经删除了我的 cmets,以免打扰您的问题。尝试记录 viewInbox() 方法并确保在重新创建片段时调用它。 是的。我错过的部分代码执行 HTTP JSON 请求。后按时,它会处理 viewInbox() 中的所有内容,一直到尝试从 TabViewHolder() 设置拉动刷新。就好像它没有在 TabViewHolder 的新实例中膨胀视图,因此得到了 nullpointerexception。有没有办法在创建实例时强制它膨胀片段? 我不知道您的代码中发生了什么。最好的办法是在 viewInbox() 的开头设置一个断点,然后使用调试器单步执行代码以确保数据和片段都正常。 【参考方案1】:将此public View onCreateView(LayoutInflater inflater,...
更改为public void onViewCreated (View view, Bundle savedInstanceState)
所以你会有这样的东西
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
return inflater.inflate(R.layout.tab_recycler_holder, container, false);
然后
@Override
public void onViewCreated (View view, Bundle savedInstanceState)
ButterKnife.bind(this, view);
recyclerFab.hide(false);
tabPullRefresh.setRefreshStyle(PullRefreshLayout.STYLE_MATERIAL);
...
看看有没有帮助
【讨论】:
不幸的是没有运气 =(【参考方案2】:将 TabPagerAdapter 中的 FragmentStatePagerAdapter 扩展为
FragmentStatePagerAdapter(fragmentManager, BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT)
【讨论】:
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