我已经设置了一个选项卡视图,每个选项卡都使用ViewPager具有自定义的片段。这是我的代码:
持有碎片
它的布局文件。
选项卡片段和其布局文件
我的标签适配器
处理代码。
有一些代码我省略了,但它与问题无关。 当最初查看该片段时,代码完美运行。然而,由于我的应用程序只包含一个活动并且仅替换每个导航到的片段的内容视图,因此每个片段都被添加到后退栈中,然后在按下后退按钮时弹出。我的问题是,当返回到这个片段时,选项卡内部的视图没有被填充,这意味着无法访问任何元素(因此,在尝试显示recyclerview等数据时,应用程序会崩溃)。
我查看了这个问题:TabLayout ViewPager Not Loading When Using Backstack并实施了它的建议(使用
希望得到帮助!
持有碎片
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_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.design.widget.TabLayout
android:id="@+id/inboxTabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabMode="scrollable" />
<com.pnikosis.materialishprogress.ProgressWheel
android:id="@+id/inbox_progress_wheel"
android:layout_width="80dp"
android:layout_height="80dp"
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_width="match_parent"
android:layout_height="0px"
android:layout_weight="1"
android:background="@android:color/white" />
</LinearLayout>
选项卡片段和其布局文件
<?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_width="match_parent"
android:layout_height="match_parent">
<com.baoyz.widget.PullRefreshLayout
android:id="@+id/tabPullRefresh"
android:layout_width="match_parent"
android:layout_height="match_parent">
<view
android:id="@+id/tabRecyclerHolder"
class="android.support.v7.widget.RecyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"
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_width="wrap_content"
android:layout_height="wrap_content"
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);
}
有一些代码我省略了,但它与问题无关。 当最初查看该片段时,代码完美运行。然而,由于我的应用程序只包含一个活动并且仅替换每个导航到的片段的内容视图,因此每个片段都被添加到后退栈中,然后在按下后退按钮时弹出。我的问题是,当返回到这个片段时,选项卡内部的视图没有被填充,这意味着无法访问任何元素(因此,在尝试显示recyclerview等数据时,应用程序会崩溃)。
我查看了这个问题:TabLayout ViewPager Not Loading When Using Backstack并实施了它的建议(使用
getChildFragmentManager()
设置页面适配器),但这并没有解决我的问题。希望得到帮助!
TabRecyclerHolder{ef0cb89 #0 id=0x7f0d00bd}
。它还显示pullrefresh也有一个对象实例。 然而,当导航到其他地方,然后通过片段堆栈返回时,它会给我这个:TabRecyclerHolder{1a8a8e64}
,对象内部的任何UI变量都为null。因此,看起来它没有再次填充视图。 - Matt Davis