我的应用程序中有些障碍，其中包含一个包含ViewPager的片段。与适配器链接的ViewPager也包含一组片段。在我的应用程序中，HomeFragment是基本片段。当我运行应用程序时，一切正常，但片段未加载，仅显示ViewPager的标签，因此出现问题。
在这里，我共享基本片段，PageAdapter和fragment_home.xml文件的代码。
这是我的父片段代码： HomeFragment.java
public class HomeFragment extends Fragment {
Toolbar toolbar;
TabLayout tabLayout;
ViewPager viewPager;
PageAdapter pageAdapter;
TabItem tabChats;
TabItem tabStatus;
TabItem tabCalls;
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle saveInstanceState){
View root= inflater.inflate(R.layout.fragment_home, container, false);
toolbar = (Toolbar)root.findViewById(R.id.toolbar);
toolbar.setTitle(getResources().getString(R.string.app_name));
//setSupportActionBar(toolbar);
tabLayout = (TabLayout)root.findViewById(R.id.tablayout);
tabChats = (TabItem)root.findViewById(R.id.tabChats);
tabStatus = (TabItem)root.findViewById(R.id.tabStatus);
tabCalls = (TabItem)root.findViewById(R.id.tabCalls);
viewPager = (ViewPager)root.findViewById(R.id.viewPager);
pageAdapter = new PageAdapter(getChildFragmentManager(),tabLayout.getTabCount());
viewPager.setAdapter(pageAdapter);
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
return root;
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
Handler handler = new Handler();
handler.post(new Runnable() {
@Override
public void run() {
//------------
}
});
}
}
这是我的页面适配器代码： PageAdapter.java
public class PageAdapter extends FragmentPagerAdapter {
private int numOfTabs;
PageAdapter(FragmentManager fm, int tabCount) {
super(fm);
this.numOfTabs = numOfTabs;
}
@Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return new ChatFragment();
case 1:
return new StatusFragment();
case 2:
return new CallFragment();
default:
return null;
}
}
@Override
public int getCount() {
return numOfTabs;
}
}
这是XML文件： fragment_home.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="0dp"
android:background="?attr/colorPrimary"
android:minHeight="?attr/actionBarSize"
android:theme="?attr/actionBarTheme"
app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
app:theme="@style/ThemeOverlay.AppCompat.Dark" />
<android.support.design.widget.TabLayout
android:id="@+id/tablayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@color/colorPrimary"
app:tabSelectedTextColor="@android:color/white"
app:tabTextColor="@android:color/black">
<android.support.design.widget.TabItem
android:id="@+id/tabChats"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Chats" />
<android.support.design.widget.TabItem
android:id="@+id/tabStatus"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Status" />
<android.support.design.widget.TabItem
android:id="@+id/tabCalls"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Calls" />
</android.support.design.widget.TabLayout>
<android.support.v4.view.ViewPager
android:id="@+id/viewPager"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</RelativeLayout>
答案 0 :(得分：0)
我在我的项目中使用ButterKnife，所以如果您也不打算使用它，则可能要更改它。
public class HomeFragment extends Fragment {
@BindView(R.id.tabs)
TabLayout mTabLayout;
@BindView(R.id.pager)
ViewPager mPager;
View mView;
PagerAdapter mAdapter;
public MainFragment() {
// Required empty public constructor
}
static MainFragment fragment;
public static HomeFragment instance() {
if (fragment == null) {
fragment = new HomeFragment();
}
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container,
@Nullable Bundle savedInstanceState) {
// Inflate the layout for this fragment
mView = inflater.inflate(R.layout.fragment_home, container, false);
ButterKnife.bind(this, mView);
mPager.setAdapter(new PagerAdapter(getChildFragmentManager(), getActivity().getApplicationContext()));
mTabLayout.setupWithViewPager(mPager);
mTabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
@Override
public void onTabSelected(TabLayout.Tab tab) {
mPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
mPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
mPager.setCurrentItem(tab.getPosition());
}
});
return mView;
}
private class PagerAdapter extends FragmentStatePagerAdapter {
private String[] titles = {"Tab One", "Tab Two", "Tab Three"};
public PagerAdapter(FragmentManager manager, Context context) {
super(manager);
}
@Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return new TabOne();
case 1:
return new TabTwo();
case 2:
return new TabThree();
default:
return null;
}
}
@Override
public int getCount() {
return titles.length;
}
@Override
public CharSequence getPageTitle(int position) {
return titles[position];
}
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
}
@Override
public void onDetach() {
super.onDetach();
}
}
这是fragment_home.xml
<?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"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="55dp"
android:orientation="vertical">
<android.support.design.widget.AppBarLayout
android:id="@+id/appBarLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.design.widget.TabLayout
android:id="@+id/tabs"
app:tabTextColor="#FFFFFF"
app:tabSelectedTextColor="#FFFFFF"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="@+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior" />
</LinearLayout>