我有一个主要活动，它承载一个片段，该片段又承载一个 TabLayout（带有 ViewPager）。显示了选项卡栏，但未显示选项卡本身。
这是我在显示主机片段的主要活动中的代码：
Fragment fragment = new BMITabsFragment();
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction().replace(R.id.content_frame, fragment).addToBackStack(Constants.BMI_TABS_FRAGMENT).commit();
这是我托管 TabLayout 的 Fragment，即 BMITabsFragment (sa)：
public class BMITabsFragment extends Fragment {
...
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
// Get the ViewPager and set it's PagerAdapter so that it can display items
ViewPager viewPager = (ViewPager) view.findViewById(R.id.viewpager);
viewPager.setAdapter(new BMIFragmentPagerAdapter(getActivity().getSupportFragmentManager(),
getActivity()));
// Give the TabLayout the ViewPager
TabLayout tabLayout = (TabLayout) view.findViewById(R.id.sliding_tabs);
tabLayout.setupWithViewPager(viewPager);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_bmitabs, container, false);
return view;
}
...
}
这是我的 FragmentPagerAdapter：
public class BMIFragmentPagerAdapter extends FragmentPagerAdapter {
final int PAGE_COUNT = 2;
private FragmentManager fragmentManager;
private Context context;
public BMIFragmentPagerAdapter(FragmentManager fm, Context context) {
super(fm);
this.context = context;
this.fragmentManager = fm;
}
public BMIFragmentPagerAdapter(FragmentManager fm) {
super(fm);
fragmentManager = fm;
}
@Override
public CharSequence getPageTitle(int position) {
String[] pageTitles = context.getResources().getStringArray(R.array.page_titles_array);
return pageTitles[position];
}
@Override
public Fragment getItem(int position) {
SharedPreferences prefs = context.getSharedPreferences(Constants.SHARED_PREFS_FILE, 0);
long patientId = prefs.getLong(Constants.SELECTED_PATIENT_ID, 1);
Fragment fragment = null;
switch (position){
case 0:
return BMITabelleFragment.newInstance(patientId);
case 1:
return BMIChartFragment.newInstance(patientId);
default:
return BMITabelleFragment.newInstance(patientId);
}
}
@Override
public int getCount() {
return PAGE_COUNT;
}
}
这是fragment_bmitabs.xml：
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.TabLayout
android:id="@+id/sliding_tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabMode="scrollable" />
<android.support.v4.view.ViewPager
android:id="@+id/viewpager"
android:layout_width="match_parent"
android:layout_height="0px"
android:layout_weight="1"
android:background="@android:color/white" />
</LinearLayout>
我在这里缺少什么？
注意：我正在使用 AppCompatActivity 和支持库 v4 & v7 和 com:android:support:design 库