TabLayout选项卡文本不显示 [英] TabLayout tabs text not displaying

问题描述

我正在Fragment内使用TabLayout来显示三个固定的选项卡，并且这些选项卡正在工作，但是即使在布局中设置了app:tabTextColor属性后，该选项卡也不显示选项卡文本，但该属性仍然不可见.

I am using TabLayout inside a Fragment to display three fixed tabs and the tabs are working but it doesn't show the tab text even after I set the app:tabTextColor attribute in the layout it's still not visible.

NewFragment.java

public class NewFragment extends Fragment {

private RecyclerView mRecyclerView;
private RecyclerView.LayoutManager mLayoutManager;
private RecyclerView.Adapter mAdapter;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    View inflatedView = inflater.inflate(R.layout.new_fragment, container, false);

    TabLayout tabLayout = (TabLayout) inflatedView.findViewById(R.id.tabLayout);
    tabLayout.addTab(tabLayout.newTab().setText("Tab 1"));
    tabLayout.addTab(tabLayout.newTab().setText("Tab 2"));
    tabLayout.addTab(tabLayout.newTab().setText("Tab 3"));
    final ViewPager viewPager = (ViewPager) inflatedView.findViewById(R.id.viewpager);

    LinearLayoutManager mLayoutManager = new LinearLayoutManager(getActivity());
    mLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);

    viewPager.setAdapter(new PagerAdapter(getFragmentManager(), tabLayout.getTabCount()));
    viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
    tabLayout.setupWithViewPager(viewPager);
    tabLayout.setTabMode(TabLayout.MODE_FIXED);
    tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {

        @Override
        public void onTabSelected(TabLayout.Tab tab) {
            viewPager.setCurrentItem(tab.getPosition());
        }

        @Override
        public void onTabUnselected(TabLayout.Tab tab) {

        }

        @Override
        public void onTabReselected(TabLayout.Tab tab) {

        }
    });

    return inflatedView;
}

public class PagerAdapter extends FragmentStatePagerAdapter {
    int mNumOfTabs;

    public PagerAdapter(FragmentManager fm, int NumOfTabs) {
        super(fm);
        this.mNumOfTabs = NumOfTabs;
    }

    @Override
    public Fragment getItem(int position) {

        switch (position) {
            case 0:
                return new FragmentTab();
            case 1:
                return new FragmentTab();
            case 2:
                return new FragmentTab();
            default:
                return null;
        }
    }

    @Override
    public int getCount() {
        return mNumOfTabs;
    }
}
}

newfragment.xml

<android.support.design.widget.AppBarLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context=".NewFragment">

<android.support.design.widget.TabLayout
    android:id="@+id/tabLayout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:tabMode="fixed"
    app:tabTextColor="#ffffff"
    app:tabGravity="fill"
    app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"/>

<android.support.v4.view.ViewPager
    android:id="@+id/viewpager"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@android:color/white"/>

</android.support.design.widget.AppBarLayout>

推荐答案

问题是您在使用addTab()调用设置了选项卡之后，正在调用setupWithViewPager()，有效地覆盖了它们.

The problem is you're calling setupWithViewPager() after setting up your tabs with the addTab() calls, effectively overwriting them.

来自setupWithViewPager()的TabLayout的noreferrer>文档:

From the documentation of TabLayout regarding setupWithViewPager():

在此显示的选项卡 布局将从ViewPager适配器的页面标题填充.

The tabs displayed in this layout will be populated from the ViewPager adapter's page titles.

如果要将TabLayout与ViewPager一起使用，则应在PagerAdapter中覆盖getPageTitle()(并删除addTab()调用，它们是多余的).

If you would like to use your TabLayout with a ViewPager, you should override getPageTitle() in your PagerAdapter (and remove the addTab() calls, they are redundant).

例如:

public class ExamplePagerAdapter extends FragmentStatePagerAdapter {

    // tab titles
    private String[] tabTitles = new String[]{"Tab1", "Tab2", "Tab3"};

    public ExamplePagerAdapter(FragmentManager fm) {
        super(fm);
    }

    // overriding getPageTitle()
    @Override
    public CharSequence getPageTitle(int position) {
        return tabTitles[position];
    }

    @Override
    public Fragment getItem(int position) {
        switch (position) {
            case 0:
                return new Tab1Fragment();
            case 1:
                return new Tab2Fragment();
            case 2:
                return new Tab3Fragment();
            default:
                throw new RuntimeException("Invalid tab position");
        }
    }

    @Override
    public int getCount() {
        return tabTitles.length;
    }

    // ...
}

这篇关于TabLayout选项卡文本不显示的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！