开始时选择Android Design支持库选项卡

我正在使用Android Design支持库在我的包含3个标签的应用中实现滑动标签功能.我想知道将中间选项卡设置为在应用程序启动时显示的选项卡需要做什么.

public class TabFragmentContainer extends Fragment {

    // Create the FragmentPagerAdapter that will provide and manage tabs for each section.
    public static MyFragmentPagerAdapter myFragmentPagerAdapter;

    public static TabLayout tabLayout;

    // The ViewPager is a layout widget in which each child view is a separate tab in the layout.
    // It will host the section contents.
    public static ViewPager viewPager;

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

        // Inflate tab_layout_fragment_container view and setup views for the TabLayout and ViewPager items.
        View view = inflater.inflate(R.layout.tab_layout_fragment_container, null);

        tabLayout = (TabLayout) view.findViewById(R.id.tabs);

        // Set up the ViewPager with the sections adapter.
        viewPager = (ViewPager) view.findViewById(R.id.viewpager);

        // Instantiate the adapter that will return a fragment for each of the three sections of the main activity
        myFragmentPagerAdapter = new MyFragmentPagerAdapter(getActivity(), getChildFragmentManager());

        // Set up the adapter for the ViewPager
        viewPager.setAdapter(myFragmentPagerAdapter);

        // Runnable() method required to implement setupWithViewPager() method
        tabLayout.post(new Runnable() {
            @Override
            public void run() {
                tabLayout.setupWithViewPager(viewPager);
            }
        });

        // Return the created View
        return view;
    }

}





public class MyFragmentPagerAdapter extends FragmentPagerAdapter {

    // The context to be passed in when the adapter is created.
    private Context mContext;
    // The number of tabs in the layout.
    public static int numberOfTabs = 3;

    /**
     * Default constructor that accepts a FragmentManager parameter to add or remove fragments.
     *
     * @param context         the context from the activity using the adapter.
     * @param fragmentManager the FragmentManager for managing Fragments inside of the TabFragmentContainer.
     */
    public MyFragmentPagerAdapter(Context context, FragmentManager fragmentManager) {
        super(fragmentManager);
        mContext = context;
    }

    /**
     * Method to return the relevant fragment for the selected tab.
     */
    @Override
    public Fragment getItem(int position) {
        switch (position) {
            case 0:
                return new SettingsFragment();
            case 1:
                return new InboxRouteFragment();
            case 2:
                return new FriendsFragment();
        }
        return null;
    }

    /**
     * Method that gets the number of tabs in the layout.
     *
     * @return the number of tabs in the layout.
     */
    @Override
    public int getCount() {
        return numberOfTabs;
    }

    /**
     * Method that returns the title of each tab in the layout.
     */
    @Override
    public CharSequence getPageTitle(int position) {
        Locale locale = Locale.getDefault();
        switch (position) {
            case 0:
                return mContext.getString(R.string.title_section1).toUpperCase(locale);
            case 1:
                return mContext.getString(R.string.title_section2).toUpperCase(locale);
            case 2:
                return mContext.getString(R.string.title_section3).toUpperCase(locale);
        }
        return null;
    }
}

解决方法:

尝试使用：viewPager.setCurrentItem(1,false)

标签：android-tablayout,android-design-library,android,android-tabs,androiddesignsuppo
来源： https://codeday.me/bug/20191119/2038877.html