如何以编程方式“重新选择” TabLayout中的标签？

Question

TabLayout.OnTabSelectedListener has one callback which is onTabReselected(TabLayout.Tab tab)

We can reselect tab manually by tapping on selected tab again.

So my question is how to reselect tab programatically?

Answer 1

This is how I got my tabs working

Layout for tabs:

 <?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:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:background="#ffffff">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            app:layout_scrollFlags="scroll|enterAlways"
            app:layout_collapseMode="pin"
            android:background="#000000"
            app:titleTextColor="#ffffff"

            app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
            app:popupTheme="@style/PopupMenuStyle">

            <TextView
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:id="@+id/textview"
                android:textColor="@color/colorTrueWhite"/>

        </android.support.v7.widget.Toolbar>

        <!-- our tablayout to display tabs  -->
        <android.support.design.widget.TabLayout
            android:id="@+id/tabLayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@color/colorBlack"
            android:minHeight="?attr/actionBarSize"

            app:tabIndicatorColor="@color/colorTrueWhite"
            app:tabIndicatorHeight="5dp"
            android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"/>

        <!-- View pager to swipe views -->


        <android.support.v4.view.ViewPager
            android:id="@+id/pager"
            android:layout_width="match_parent"
            android:layout_height="fill_parent"/>


    </LinearLayout>

Activity using that layout:

public class Main2Activity extends AppCompatActivity implements TabLayout.OnTabSelectedListener {

    private TabLayout tabLayout;
    public static ViewPager viewPager;
    public static Context ctx;
    Pager adapter;
    public static int expired, paid;
    Boolean isConnection;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);

        Toolbar tb = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(tb);

        TextView tv = (TextView) findViewById(R.id.textview);

        //getSupportActionBar().setDisplayHomeAsUpEnabled(true);


        ctx = getApplicationContext();


        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);


        tabLayout = (TabLayout) findViewById(R.id.tabLayout);
        viewPager = (ViewPager) findViewById(R.id.pager);


        tabLayout.addTab(tabLayout.newTab().setText("title1"));
        tabLayout.addTab(tabLayout.newTab().setText("title2"));
        tabLayout.addTab(tabLayout.newTab().setText("title3"));
        tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
        tabLayout.setupWithViewPager(viewPager);

        adapter = new Pager(getSupportFragmentManager(), tabLayout.getTabCount(), ctx);
        viewPager.setAdapter(adapter);


        if(some condition)
        {
            viewPager.setCurrentItem(2);
        }
        else
        {
            viewPager.setCurrentItem(1);
        }
        viewPager.setOffscreenPageLimit(2);

        tabLayout.addOnTabSelectedListener(this);

        ViewGroup vg = (ViewGroup) tabLayout.getChildAt(0);
        int tabsCount = vg.getChildCount();
        for (int j = 0; j < tabsCount; j++) {
            ViewGroup vgTab = (ViewGroup) vg.getChildAt(j);
            int tabChildsCount = vgTab.getChildCount();
            for (int i = 0; i < tabChildsCount; i++) {
                View tabViewChild = vgTab.getChildAt(i);
                if (tabViewChild instanceof TextView) {
                    ((TextView) tabViewChild).setTypeface(Typeface.DEFAULT, Typeface.BOLD);
                }
            }
        }
    }


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

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

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


}

Pager code:

public class Pager extends FragmentStatePagerAdapter
{
    int tabcount;
    Context ctx;
    private String [] Titles = {"title1", "title2", "title3"};

    public Pager(FragmentManager fm, int tabcount, Context ctx)
    {
        super(fm);
        this.tabcount = tabcount;
        this.ctx = ctx;
    }

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

    @Override
    public CharSequence getPageTitle(int position) {
        return Titles[position];
    }

    @Override
    public Fragment getItem(int position) {

        switch (position) {

            case 0:
                Tab1 tab1 = new Tab1();
                return tab1;

            case 1:
                Tab2 tab2 = new Tab2();
                return tab2;

            case 2:
                Tab3 tab3 = new Tab3();
                return tab3;

            default:
                return null;
        }
    }


}