使用ViewPager2在TabLayout中预先选择选项卡

import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentActivity;
import androidx.viewpager2.adapter.FragmentStateAdapter;
import com.google.android.material.tabs.TabLayout;
import com.google.android.material.tabs.TabLayoutMediator;

public class MainActivity extends AppCompatActivity {

    private ViewPager2 viewPager;
    private TabLayout tabLayout;

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

        viewPager = findViewById(R.id.viewPager);
        tabLayout = findViewById(R.id.tabLayout);

        viewPager.setAdapter(new MyAdapter(this));

        new TabLayoutMediator(tabLayout, viewPager, (tab, position) -> tab.setText("Tab " + (position + 1))).attach();

        // 预先选择第二个选项卡
        viewPager.setCurrentItem(1, false);
    }

    public static class MyAdapter extends FragmentStateAdapter {

        public MyAdapter(@NonNull FragmentActivity fragmentActivity) {
            super(fragmentActivity);
        }

        @NonNull
        @Override
        public Fragment createFragment(int position) {
            return new MyFragment();
        }

        @Override
        public int getItemCount() {
            return 3;
        }
    }

    public static class MyFragment extends Fragment {
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            return inflater.inflate(R.layout.fragment_my, container, false);
        }
    }
}