implementation of viewPager2

Question

我实现了viewPager，它工作得很好，但现在我想移动到viewPager2，但我不知道写什么而不是addOnPageChangeListener，因为我有一个错误，在viewPager2中没有这样的功能。这是我的主要活动代码:

package com.example.viewpager;
import androidx.appcompat.app.AppCompatActivity;
import android.net.Uri;
import android.os.Bundle;
import androidx.viewpager2.widget.ViewPager2;
import com.google.android.material.tabs.TabLayout;
public class MainActivity extends AppCompatActivity implements 
Tab1.OnFragmentInteractionListener, Tab2.OnFragmentInteractionListener, 
Tab3.OnFragmentInteractionListener{
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TabLayout tabLayout = (TabLayout) 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"));
tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
final ViewPager2 viewPager = (ViewPager2) findViewById(R.id.pager);
final PagerAdapter adapter = new PagerAdapter(getSupportFragmentManager(), getLifecycle());
viewPager.setAdapter(adapter);
//        viewPager.setOffscreenPageLimit(2);
// new ViewPager2.OnPageChangeCallback(new 
TabLayout.TabLayoutOnPageChangeListener(tabLayout));
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.addOnTabSelectedListener(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) {
}
});
}
@Override
public void onFragmentInteraction(Uri uri){
}

}

Answer 1

是的，这个链接有帮助。我更改了这些代码行:

tabLayout.addOnTabSelectedListener(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) {
}
});
viewPager.registerOnPageChangeCallback(new ViewPager2.OnPageChangeCallback() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
super.onPageScrolled(position, positionOffset, positionOffsetPixels);
tabLayout.selectTab(tabLayout.getTabAt(position));
}
});