I am trying to put a ViewPager2 with 2 tabs(2 fragments) within my main fragment.
My fragment class extends Fragment and I need it to contain a ViewPager2 with fragments implemented inside.
I couldn't find guides explaining this clearly on the web as all of them are being implemented within classes extending FragmentActivity and not Fragment.
For example: https://developer.android.com/training/animation/screen-slide-2#fragment
ViewPager2 is an improved version of the ViewPager library that offers enhanced functionality and addresses common difficulties with using ViewPager.
Such implementations for nesting a ViewPager2 within a fragment are missing on the web as Android Developer guide shows an implementation within activity.
1) Your main fragment layout must have a ViewPager2 added to its XML file as follows:
<com.google.android.material.tabs.TabLayout
android:id="@+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<!-- Tabs widget can be removed if you don't need tabs on top of pager-->
<androidx.viewpager2.widget.ViewPager2
android:id="@+id/myPager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="@+id/tabs" />
2) The next step is to prepare our FragmentStateAdapter to set it as the ViewPager2 adapter:
public class ViewPagerAdapter extends FragmentStateAdapter {
private final Fragment[] mFragments = new Fragment[] {//Initialize fragments views
//Fragment views are initialized like any other fragment (Extending Fragment)
new FirstPagerFrag(),//First fragment to be displayed within the pager tab number 1
new SecondPagerFrag(),
};
public final String[] mFragmentNames = new String[] {//Tabs names array
"First Tab",
"SecondTab"
};
public ViewPagerAdapter(FragmentActivity fa){//Pager constructor receives Activity instance
super(fa);
}
@Override
public int getItemCount() {
return mFragments.length;//Number of fragments displayed
}
@Override
public long getItemId(int position) {
return super.getItemId(position);
}
@NonNull
@Override
public Fragment createFragment(int position) {
return mFragments[position];
}
}
3) Attaching the adapter to ViewPager2 This part is implemented within our fragment that contains the ViewPager2:
private ViewPager2 mViewPager;
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mViewPager = view.findViewById(R.id.queueContainer);//Get ViewPager2 view
mViewPager.setAdapter(new ViewPagerAdapter(getActivity()));//Attach the adapter with our ViewPagerAdapter passing the host activity
TabLayout tabLayout = view.findViewById(R.id.tabs);
new TabLayoutMediator(tabLayout, mViewPager,
new TabLayoutMediator.TabConfigurationStrategy() {
@Override
public void onConfigureTab(@NonNull TabLayout.Tab tab, int position) {
tab.setText(((ViewPagerAdapter)(mViewPager.getAdapter())).mFragmentNames[position]);//Sets tabs names as mentioned in ViewPagerAdapter fragmentNames array, this can be implemented in many different ways.
}
}
).attach();
}