我正试图在我的主片段中放置一个带有2个选项卡(即2个片段)的ViewPager2。
我的片段类扩展了Fragment,我需要它包含一个已内部实现的ViewPager2片段。
我无法找到明确解释如何实现此操作的指南,因为所有这些指南都是在扩展FragmentActivity而不是Fragment的类中实现的。
例如:https://developer.android.com/training/animation/screen-slide-2#fragment
我正试图在我的主片段中放置一个带有2个选项卡(即2个片段)的ViewPager2。
我的片段类扩展了Fragment,我需要它包含一个已内部实现的ViewPager2片段。
我无法找到明确解释如何实现此操作的指南,因为所有这些指南都是在扩展FragmentActivity而不是Fragment的类中实现的。
例如:https://developer.android.com/training/animation/screen-slide-2#fragment
<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) 下一步是准备我们的FragmentStateAdapter,并将其设置为ViewPager2的适配器:
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) 将适配器附加到ViewPager2 这一部分是在包含ViewPager2的片段中实现的:
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();
}
private final Map<Integer, Fragment> fragmentMap;
@NonNull @Override public Fragment createFragment(int position) {
Fragment cachedFragment = fragmentMap.get(position);
if (cachedFragment != null) {
return cachedFragment;
}
switch (position) {
case 0:
cachedFragment = new childfragment1();
break;
case 1:
cachedFragment = new childfragment2();
break;
case 2:
cachedFragment = new childfragment3();
break;
default:
cachedFragment = null;
}
fragmentMap.put(position, cachedFragment);
return cachedFragment;
}