连续共享元素过渡

Question

我在android文档中看到了关于连续共享元素转换的代码行，如何将这些代码行复制到活动中。我了解共享转换的工作原理，但是在活动中实现的情况下，我不知道调用哪种方法。您可以获取完整的文档here

GridFragment转换为GridActivity

 setExitSharedElementCallback(
   new SharedElementCallback() {
     @Override
     public void onMapSharedElements(
         List<String> names, Map<String, View> sharedElements) {
       // Locate the ViewHolder for the clicked position.
       RecyclerView.ViewHolder selectedViewHolder = recyclerView
           .findViewHolderForAdapterPosition(MainActivity.currentPosition);
       if (selectedViewHolder == null || selectedViewHolder.itemView == null) {
         return;
       }

       // Map the first shared element name to the child ImageView.
       sharedElements
           .put(names.get(0),
                selectedViewHolder.itemView.findViewById(R.id.card_image));
     }
   });

ImagePagerFragment转换为ImagePagerActivity

  setEnterSharedElementCallback(
   new SharedElementCallback() {
     @Override
     public void onMapSharedElements(
         List<String> names, Map<String, View> sharedElements) {
          // Locate the image view at the primary fragment (the ImageFragment
          // that is currently visible). To locate the fragment, call
          // instantiateItem with the selection position.
          // At this stage, the method will simply return the fragment at the
          // position and will not create a new one.
       Fragment currentFragment = (Fragment) viewPager.getAdapter()
           .instantiateItem(viewPager, MainActivity.currentPosition);
       View view = currentFragment.getView();
       if (view == null) {
         return;
       }

       // Map the first shared element name to the child ImageView.
       sharedElements.put(names.get(0), view.findViewById(R.id.image));
     }
   });