AndyRoid AndyRoid - 6 months ago 22
Android Question

LinearLayoutManager setReverseLayout() == true but items stack from bottom

This seems like it would be an easy solution, but it seems that setting

private RecyclerView mRecyclerView;
private RecyclerView.Adapter mAdapter;
private LinearLayoutManager mLayoutManager;

.... // More code

mRecyclerView = (RecyclerView) rootView.findViewById(R.id.recycler_view);

// Add item decoration
mRecyclerView.addItemDecoration(new SpacesItemDecoration(DIVIDER_SPACE));

// use this setting to improve performance if you know that changes
// in content do not change the layout size of the RecyclerView
mRecyclerView.setHasFixedSize(true);

// use a linear layout manager
mLayoutManager = new LinearLayoutManager(getActivity());
mLayoutManager.setReverseLayout(true); // THIS ALSO SETS setStackFromBottom to true
mRecyclerView.setLayoutManager(mLayoutManager);


Seems to also set the items to stack from the bottom

I tried to set
setStackFromBottom
to false but that didn't do anything, what would be the best way to reverse the items order but still populate from the top? Should I use a Custom Comparator class instead? I was hoping this would be an easier process than creating another class.

Answer

from the docs for setReverseLayout

Used to reverse item traversal and layout order. This behaves similar to the layout change for RTL views. When set to true, first item is laid out at the end of the UI, second item is laid out before it etc. For horizontal layouts, it depends on the layout direction. When set to true, If RecyclerView is LTR, than it will layout from RTL, if RecyclerView} is RTL, it will layout from LTR. If you are looking for the exact same behavior of setStackFromBottom(boolean), use setStackFromEnd(boolean)

So, try also using setStackFromEnd(boolean) on your LinearLayoutManager instance,

mLayoutManager = new LinearLayoutManager(getActivity());
mLayoutManager.setReverseLayout(true);
mLayoutManager.setStackFromEnd(true);
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