This is an example of how it could have been done previously in the ListView class, using the divider and dividerHeight parameters:
<ListView android:id="@+id/activity_home_list_view" android:layout_width="match_parent" android:layout_height="match_parent" android:divider="@android:color/transparent" android:dividerHeight="8dp"/> However, I don't see such possibility in the RecyclerView class.
<android.support.v7.widget.RecyclerView android:id="@+id/activity_home_recycler_view" android:layout_width="match_parent" android:layout_height="match_parent" android:scrollbars="vertical"/> In that case, is it ok to define margins and/or add a custom divider view directly into a list item's layout or is there a better way to achieve my goal?
If you just want to add equal spacing and want to do it in XML, just set padding to your RecyclerView and equal amount of layoutMargin to the item you inflate into your RecyclerView , and let the background color determine the spacing color.
margin); int marginTopPx = (int) (marginTopDp * getResources(). getDisplayMetrics(). density + 0.5f); layoutParams. setMargins(0, marginTopPx, 0, 0); recyclerView.
Try to use cardElevation=0dp. This should remove the extra spacing between recyclerview items.
Add divider to your Recyclerview:ItemDecoration dividerItemDecoration = new DividerItemDecorator(ContextCompat. getDrawable(context, R. drawable. divider)); recyclerView.
October 2016 Update
The version 25.0.0 of Android Support Library introduced the DividerItemDecoration class:
DividerItemDecoration is a RecyclerView.ItemDecoration that can be used as a divider between items of a
LinearLayoutManager. It supports bothHORIZONTALandVERTICALorientations.
Usage:
DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(recyclerView.getContext(), layoutManager.getOrientation()); recyclerView.addItemDecoration(dividerItemDecoration); Previous answer
Some answers either use methods that have since become deprecated, or don't give a complete solution, so I tried to do a short, up-to-date wrap-up.
Unlike ListView, the RecyclerView class doesn't have any divider-related parameters. Instead, you need to extend ItemDecoration, a RecyclerView's inner class:
An
ItemDecorationallows the application to add a special drawing and layout offset to specific item views from the adapter's data set. This can be useful for drawing dividers between items, highlights, visual grouping boundaries and more.All
ItemDecorationsare drawn in the order they were added, before the item views (inonDraw()) and after the items (in onDrawOver(Canvas,RecyclerView,RecyclerView.State).
Vertical spacing ItemDecoration Extend ItemDecoration, add a custom constructor which takes space height as a parameter and override the getItemOffsets() method:
public class VerticalSpaceItemDecoration extends RecyclerView.ItemDecoration { private final int verticalSpaceHeight; public VerticalSpaceItemDecoration(int verticalSpaceHeight) { this.verticalSpaceHeight = verticalSpaceHeight; } @Override public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) { outRect.bottom = verticalSpaceHeight; } } If you don't want to insert space below the last item, add the following condition:
if (parent.getChildAdapterPosition(view) != parent.getAdapter().getItemCount() - 1) { outRect.bottom = verticalSpaceHeight; } Note: you can also modify outRect.top, outRect.left and outRect.right properties for the desired effect.
ItemDecoration Extend ItemDecoration and override the onDraw() method:
public class DividerItemDecoration extends RecyclerView.ItemDecoration { private static final int[] ATTRS = new int[]{android.R.attr.listDivider}; private Drawable divider; /** * Default divider will be used */ public DividerItemDecoration(Context context) { final TypedArray styledAttributes = context.obtainStyledAttributes(ATTRS); divider = styledAttributes.getDrawable(0); styledAttributes.recycle(); } /** * Custom divider will be used */ public DividerItemDecoration(Context context, int resId) { divider = ContextCompat.getDrawable(context, resId); } @Override public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) { int left = parent.getPaddingLeft(); int right = parent.getWidth() - parent.getPaddingRight(); int childCount = parent.getChildCount(); for (int i = 0; i < childCount; i++) { View child = parent.getChildAt(i); RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams(); int top = child.getBottom() + params.bottomMargin; int bottom = top + divider.getIntrinsicHeight(); divider.setBounds(left, top, right, bottom); divider.draw(c); } } } You can either call the first constructor that uses the default Android divider attributes, or the second one that uses your own drawable, for example drawable/divider.xml:
<?xml version="1.0" encoding="utf-8"?> <shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle"> <size android:height="1dp" /> <solid android:color="#ff992900" /> </shape> Note: if you want the divider to be drawn over your items, override the onDrawOver() method instead.
To use your new class, add VerticalSpaceItemDecoration or DividerSpaceItemDecoration to RecyclerView, for example in your fragment's onCreateView() method:
private static final int VERTICAL_ITEM_SPACE = 48; private RecyclerView recyclerView; private LinearLayoutManager linearLayoutManager; @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment_feed, container, false); recyclerView = (RecyclerView) rootView.findViewById(R.id.fragment_home_recycler_view); linearLayoutManager = new LinearLayoutManager(getActivity()); recyclerView.setLayoutManager(linearLayoutManager); //add ItemDecoration recyclerView.addItemDecoration(new VerticalSpaceItemDecoration(VERTICAL_ITEM_SPACE)); //or recyclerView.addItemDecoration(new DividerItemDecoration(getActivity())); //or recyclerView.addItemDecoration( new DividerItemDecoration(getActivity(), R.drawable.divider)); recyclerView.setAdapter(...); return rootView; } There's also Lucas Rocha's library which is supposed to simplify the item decoration process. I haven't tried it though.
Among its features are:
Just add
recyclerView.addItemDecoration(new DividerItemDecoration(getContext(), DividerItemDecoration.VERTICAL)); Also you may need to add the dependencyimplementation 'com.android.support:recyclerview-v7:28.0.0'
For customizing it a little bit you can add a custom drawable:
DividerItemDecoration itemDecorator = new DividerItemDecoration(getContext(), DividerItemDecoration.VERTICAL); itemDecorator.setDrawable(ContextCompat.getDrawable(getContext(), R.drawable.divider)); You are free to use any custom drawable, for instance:
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle"> <solid android:color="@color/colorPrimary"/> <size android:height="0.5dp"/> </shape>
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