Android Studio CardView with two columns that have equal width

Question

I am trying to display in a cardview two elements on each row ( two columns ). However, they are not centered in the cardview. click here to see how the cardview displays items

Here is the code in the xml.:

 <androidx.recyclerview.widget.RecyclerView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="#FFDB78"
            android:layout_below="@+id/LinearLayoutCateg"
            android:layout_above="@+id/menu"
            android:id="@+id/currentCategoryRecyclerView"/>

I create a new GridLayoutManager in the Main activity, programatically, like this:

 recyclerView.setLayoutManager(new GridLayoutManager(CategoryListActivity.this,2));
        recyclerView.setAdapter(categoryRecycler);

The cardview is in a Relative Layout that has the "android:gravity="center" property, if that matters. I am not sure what I am missing.

Answer 1

I have the same problem as you, I found the RecyclerView.ItemDecoration class for RecyclerView Spacing.

public class ItemOffsetDecoration extends RecyclerView.ItemDecoration {

private int mItemOffset;

public ItemOffsetDecoration(int itemOffset) {
    mItemOffset = itemOffset;
}

public ItemOffsetDecoration(@NonNull Context context, @DimenRes int itemOffsetId) {
    this(context.getResources().getDimensionPixelSize(itemOffsetId));
}

@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
        RecyclerView.State state) {
    super.getItemOffsets(outRect, view, parent, state);
    outRect.set(mItemOffset, mItemOffset, mItemOffset, mItemOffset);
}

}

Add ItemOffsetDecoration to your RecyclerView.
Item offset value should be half size of the actual value you want to add a space between items.

 mRecyclerView.setLayoutManager(new GridLayoutManager(context, NUM_COLUMNS);
ItemOffsetDecoration itemDecoration = new ItemOffsetDecoration(context, R.dimen.item_offset);
mRecyclerView.addItemDecoration(itemDecoration);

Also, set item offset value as padding for its RecyclerView, and specify android:clipToPadding=false.

<android.support.v7.widget.RecyclerView
android:id="@+id/recyclerview_grid"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clipToPadding="false"
android:padding="@dimen/item_offset"/>    <!--Give a desired size-->

refer