RecyclerView show many items and make current item in center - android-recyclerview

Question

Like this.
Show three items at screen, but left and right item show only edge
When index = 0, show first item at center
When index = n, show current item at center
|-----------------------------------|
| |
| |
| |---------------| |----|
| | | | |
| | | | |
| | | | |
| | | | |
| | 1 | | 2 |
| | | | |
| | | | |
| | | | |
| | | | |
| |---------------| |----|
| |
| |
|-----------------------------------|
|-----------------------------------|
| |
| |
|----| |---------------| |----|
| | | | | |
| | | | | |
| | | | | |
| | | | | |
| 1 | | 2 | | 3 |
| | | | | |
| | | | | |
| | | | | |
| | | | | |
|----| |---------------| |----|
| |
| |
|-----------------------------------|
I have try SnapHelper, but I don't known how

Answer 1

Take LinearLayout in your RecyclerView's item row layout then give android:layout_gravity="center" to LinearLayout.

Answer 2

Basically there are two layout files which are required to be created, one is activity_main.xml and another one is the layout that shows each item in the RecyclerView. Consider the name of the layout file to be layout_r.xml.
activity_main.xml
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal">
<RecyclerView
android:id="#+id/recyclerView"
android:layout_width="match_parent" <!--This can be changed to wrap_content or match_parent, even though match_parent makes single view on the screen-->
android:layout_height="wrap_content">
</RecyclerView>
</LinearLayout>
layout_r.xml
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<TextView
android:id="#+id/tvText"
android:text="Add text here"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
<!--............And rest of the views..............-->
</LinearLayout>

Answer 3

In order to center the first and the last items, you need to create extra space at the beginning and end of your RecyclerView. An easy way to do so is to use an ItemDecoration, like so:
class BoundsOffsetDecoration : ItemDecoration() {
override fun getItemOffsets(outRect: Rect,
view: View,
parent: RecyclerView,
state: RecyclerView.State) {
super.getItemOffsets(outRect, view, parent, state)
val itemPosition = parent.getChildAdapterPosition(view)
// It is crucial to refer to layoutParams.width (view.width is 0 at this time)!
val itemWidth = view.layoutParams.width
val offset = (parent.width - itemWidth) / 2
if (itemPosition == 0) {
outRect.left = offset
} else if (itemPosition == state.itemCount - 1) {
outRect.right = offset
}
}
}
And for the "center" effect you should use a PagerSnapHelper:
PagerSnapHelper().attachToRecyclerView(recyclerView)
I've written a Medium post describing a step-by-step implementation of this kind of carousels using RecyclerView and SnapHelper, if you need more details.