Android TV Leanback RowsFragment keep focused item at the start

Question

I'm working on a Leanback app and I've implemented the rows and everything via RowsFragment and its all working great.

As for now when I go left and right within the items in the row the focused item moves to the middle of the screen and gains the focus.

Example -

I want the focused item to stay at the beginning of the row and not at the middle.

Example -

Couldn't find anything on this on the web. Would really appreciate any information regarding this.

Answer 1

If you also want the last item of the row to appear at the beginning, use this ListRowPresenter:

class FocusedItemAtStartListRowPresenter(focusZoomFactor: Int) : ListRowPresenter(focusZoomFactor) {
    override fun createRowViewHolder(parent: ViewGroup): RowPresenter.ViewHolder {
        val viewHolder = super.createRowViewHolder(parent)

        with((viewHolder.view as ListRowView).gridView) {
            windowAlignment = BaseGridView.WINDOW_ALIGN_LOW_EDGE
            windowAlignmentOffsetPercent = 0f
            windowAlignmentOffset = parent.resources.getDimensionPixelSize(R.dimen.lb_browse_padding_start)
            itemAlignmentOffsetPercent = 0f
        }

        return viewHolder
    }
}

This is similar to what the Leanback Launcher does.

Answer 2

Faced the same issue and solved it by using a custom ListRowPresenter:

override fun createRowViewHolder(parent: ViewGroup): RowPresenter.ViewHolder {
        val viewHolder = super.createRowViewHolder(parent)

        val itemWidth = parent.resources.getDimensionPixelSize(R.dimen.epg_program_width)

        with((viewHolder as ListRowPresenter.ViewHolder).gridView) {
            itemAlignmentOffset = parent.width / 2 - itemWidth / 2 - paddingLeft
        }

        return viewHolder
    }

Answer 3

To be complete as tvlauncher you need also set this:

fadingLeftEdge = true // to fade previous item out

But better is to use their FadingEdgeContainer, as fading edge is not really the same.

Something like this: https://github.com/bosphere/Android-FadingEdgeLayout