Recyclerview水平甲板卡片作用

Question

我正在尝试制作简单的纸牌游戏，我需要在桌面上显示卡片水平，用户可以通过点击选择任意数量的卡片。理想情况下，当使用任何卡片时，卡片应该从其他卡片上提升一点。加卡并非完全可见，它们部分可见，如this。我创建了自定义Recyclerview并使用了项目装饰器来更改卡片的偏移量。然而，每当我改变偏移时，甲板的第一张或最后一张卡完全与其他卡重叠。如下图所示，

如何正确显示上述效果，不丢失第一张（或最后一张）卡？当我们点击它们时，如何实现任何这些卡的提升？我尝试使用＆＃34; setElevation（）＆＃34;但它没有效果。如果我能够在没有任何第三方库的情况下实现，那将是很好的（但我愿意接受建议）。我使用了以下代码，

Game.java

public class Game extends AppCompatActivity {

    private List<Card> cards = new ArrayList<>();
    private RecyclerView.ItemDecoration decoration = new OverlapDecoration();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.game);
        RecyclerView marketDeck = (RecyclerView) findViewById(R.id.market_deck);


        Card item1 = new Card();
        item1.setImage(R.color.colorPrimary);
        Card item2 = new Card();
        item2.setImage(R.color.colorAccent);

        cards.add(item1);
        cards.add(item2);
        cards.add(item1);
        cards.add(item2);
        cards.add(item1);

        CardHolder cardHolder = new CardHolder(cards);
        marketDeck.setAdapter(cardHolder);
        marketDeck.setLayoutManager(new LinearLayoutManager(getBaseContext(), LinearLayoutManager.HORIZONTAL, false));
        marketDeck.addItemDecoration(decoration);

        cardHolder.setOnCardClick(new CardHolder.onCardClick() {
            @Override
            public void onClick(View v) {
                v.setElevation(10);
            }
        });


    }

    private class OverlapDecoration extends RecyclerView.ItemDecoration {

        //Following code from : http://stackoverflow.com/questions/27633454/how-to-overlap-items-in-linearlayoutmanager-recyclerview-like-stacking-cards
        private final static int overlap = -100;

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

            final int itemPosition = parent.getChildAdapterPosition(view);
            if (itemPosition == RecyclerView.NO_POSITION) {
                return;
            }
            outRect.set(overlap, 0, 0, 0);
        }
    }

}

CardHolder.java

public class CardHolder extends RecyclerView.Adapter<CardHolder.CardView> {

    private List<Card> cards;

    private onCardClick cardClick;

    public CardHolder(List<Card> cards) {
        this.cards = cards;
    }

    @Override
    public CardView onCreateViewHolder(ViewGroup parent, int viewType) {
        return new CardView(LayoutInflater.from(parent.getContext()).inflate(R.layout.card, parent, false));
    }

    @Override
    public void onBindViewHolder(CardView holder, int position) {
        Card card = cards.get(position);
        holder.icon.setImageResource(card.getImage());

    }

    @Override
    public int getItemCount() {
        return cards.size();
    }

    class CardView extends RecyclerView.ViewHolder {
        ImageView icon;

        CardView(final View itemView) {
            super(itemView);
            icon = (ImageView) itemView.findViewById(R.id.card_icon);
            icon.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    cardClick.onClick(v);
                }
            });
        }
    }

    void setOnCardClick(onCardClick click) {
        cardClick = click;
    }

    public interface onCardClick {
        void onClick(View v);
    }


}

Card.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:padding="5sp">

    <ImageView
        android:id="@+id/card_icon"
        style="@style/CardTheme"
        android:contentDescription="@null"
        app:srcCompat="@color/colorPrimary" />
</LinearLayout>

game.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.company.someapp.Game">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/market_deck"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>

注意：我保持recyclerview的宽度是＆＃34; wrap_content＆＃34;因为卡的数量是可变的。

Answer 1

通过调整第一个元素的边距来实现它，如下所示，

private class OverlapDecoration extends RecyclerView.ItemDecoration {

        //Following code from : http://stackoverflow.com/questions/27633454/how-to-overlap-items-in-linearlayoutmanager-recyclerview-like-stacking-cards
        private final static int overlap = -100;

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

             final int itemPosition = parent.getChildAdapterPosition(view);
        if (itemPosition == 0) {
            outRect.set(0, 0, 0, 0);
        } else {
            outRect.set(overlap, 0, 0, 0);
        }
        }
    }