Recyclerview滑动点击居中

最新推荐文章于 2024-12-09 19:10:31 发布

原创最新推荐文章于 2024-12-09 19:10:31 发布 · 861 阅读

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本文介绍了一个自定义的RecyclerView居中布局管理器CenterLayoutManager，并实现了一个ListHeadAdapter适配器，该适配器能够根据列表项数量调整布局并支持点击事件。

headList是Recyclerview
listHeadAdapter 是适配器
centerLayoutManager 是居中的管理

headList.setVisibility(View.VISIBLE);
listHeadAdapter = new ListHeadAdapter(getActivity(), children);
CenterLayoutManager centerLayoutManager = new CenterLayoutManager(getContext(), RecyclerView.HORIZONTAL, false);
headList.setAdapter(listHeadAdapter);
if (children.size() <= 4) {
    headList.setLayoutManager(new GridLayoutManager(getContext(), children.size()));
    RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,120);
    layoutParams.setMargins(30,16,30,0);
    headList.setLayoutParams(layoutParams);
} else {
    headList.setLayoutManager(centerLayoutManager);
    RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,120);
    layoutParams.setMargins(30,16,0,0);
    headList.setLayoutParams(layoutParams);
}

listHeadAdapter.setOnItemClickLitener(new ListHeadAdapter.OnItemClickLitener() {
    @Override
    public void onItemClick(View view, int position) {
        mChildren = children.get(position);
        listHeadAdapter.setThisPosition(position);
        commonNewsAdapter.getLoadMoreModule().setEnableLoadMore(false);
        page = 1;
        lastTime = 0;
        loadNetData();
        refreshLayout.finishRefresh();
        if (children.size() > 4) {
            headList.smoothScrollToPosition(position);//加个这个，让Recyclerview可以滑动更多
            centerLayoutManager.smoothScrollToPosition(headList, new RecyclerView.State(), position);
        }
    }
});

ListHeadAdapter是点击变颜色等适配用

public class ListHeadAdapter extends RecyclerView.Adapter<ListHeadAdapter.MyViewHolder>{
    List<ChildrenDate> list;
    Context context;
    //先声明一个int成员变量,若为0默认显示第一个
    private int thisPosition = 0;
    GradientDrawable read_stroke,gray_stroke;
    //再定义一个int类型的返回值方法
    public int getthisPosition() {
        return thisPosition;
    }
    //   传入点击的位置
    public void setThisPosition(int thisPosition) {
        this.thisPosition = thisPosition;
        notifyDataSetChanged();
    }
    public ListHeadAdapter(Context context, List<ChildrenDate> list) {
        this.context = context;
        this.list = list;
        read_stroke = new GradientDrawable();
        read_stroke.setCornerRadius(15);
        read_stroke.setColor(context.getResources().getColor(R.color.primary));
        gray_stroke = new GradientDrawable();
        gray_stroke.setCornerRadius(15);
        gray_stroke.setColor(Color.parseColor("#F3F3F3"));
    }

    public interface OnItemClickLitener{
        void onItemClick(View view, int position);
    }
    private ListHeadAdapter.OnItemClickLitener mOnItemClickLitener;

    public void setOnItemClickLitener(ListHeadAdapter.OnItemClickLitener mOnItemClickLitener)
    {
        this.mOnItemClickLitener = mOnItemClickLitener;
    }

    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(context).inflate(R.layout.topheadlist_item_layout, parent, false);
        MyViewHolder holder = new MyViewHolder(view);
        return holder;
    }

    @Override
    public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {
        if(position==getthisPosition()){
            holder.textView.setBackground(read_stroke);
            holder.textView.setTextColor(Color.WHITE);
        }else {
            holder.textView.setBackground(gray_stroke);
            holder.textView.setTextColor(context.getResources().getColor(R.color.black_999));
        }
        if(list.size()>4){
            int width = (ScreenUtils.getScreenWidth(context)-100)/4;
            LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(width,97);
            holder.layout.setLayoutParams(layoutParams);
        }else {
            int width = (ScreenUtils.getScreenWidth(context)-60)/list.size();
            LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(width,97);
            holder.layout.setLayoutParams(layoutParams);
        }

        holder.textView.setText(list.get(position).getCatename());
        holder.itemView.setOnClickListener(new NoDoubleClickListener() {
            @Override
            protected void onNoDoubleClick(View v) {
                int pos = holder.getLayoutPosition();
                mOnItemClickLitener.onItemClick(holder.textView,pos);
            }
        });
    }

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

    class MyViewHolder extends RecyclerView.ViewHolder {

        TextView textView;
        LinearLayout layout;
        public MyViewHolder(View view) {
            super(view);
            textView = view.findViewById(R.id.tophead_item_text);
            SDTypeFaces.setTitleTypeface(textView);
            layout = view.findViewById(R.id.tophead_item_layout);
        }
    }

}

CenterLayoutManager网上能找到

public class CenterLayoutManager extends LinearLayoutManager {
    public CenterLayoutManager(Context context) {
        super(context);
    }

    public CenterLayoutManager(Context context, int orientation, boolean reverseLayout) {
        super(context, orientation, reverseLayout);
    }

    public CenterLayoutManager(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    @Override
    public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state, int position) {
        RecyclerView.SmoothScroller smoothScroller = new CenterSmoothScroller(recyclerView.getContext());
        smoothScroller.setTargetPosition(position);
        startSmoothScroll(smoothScroller);
    }

    private static class CenterSmoothScroller extends LinearSmoothScroller {

        CenterSmoothScroller(Context context) {
            super(context);
        }

        @Override
        public int calculateDtToFit(int viewStart, int viewEnd, int boxStart, int boxEnd, int snapPreference) {
            int start = (boxStart + (boxEnd - boxStart) / 2) - (viewStart + (viewEnd - viewStart) / 2);
            return start;
        }

        @Override
        protected float calculateSpeedPerPixel(DisplayMetrics displayMetrics) {
            return 100f / displayMetrics.densityDpi;
        }
    }

}

具体效果可以自己试一下