Android使用Recyclerview实现图片水平自动循环滚动效果

简介：

本篇博客主要介绍的是如何使用RecyclerView实现图片水平方向自动循环（跑马灯效果）

效果图： 　　

思路：

1.准备m张图片

1.使用Recyclerview实现，返回无数个（实际Interge.MAXVALUE）item，第n个item显示第n%m张图片

3.使用recyclerview.scrollBy  每个一段时间水平滚动一段距离

4.通过layoutManager.findFirstVisibleItemPosition()获取当前显示的第一个View是第几个item,上面的ImageView显示对应de图片

实现代码：

XML文件

1.activity布局文件activity_recy.xml　　

2.适配器布局item_horizon.xml　　

Activity　　

public class HorizontalActivity extends AppCompatActivity implements RecyAdapter.OnItemClickListener {
  private String TAG="HorizontalActivity";

  @BindView(R.id.img)
  ImageView img;
  @BindView(R.id.recyclerview)
  RecyclerView recyclerview;


  private Integer[] mImgIds = {R.drawable.p1,R.drawable.p2,R.drawable.p3,R.drawable.p4,R.drawable.p5,R.drawable.pic1,R.drawable.pic5,R.drawable.pic6};
  private List datas;
  private RecyAdapter recyAdapter;
  private Handler mHandler=new Handler();
  private LinearLayoutManager layoutManager;

  private int oldItem=0;


  @Override
  protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_recy);
    ButterKnife.bind(this);
    initData();
    initRecy();
    img.setImageResource(datas.get(0));
    recyAdapter.setOnItemClickListener(this);
  }


  Runnable scrollRunnable=new Runnable() {
    @Override
    public void run() {
      recyclerview.scrollBy(3,0);

//      int firstItem = layoutManager.findFirstVisibleItemPosition();
      int firstItem=layoutManager.findFirstVisibleItemPosition();
      if(firstItem!=oldItem&&firstItem>0){
        oldItem=firstItem;
        img.setImageResource(datas.get(oldItem%datas.size()));
      }

      Log.e(TAG,"run: firstItem:"+firstItem );


      mHandler.postDelayed(scrollRunnable,10);
    }
  };

  private void initRecy() {
    recyAdapter=new RecyAdapter(this,datas);

    layoutManager = new LinearLayoutManager(this);
    layoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
    recyclerview.setLayoutManager(layoutManager);
    recyclerview.setAdapter(recyAdapter);
  }

  private void initData() {
    datas=new ArrayList<>();
    for (int i = 0; i 

适配器RecyAdapter



public class RecyAdapter extends RecyclerView.Adapter implements View.OnClickListener {

  private Context context;
  private List datas;
  private OnItemClickListener onItemClickListener;

  public RecyAdapter(Context context,List datas) {
    this.context = context;
    this.datas = datas;
  }

  @Override
  public ViewHolder onCreateViewHolder(ViewGroup parent,int viewType) {
    View view = LayoutInflater.from(context).inflate(R.layout.item_horizontal,parent,false);
    ViewHolder vh=new ViewHolder(view);
    view.setOnClickListener(this);
    return vh;
  }


  @Override
  public void onBindViewHolder(ViewHolder holder,int position) {
    int newPos=position%datas.size();

    holder.img.setImageResource(datas.get(newPos));

    holder.itemView.setTag(position);


  }

  @Override
  public int getItemCount() {
    return Integer.MAX_VALUE;
  }

  @Override
  public void onClick(View view) {
    if(onItemClickListener!=null){
      onItemClickListener.onItemClick(view,(Integer) view.getTag());
    }
  }


  class ViewHolder extends RecyclerView.ViewHolder {
     ImageView img;
    public ViewHolder(View itemView) {
      super(itemView);
      img=itemView.findViewById(R.id.img);
    }
  }

  public void setOnItemClickListener(OnItemClickListener listener){
    this.onItemClickListener=listener;

  }
  interface OnItemClickListener{
    void onItemClick(View view,int tag);
  }

}