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);
 }

}


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