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　　

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <ImageView android:layout_width="300dp" android:layout_height="350dp" android:layout_gravity="center_horizontal" android:id="@+id/img" android:src="@drawable/p5" android:scaleType="fitXY" /> <android.support.v7.widget.RecyclerView android:layout_width="match_parent" android:layout_height="150dp" android:layout_marginTop="10dp" android:id="@+id/recyclerview" ></android.support.v7.widget.RecyclerView></LinearLayout>

2.适配器布局item_horizon.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="wrap_content" android:layout_height="match_parent" android:orientation="vertical" > <ImageView android:layout_width="100dp" android:layout_height="match_parent" android:id="@+id/img" android:layout_marginLeft="5dp" android:layout_marginRight="5dp" android:scaleType="fitXY" /></LinearLayout>

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<Integer> 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 <mImgIds.length ; i++) { datas.add(mImgIds[i]); } } @Override protected void onResume() { super.onResume(); mHandler.postDelayed(scrollRunnable,10); } @Override protected void onStop() { super.onStop(); mHandler.removeCallbacks(scrollRunnable); } @Override public void onItemClick(View view, int tag) { Toast.makeText(this,"第"+tag+"张图片被点击了",Toast.LENGTH_SHORT).show(); }}

适配器RecyAdapter

public class RecyAdapter extends RecyclerView.Adapter<RecyAdapter.ViewHolder> implements View.OnClickListener { private Context context; private List<Integer> datas; private OnItemClickListener onItemClickListener; public RecyAdapter(Context context, List<Integer> 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); }}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。