Android使用Recyclerview实现图片轮播效果的方法

发布时间：2020-06-23 15:47:58

来源：亿速云

阅读：113

作者：清晨

这篇文章将为大家详细讲解有关Android使用Recyclerview实现图片轮播效果的方法，小编觉得挺实用的，因此分享给大家做个参考，希望大家阅读完这篇文章后可以有所收获。

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

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical">

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:layout_width="match_parent"

android:layout_height="150dp"

android:layout_marginTop="10dp"

android:id="@+id/recyclerview"

>

2.适配器布局item_horizon.xml

android:layout_width="wrap_content"

android:layout_height="match_parent"

android:orientation="vertical"

>

android:layout_width="100dp"

android:layout_height="match_parent"

android:id="@+id/img"

android:layout_marginLeft="5dp"

android:layout_marginRight="5dp"

android:scaleType="fitXY"

/>

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

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 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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