Android ListView实现无限循环滚动

Z时代
2024-01-10
分类：IT

本文实例为大家分享了Android无限循环滚动的具体代码，供大家参考，具体内容如下

因项目需要循环展示列表数据，所以就实现了这个无限循环滚动的 LIstView.先说一下原理，原理呢，其实很简单，首先将要展示的数据循环展示三遍

监听ListView的滚动事件，当ListView滚动到第一遍第第二个时，ListView变自动跳到第二遍的第二个，同理，如果ListView滚动到倒数第一个时，ListView自动跳转到第二遍的倒数第一个，然后可以不停的向上或者向下滑动，永远不会到头，废话少说，上

代码：

让ListView循环三遍展示

首先利用取余的方法，将List里面的数据循环展示


public class ListAdapter extends BaseAdapter {
 private List<String> list;
 private LayoutInflater mInflater;
 public ListAdapter(Context context, List<String> list){
 this.list = list;
 this.mInflater = LayoutInflater.from(context);
 }
 /**
 * 将数据循环展示三遍
 */
 @Override
 public int getCount() {
 if(list != null){
  return list.size() * 3;
 }
 return 0;
 }
 @Override
 public Object getItem(int arg0) {
 return list.get(arg0 % list.size());
 }
 @Override
 public long getItemId(int arg0) {
 return arg0 % list.size();
 }
 @Override
 public View getView(int postition, View convertView, ViewGroup arg2) {
 ViewHoler viewHolder = null;
 if(convertView == null){
  viewHolder = new ViewHoler();
  convertView = mInflater.inflate(R.layout.adapter_list_layout, null);
  viewHolder.tvText = (TextView) convertView.findViewById(R.id.adapter_list_layout_tv);
  convertView.setTag(viewHolder);
 }else{
  viewHolder = (ViewHoler) convertView.getTag();
 }
 viewHolder.tvText.setText(list.get(postition % list.size()));//取余展示数据
 return convertView;
 }
 static class ViewHoler{
 TextView tvText;
 }
}

然后实现监听ListView的滚动事件


public class MainActivity extends Activity implements OnScrollListener {
 private ListView listView;
 private List<String> list;
 private ListAdapter adapter;
// private LinearLayout linear;
// 
// private int stopPosition;
// private int firstViewHeight;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    listView = (ListView) findViewById(R.id.listView1);
    list = getList();
    adapter = new ListAdapter(this, list);
    listView.setAdapter(adapter);
    listView.setOnScrollListener(this);
    listView.setSelection(list.size());
  }
  /**
   * 获取数据
   * @return
   */
  public List<String> getList(){
   List<String> list = new ArrayList<String>();
   for (int i = 0; i < 10; i++) {
  list.add(String.valueOf(i));
 }
   return list;
  }
 @Override
 public void onScrollStateChanged(AbsListView view, int scrollState) {
 }
 /**
 * 设置滚动监听，当滚动到第二个时，跳到地list.size()+2个，滚动到倒数第二个时，跳到中间第二个，setSelection时，
 * 由于listView滚动并未停止，所以setSelection后会继续滚动，不会出现突然停止的现象
 */
 @Override
 public void onScroll(AbsListView view, int firstVisibleItem,
  int visibleItemCount, int totalItemCount) {
 /**到顶部添加数据关键代码*/
 if (firstVisibleItem <= 2) {
  listView.setSelection(list.size() + 2);
 } else if (firstVisibleItem + visibleItemCount > adapter.getCount() - 2) {//到底部添加数据
  listView.setSelection(firstVisibleItem - list.size());
 }
 }
}