xlistView下拉刷新，上拉加载更多

<1>、MainActivity代码
public class MainActivity extends AppCompatActivity implements XListView.IXListViewListener {

private List list;
Handler handler=new Handler(){

    @Override
    public void handleMessage(Message msg) {
        super.handleMessage(msg);

        adapter.notifyDataSetChanged();

        close();

    }
};
private MyAdapter adapter;
private XListView lv;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    lv = (XListView) findViewById(R.id.lv);

    initDate();

    lv.setPullLoadEnable(true);
    lv.setPullRefreshEnable(true);
    lv.setXListViewListener(this);

    adapter = new MyAdapter();
    lv.setAdapter(adapter);
}


public void close(){

    lv.stopRefresh();
    lv.stopLoadMore();

    SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy 年 MM 月 dd 日   HH:mm:ss");
    String format = simpleDateFormat.format(new Date());
    lv.setRefreshTime(format);

}

private void initDate() {
    list=new ArrayList<>();
    for(int i=0;i<10;i++){

        list.add("想要宝马*"+i);
    }
}

/**
 * 下拉刷新
 */
@Override
public void onRefresh() {

    handler.postDelayed(new Runnable() {
        @Override
        public void run() {

            list.add(0,"送你一辆宝马X6");
            handler.sendEmptyMessage(0);
        }
    },2000);

}

/**
 * 上拉加载更多
 */
@Override
public void onLoadMore() {

    handler.postDelayed(new Runnable() {
        @Override
        public void run() {
            list.add("送您多个豪车");
            handler.sendEmptyMessage(0);
        }
    },2000);

}