为什么只出来了一行数据？

Question

public class SimpleAdapterActivity extends Activity {

private SimpleAdapter sim_adapter;

private List<Map<String,Object>>datalist;

private ListView lv; 

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_listview);

lv=(ListView) findViewById(R.id.lv1);

//新建一个map键值对数据集合

datalist=new ArrayList<Map<String,Object>>();

//新建一个适配器  适配器加载数据源 

sim_adapter=new SimpleAdapter(this, getData(), R.layout.simple, new String[]{"img1","tv1"} ,new int[]{R.id.img1,R.id.tv1});

//视图加载适配器

lv.setAdapter(sim_adapter);

}

//数据源

private List<Map<String,Object>> getData(){

Map<String,Object> map=new HashMap<String, Object>();//创建一个键值对对象

map.put("img1", R.drawable.img1);//添加键-值对

map.put("tv1", "可爱萝莉");

map.put("img2", R.drawable.img3);

map.put("tv2", "功夫兔");

map.put("img3", R.drawable.img3);

map.put("tv3", "小狐狸");

map.put("img4", R.drawable.img4);

map.put("tv4", "元气少女");

datalist.add(map);

return datalist;

}

}