android程序运行后长按不弹出菜单，找不到原因。

Question

public class Chan_List extends ListActivity {

private ScanActivity sActivity = null;
private static final String TAG = "RCU";
private SimpleAdapter listAdapter = null;
private MobileControl mControl=null;
private ListView show;
private List<Map<String, Object>>chanlist=new ArrayList<Map<String, Object>>();
Map<String, Object> map;
public Chan_List() {
    // TODO Auto-generated constructor stub
}
@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    mControl = (MobileControl) getApplicationContext();
    setContentView(R.layout.chan_list);
    map=new HashMap<String, Object>();
    map.put("chan_index", "1.");
    map.put("chan_name", "CCTV10");
    chanlist.add(map);
    listAdapter = new SimpleAdapter(Chan_List.this, chanlist,
            R.layout.chanlist, new String[] { "chan_index",
                    "chan_name"  }, new int[] {
                    R.id.chan_index, R.id.chan_name });

    setListAdapter(listAdapter);

show= new ListView(this);
registerForContextMenu(show);

}

@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo) {
// TODO Auto-generated method stub
super.onCreateContextMenu(menu, v, menuInfo);
menu.add(0,0,0,"sort");
menu.add(0,1,0,"delate");
menu.add(0,2,0,"move");

}
@Override
public boolean onContextItemSelected(MenuItem item){
AdapterView.AdapterContextMenuInfo info =(AdapterView.AdapterContextMenuInfo)item.getMenuInfo();
switch (item.getItemId()) {
case 0:
Toast.makeText(Chan_List.this, "he", Toast.LENGTH_SHORT).show();
break;

default:
    break;
}
return super.onContextItemSelected(item);       

}
}

Answer 1

长按的响应函数有错。