PopPicker 需要按两次以上才出来

自定义的数据，从sqlite中获取数据，很不灵敏，需要按多次才弹出选择界面，选择界面出现过一次以后，就灵敏了，每次按都出来
function getcheckoutday(){

            var sql = 'select RecoId as value,Cname as text From basecheckoutday Where RecoType = "1" Order By BillNo; '  

            db.doQuery(sql, function(result) {  

                var userPicker = new mui.PopPicker();  
                userPicker.setData(result);  
                var showUserPickerButton = document.getElementById('checkoutday');  

                showUserPickerButton.addEventListener('tap', function(event) {  
                    userPicker.show(function(items) {  
                        showUserPickerButton.setAttribute("data-col", items[0].value);  
                        showUserPickerButton.value = items[0].text;  
                        userPicker.CLOSED;  

                        //返回 false 可以阻止选择框的关闭  
                        //return false;  
                    });  
                }, false);                    

            });                   

    }