使用Appcelerator Alloy动态定位UI元素?

有没有一种方法可以针对特定的合金UI元素 ? 我想这样传递一个变量:

控制器。js公司

var flag = "se";
changeBackground(flag); //should change the background color of ImagView of the se flag


function changeBackground(elementToChange){
    elementToChange.backgroundColor = "red"; //does not work
   $. + elementToChange +  backgroundColor = "red"; //does not work
}

看法xml

<View id="flagRow" layout="horizontal" backgroundColor="blue" height="Ti.UI.SIZE">
    <ImageView id="se" height="20dp" left="5dp" image="/images/flags/se.png" onClick="downloadPastLanguageLevels"/>
    <ImageView id="de" height="20dp" left="10dp" image="/images/flags/de.png" onClick="downloadPastLanguageLevels"/>
    <ImageView id="en" height="20dp" left="10dp" image="/images/flags/en.png" onClick="downloadPastLanguageLevels"/>
            </View>

var i, view;
    for (i in $.flagRow.children) {
            view = $.flagRow.children[i];
            if (view.id.indexOf(flag) > -1) { 
                view.backgroundColor = "red";
            } else {
                view.backgroundColor = "transparent";
            }
        }