extjs4 tree 节点选中问题

//右侧菜单树
var centerPanel = Ext.create('Ext.tree.Panel', {
……
listeners:{
checkchange:function (node,checked,eOpts){
//选中事件
setChildChecked(node,checked);
setParentChecked(node,checked);
}
}
});

function setChildChecked(node,checked){
node.expand();
node.set({checked:checked});
if(node.hasChildNodes()){
node.eachChild(function(child) {
setChildChecked(child,checked);
});
}
}
function setParentChecked(node,checked){
node.set({checked:checked});
var parentNode = node.parentNode;
if(parentNode !=null){
var flag = false;
parentNode.eachChild(function(child) {
if(child.data.checked == true){
flag = true;
}
});
if(checked == false){
if(!flag){
setParentChecked(parentNode,checked);
}
}else{
if(flag){
setParentChecked(parentNode,checked);
}
}
}
}