Extjs 4 crash on item hide inside FormPanel - exception

Question

I am using extjs 4. When I want to hide an element of a form, It throws the following exception:
ext-all.js:54640 Uncaught TypeError: Cannot read property 'dom' of null
at constructor.isValidParent (ext-all.js:54640)
at constructor.getVisibleItems (ext-all.js:51850)
at constructor.invalidate (ext-all.js:38511)
at constructor.flushInvalidates (ext-all.js:38405)
at constructor.run (ext-all.js:38727)
at Function.flushLayouts (ext-all.js:31218)
at Function.updateLayout (ext-extend.js:2973)
at constructor.updateLayout (ext-all.js:32266)
at constructor.onContentChange (ext-all.js:29697)
at constructor.updateLayout (ext-all.js:32263)
The form is like this:
this.ReqDetails = new Ext.FormPanel({
width: 510,
height: 600,
style: ' padding:5px 5px 5px 5px',
autoScroll: true,
align: 'right',
defaults: {
labelWidth: 200,
style: 'display:block; padding:1px 5px 1px 5px;font-weight: bold',
layout: 'fit'
},
layout: {
type: "table",
columns: 2
},
// listeners:{'afterlayout':function(){RequestDetailsObject.ShowItem()}},
items: [
...
]
,
renderTo: this.get("RwqDetdiv"),
});
and the logic is like this:
var itemsToEnable = null;
if (enableItem != '') {
itemsToEnable = Ext.decode(enableItem);
console.log("enable items: ", itemsToEnable);
}
var win = RequestDetailsObject.ReqDetails;
var record = Ext.decode(response.responseText).DetList[0];
...
win.down("[itemId=analyzer]").setValue("test");
...
win.show();
if ((record.analyzer == null || record.analyzer == "") && (itemsToEnable == null || itemsToEnable.indexOf("analyzer") < 0)) {
win.getComponent("analyzerTit").hide();
win.getComponent("analyzer").hide();
}
the error occurs at this line:
win.getComponent("analyzerTit").hide();
It is worth noting that win.down("[itemId=analyzerTit]").hide(); also has same behavior, And win.down("[itemId=analyzer]").setValue("test"); works in the above code.

Answer 1

You are getting this issue because of your DOM is not created. For more details you can refer this links SENCHA forum and FIDDLE to understand Uncaught TypeError: Cannot read property 'dom' of null this error.
You can handle this error at your end using following code
var analyzerTit = win.getComponent("analyzerTit");
if (analyzerTit && analyzerTit.getEl()) {
analyzerTit.hide();
}