加载json数据后extjs4表单仍然为空

Question

I'm beginning going crazy with extjs4 and form loading. In my struts application, I have a simple form and i want to load JSON data.

The problem is that the data are correctly loaded from the server but never displayed.

Here is the code :

Ext.onReady(function(){

var formPanel = Ext.create('Ext.form.Panel', {
    renderTo: Ext.get('categoryForm'),
    width: 340,
    bodyPadding: 5,
    waitMsgTarget: true,
    url: '<s:url value="json/save" />',
    method: 'POST',

    loader: {
        type: 'json',
        root: 'category',
        successProperty: 'success'
    },

    fieldDefaults: {
        labelAlign: 'right',
        labelWidth: 85,
        msgTarget: 'side'
    },
    defaultType: 'textfield',

    items: [{
        name: 'category.id',
        hidden: true
    }, {
        fieldLabel: "<s:text name="category.label"/>",
        name: 'label',
        allowBlank: false,
        maxLength: 35
    }, {
        fieldLabel: "<s:text name="category.description"/>",
        name: 'description',
        xtype: 'textarea',
        maxLength: 250
    }, {
        fieldLabel: '<s:text name="category.creationDate"/>',
        name: 'creationDate',
        xtype: 'datefield',
        readOnly: true
    }],

    buttons: [{
        text: "<s:text name="action.modify"/>",
        handler: function() {
            formPanel.getForm().submit();
        }
    }, {
        text: "<s:text name="action.cancel"/>",
        handler: function() {
            formPanel.getForm().reset();
        }
    }]
});
formPanel.show();

formPanel.load({
    url: '<s:url action="json/load"/>',
    params: {
        categoryId: <s:property value="categoryId"/>
    }
});
});

The JSON data (intented) response :

{
    "category":
    {
        "creationDate": "2012-04-14T22:29:52",
        "description":"description",
        "id":1,
        "label":"Toto"
    },
    "errorMessage":null,
    "success":true
}

Answer 1

Finally I found where was the problem.

The JSON response must contains the 'data' property instead of 'category'.

Replacing the property fill the form.