在SAP WebClient UI裡使用AJAX進行非同步資料讀取

What is smart field

According to  SAP help, “Smart controls are a specific category of SAPUI5 controls that have some special features in addition to the standard SAPUI5 features and thus make it easier to use the control in certain scenarios. One important building block of smart controls is the SmartField control that, depending on the OData metadata defined, allows you to renders other controls and, for example, define fields with certain attributes based on the metadata.”

In xml view definition, only one SmartLabel and one SmartField are declared.

However, in rendered UI, there is additional currency field displayed as well. This is the meaning of “Smart”.

How SmartField works

(1) SmartField which is bound to Price field is rendered as usual:

(2) The mock data, Products.json, will be loaded by Mock server and once it is available, success callback is triggered.

(3) In callback, setElementBindingContext will trigger initialization logic of SmartField:

(4) Here ODataControlFactory will try to get all sap defined annotation from OData Metadata,

The picture above highlights some of sap annotations. For a complete list of them, please refer to this  link.

Parse logic of all annotations could be find from AnnotationHelper.get. The example below introduces how sap:unit annotation is parsed.

The string “CurrencyCode” is returned:

At this time, metadata for currency UI element is available and it is ready for creation:

(5) UI element for currency code display is created here:

And CSS class sapUiCompSmartFieldUnit is added:

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