Step 24: Filtering

介绍

In this step, we add a search field for our product list and define a filter that represents the search term. When searching, the list is automatically updated to show only the items that match the search term.

1.练习效果

Step 24: Filtering - 第1张  | 优通SAP

2.源码

You can view and download all files at Walkthrough – Step 24.

3.webapp/view/InvoiceList.view.xml

The view is extended by a search control that we add to the list of invoices. We also
need to specify an ID invoiceList for the list control to be able
to identify the list from the event handler function
onFilterInvoices that we add to the search field. In addition,
the search field is part of the list header and therefore, each change on the list
binding will trigger a rerendering of the whole list, including the search
field.

The headerToolbar aggregation replaces the simple
title property that we used before for our list header. A
toolbar control is way more flexible and can be adjusted as you like. We are now
displaying the title on the left side with a sap.m.Title control, a
spacer, and the sap.m.SearchField on the right.

4.webapp/controller/InvoiceList.controller.js

We load two new dependencies for the filtering. The filter object will hold our
configuration for the filter action and the FilterOperator is a
helper type that we need in order to specify the filter.

In the onFilterInvoices function we construct a filter object from
the search string that the user has typed in the search field. Event handlers always
receive an event argument that can be used to access the parameters that the event
provides. In our case the search field defines a parameter query
that we access by calling getParameter(“query”) on the
oEvent parameter.

If the query is not empty, we add a new filter object to the still empty array of filters.
However, if the query is empty, we filter the binding with an empty array. This
makes sure that we see all list elements again. We could also add more filters to
the array, if we wanted to search more than one data field. In our example, we just
search in the ProductName path and specify a filter operator that
will search for the given query string.

The list is accessed with the ID that we have specified in the view, because the control is
automatically prefixed by the view ID, we need to ask the view for the control with
the helper function byId. On the list control we access the binding
of the aggregation items to filter it with our newly constructed
filter object. This will automatically filter the list by our search string so that
only the matching items are shown when the search is triggered. The filter operator
FilterOperator.Contains is not
case-sensitive.

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