getBindingContext() is undefined - sapui5

Question

I'm making a little program for a school assignment, but I encounter a problem.
I need to make a program in SAPUI5 that loads JSON data in a table. On each row there is a function (onItemSelected) attached. So when I press on a row, I need to get the ID of the weekday.
This is how the program looks like now:
When I press on a row, it says that my getBindingContext() is undefined.
In my index.html
sap.ui.getCore().attachInit(function(){
var oWeekdagModel = new sap.ui.model.json.JSONModel();
oWeekdagModel.loadData("./model/weekdagen.json");
sap.ui.getCore().setModel(oWeekdagModel, "week");
});
var oResourceModel = new sap.ui.model.resource.ResourceModel({
bundleName : "sap.ui.demo.db.i18n.i18n"
});
sap.ui.getCore().setModel(oResourceModel, "i18n");
new sap.ui.core.mvc.XMLView({
viewName: "sap.ui.demo.db.view.App"
}).placeAt("content");
App.view.xml
<mvc:View
xmlns:l="sap.ui.layout"
xmlns:mvc="sap.ui.core.mvc"
xmlns="sap.m"
controllerName="sap.ui.demo.db.controller.App"
>
<Table id="idWeekdagenTable"
inset="false"
items="{week>/weekdays}"
>
<headerToolbar>
<!-- ... -->
</headerToolbar>
<columns>
<Column width="20%">
<Text text="Id" />
</Column>
<Column width="20%">
<Text text="Weekdag" />
</Column>
<Column width="20%">
<Text text="Aantal gewoon eten" />
</Column>
</columns>
<items>
<ColumnListItem
press=".onItemSelected"
type="Active"
>
<Text id="id" text="{week>id}" />
<Text id="day" text="{week>day}" />
<Text text="{week>no_meals}" />
</ColumnListItem>
</items>
</Table>
<Table id="idMaaltijdenTable"
inset="false"
items="{maaltijd>/meals}"
>
<headerToolbar>
<!-- ... -->
</headerToolbar>
<columns>
<Column width="20%">
<Text text="Maaltijd" />
</Column>
<Column width="20%">
<Text text="Descriptie"/>
</Column>
</columns>
<items>
<ColumnListItem
press=".onItemSelected"
type="Active"
>
<Text text="{maaltijd>MealNo}" />
<Text text="{maaltijd>items}" />
</ColumnListItem>
</items>
</Table>
</mvc:View>
App.controller.js
sap.ui.define([
"sap/ui/core/mvc/Controller"
], function (Controller){
"use strict";
return Controller.extend("sap.ui.demo.db.controller.App", {
onInit: function() {
var oWeekdagModel = new sap.ui.model.json.JSONModel();
oWeekdagModel.loadData("weekdagen.json");
//binding op view
sap.ui.getCore().setModel(oWeekdagModel);
},
onItemSelected: function(oEvent) {
var oItem, oCtx;
oItem = oEvent.getSource();
oCtx = oItem.getBindingContext();
alert(oCtx); // is undefined
}
});
});

Answer 1

You can pull out the day's ID from the model using binding path. Here is a relevant part of your onItemSelected() function:
...
oCtx = oItem.getBindingContext();
var oPressedItem = sap.ui.getCore().getModel().getProperty(oCtx.getPath());
...
and then oPressedItem.id will give you the ID of the day from the top table and oPressedItem.dayId - from the bottom table.
Here is a working example.