Call function from controller from within event function of a responsivepopup - sapui5

Question

I have a responsivepopup containing a list in mode 'Delete'.
When I click to delete an item a function is called on press.
Withing this function 'this' is the oList and oEvent.oSource is also the oList.
From within the event function I need to call a function in my controller.
I can't find a way to reference my controller, not even using sap..core..byId("Detail") or even the full namespace.
I tried walking up the elemnt tree from oEvent.oSource.getParent().getParent() to then call .getController() but it's a dead end.
handlePressViewSelection: function(oEvent) {
var oResourceBundle = this.getResourceBundle();
//create the list
var oList = new sap.m.List({
mode: "Delete",
delete: this.handleDeleteSelectionItem
});
oList.setModel(this._oSelectedTrainingsModel);
var oItemTemplate = new sap.m.StandardListItem({
title : "{Title}",
description : "{=${Begda} ? ${Type} - { path: 'Begda', type: 'sap.ui.model.type.Date', formatOptions: { style: 'medium' }} : ${Type}}",
icon : "{icon}",
iconInset : false
});
oList.bindAggregation("items", {
path: "/",
template: oItemTemplate,
type: "Active"
});
var oBeginButton = new sap.m.Button({
text: "Action1",
type: sap.m.ButtonType.Reject,
press: function(){
oResponsivePopover.setShowCloseButton(false);
}
});
var oEndButton = new sap.m.Button({
text: "Action2",
type: sap.m.ButtonType.Accept,
press: function(){
oResponsivePopover.setShowCloseButton(true);
}
});
var oResponsivePopover = new sap.m.ResponsivePopover({
placement: sap.m.PlacementType.Bottom,
title: "",
showHeader: false,
beginButton: oBeginButton,
endButton: oEndButton,
horizontalScrolling: false,
content: [
oList
]
});
oResponsivePopover.openBy(oEvent.oSource);
},
handleDeleteSelectionItem: function(oEvent) {
var oListItem = oEvent.getParameter('listItem');
var oList = oListItem.getParent();
var path = oListItem.getBindingContext().sPath;
oList.getModel().getData().splice(parseInt(path.substring(1)), 1);
oList.removeItem(oEvent.getParameter('listItem'));
oList.getParent().getParent().getController()._updateViewSelectionButtonText(); //--> BROKEN
},

Answer 1

When you instantiate your popup from a fragment, you can specify "a Controller to be used for event handlers in the Fragment" (see https://sapui5.hana.ondemand.com/#docs/api/symbols/sap.ui.html#.xmlfragment)
For example:
onOpenResponsivePopover : function(oEvent) {
if (!this._oResponsivePopover) {
// adding 'this' makes sure you specify the current controller to be used for event handlers
this._oResponsivePopover = sap.ui.xmlfragment("namespace.to.your.popoverfragment", this);
this.getView().addDependent(this._oResponsivePopover);
}
this._oResponsivePopover.openBy(oEvent.getSource());
},