Event for view leave - sapui5

Question

I declared a controller for a view in my SAPUI5 application. Now I want to perform tasks when the view is left by the user.
There is already a possibility to add a callback function to attachRoutePatternMatched to perform tasks when the view is navigated by the user now I need a equivalent function to handle a leave of the view. I use a SplitContainer as parent container
onInit: function() {
this._oRouter = this.getOwnerComponent().getRouter();
this._oRouter.attachRoutePatternMatched(this._routePatternMatched, this);
},
_routePatternMatched: function(oEvent) {
var that = this;
var sRouteTargetName = oEvent.getParameter("name");
if (sRouteTargetName === "myView") {
// perform tasks if the view is opened by the user
}
},

Answer 1

You can try if this works:
navAway: function(viewName, callback) {
this._oRouter.navTo(viewName);
if(callback && typeof(callback) === "function") {
callback();
}
}
e.g. this.navAway("myView", function() { //doStuff });

Answer 2

Presume you mean navigating backwards? If you have a back button, which presumably you must, put your actions in that function. E.g your detail/master has a navBack button in the toolbar, so put your logic in the button's event handler...

Answer 3

You can achieve this with BeforeHide delegate on the NavContainer child which is often the view:
onInit: function() {
this._navDelegate = { onBeforeHide: this.onBeforeLeave };
this.getView()/*<-- navContainerChild*/.addEventDelegate(this._navDelegate, this);
},
onBeforeLeaving: function(event) {
// ... do something
},
onExit: function() {
// detach events, delegates, and references to avoid memory leak
this.getView().removeEventDelegate(this._navDelegate);
this._navDelegate = null;
},
Example: https://embed.plnkr.co/wp6yes?show=controller%2FNext.controller.js,preview%23next
API reference: NavContainerChild
API reference: sap.ui.core.Element#addEventDelegate
For other navigation related events, see documentation topics mentioned in https://stackoverflow.com/a/55649563