ToastController not working on load in Ionic 2

I am trying to load the toast as soon as the app loads showing a message such as loading… while the app fetches data from the server then I want to dismiss the toast once the data has arrived or time it out.

I am fetching the data in the ngOnInit() method or angular 2 I have also tried the ionic lifecycle hooks shown here

if I try to show the Toast in ngOnInit() or any ionic nav lifecycle hooks I get the following error

EXCEPTION: Error: Uncaught (in promise): TypeError: activeNav.getActive is not a functionEXCEPTION: Error: Uncaught (in promise): TypeError: activeNav.getActive is not a function
window.console.error(error);app.bundle.js (line 44099)STACKTRACE:
window.console.error(error);app.bundle.js (line 44099)resolvePromise@http://localhost:8100/build/js/zone.js:538:32
scheduleResolveOrReject/<@http://localhost:8100/build/js/zone.js:574:18
Zone</ZoneDelegate</ZoneDelegate.prototype.invokeTask@http://localhost:8100/build/js/zone.js:356:24
NgZoneImpl/this.inner<.onInvokeTask@http://localhost:8100/build/js/app.bundle.js:37230:32
Zone</ZoneDelegate</ZoneDelegate.prototype.invokeTask@http://localhost:8100/build/js/zone.js:355:24
Zone</Zone</Zone.prototype.runTask@http://localhost:8100/build/js/zone.js:256:29
drainMicroTaskQueue@http://localhost:8100/build/js/zone.js:474:26
ZoneTask/this.invoke@http://localhost:8100/build/js/zone.js:426:22

window.console.error(error);app.bundle.js (line 44099)app.bundle.js (line 44108)Unhandled Promise rejection: activeNav.getActive is not a function ; Zone: angular ; Task: Promise.then ; Value: TypeError: activeNav.getActive is not a function
view = activeNav.getActive();zone.js (line 461)Error: Uncaught (in promise): TypeError: activeNav.getActive is not a function
throw new Error("Uncaught (in promise): " + value);

What seems to be the issue here??