import {LoadingController} from ‘ionic-angular’
let loading = this.loadingCtrl.create({
content: ‘Please Wait’,
});
loading.present();
Package.json
"ionic-angular": “3.4.2”
When presented, it only shows ‘Please Wait’ with no spinner. According to the doc, it should show a spinner based on the mode.
It’s probably because you have a comma after the content property, so it’s sending null options to the loading controller.
Unfortunately removing the comma did not change anything, the spinner is still not showing 
Also my constructor has public loadingCtrl: LoadingController
Try to recreate the problem in a blank project (ionic start blank blank
) please. If you can, post it to Github and show us. If you can’t you just found how to solve your problem by comparing the two projects. 
Hello @Li_eric,
I have the same issue, did you found any solution for that ?
Thanks.