Popover position and transition

Hello, EveryOne,
I’m trying to use ionic2 to create my new app, I use Popover components, but I have a problem with setting the position of popover, I wanna to set popover at the bottom and slide up to present. Now I use the below code to set the position.

export class MyPopover {
    private selectContent;
    ngOnInit() {
        this.popoverContent = document.querySelector('.popover-content')
    onPageDidEnter() {
        this.selectContent.style.bottom = 0
        this.selectContent.style.left = 0
        this.selectContent.style.top = 'auto'

The problem is the popover will jump to bottom, I try to figure out a better to way to show popover with transition, anyone have idea? tks

em… After some search, I think I find out a way to resolve this problem, but I don’t think it’s a smart way.
I read code of Popover component find there is no API to change the position of Popover before rendering, the only way is to rewrite the Popover render class. So… more complex but worked