Ionic event to identify user came from navCtrl.pop()

Question

I have three pages named as page1,page2 and page3

and their navigation will be page1->page2->page3

How we can identify on page2 that user came on this page via NavController Push or Pop function.

I just want to trigger a function on page2 only if they perform some action on page3 and redirected to page2 via navCtrl.pop() function.

I know i can put condition in ionViewWillEnter for last view name from nav stack, Because it will be fired everytime user be on page2. But If there is any other alternate or good way to do this. Please let me know

Thanks

Answer 1

Identifying if we came to a page using push is easy as it is the standard way of passing a parameter from parent to child in navCtrl.push(PageName, parameters)

I think what you are asking is how to do the opposite: pass a value back from child to parent .

Below is a solution for this (see this link for details):

In parent, instead of the normal push function, create a new promise, and in the then part, you can get a parameter back from the child.

In child, after pop() call its then , and pass a parameter through the resolve of the promise that you initially created to the parent.

Parent

new Promise((resolve, reject) => {
  this.nav.push(ChildPage, {resolve: resolve});
}).then(data => {
  // process data
});

Child

this.nav.pop().then(() => this.params.get('resolve')('some data'))

I have used the above solution many times. There is also this alternative solution, but I haven't tested it myself:

https://forum.ionicframework.com/t/solved-ionic-navcontroller-pop-with-params/58104/3

Answer 2

我正在使用globalThis['datatoinput']来输入我的数据，然后在我的父页面上使用ionViewDidEnter来读取globalThis['datatoinput']