问题
This question and its answers (copied below) provide a solution for handling the back button in Ionic, but that solution only works when other pages are pushed directly from app.component, in which case calling canGoBack and getActive() on this.nav works correctly because other pages have been pushed using this.nav.push in app.component.
However if a page is pushed from one of the pages in the tabs (lets call it page1), i.e. by calling this.navCtrl.push() in page1, then this.nav.canGoBack() in app.components still resolves to false because the push happened using the page1's this.navCtrl.push() not app.component's this.nav.push().
How can I detect inside app.components if a page was pushed from any of pages in the tabs?
platform.registerBackButtonAction(() => {
if(this.nav.canGoBack()){
this.nav.pop();
}else{
if(this.alert){
this.alert.dismiss();
this.alert =null;
}else{
this.showAlert();
}
}
});
});
}
来源：https://stackoverflow.com/questions/46757910/handling-back-button-in-ionic-3-with-tabs