I have several pages in test app.
If each pages name is as page1, page2, page3 …
If I leave from page1 to page2, then how to disable all methods from previous page?
Problem is using on NFC API on each pages, but always working previous methods even if I leave there.
How to disable or initialize it? 
Page1
…
ionViewDidEnter() {
this.nfc.enabled().then(() => {
this.addListenNFC();
}).catch(() => {
alert("NFC not support.");
});
}
ionViewWillLeave(){
this.nfc.unshare(); //even if I wrote this, it working when I leave this page…
//How to implement code to disable below methods?
}
// NFC event register
addListenNFC() {
this.myListener = this.nfc.addTagDiscoveredListener((data) => {
return data;
}, (err) => {
this.popupService.showCommonPopup(err);
alert('NFC not detected!');
}).subscribe((event) => {
this.myListener.unsubscribe(); //remove NFC Event
return this.onNfcLogin(event);
});
}
onNfcLogin(data) {
if (data && data.tag && data.tag.id) {
this.scanned = true;
this.tagId = this.nfc.bytesToHexString(data.tag.id);
this.userService.nfclogin(this.tagId).subscribe(data => {
this.granted = true;
this.popupService.showCommonPopup(data);
this.resetScanData();
this.loading.dismiss();
this.events.publish('user:login');
this.navCtrl.pop();
},
error => {
this.denied = true;
alert('This card is not registered');
this.resetScanData();
this.loading.dismiss();
this.events.publish('user:login');
this.navCtrl.pop();
});
}
}