this.fcm.onNotification().subscribe() not called on Android device - push-notification

Question

I have an Ionic 4 app which I have integrated with Firebase for authentication etc. I want to implement Firebase's cloud messaging so I can push messages to my app on both Android and iOS. I have done this pretty easily on iOS and I have sent a message via Postman which shows on my iPhone and I see the JSON of the message I have sent. When I try it on Android it doesn't work. Both devices receive the message but handle it very diferently.
I have read in a lot of places that you need to set the click_action to FCM_PLUGIN_ACTIVITY but when I do that the app doesn't even open on Android. When I take it out the app loads when you click the message but it doesn't show the body of the message like on iOS in my alert.
import { FCM } from '#ionic-native/fcm/ngx';
...
constructor(public platform: Platform, public fcm: FCM)
...
this.platform.ready().then(() => {
this.fcm.onNotification().subscribe(data => {
alert(JSON.stringify(data));
});
this.fcm.onTokenRefresh().subscribe(token => {
// Register your new token in your back-end if you want
// backend.registerToken(token);
});
}).catch((error) => {
this.showFailureMessage(error.message);
});
This is what I am posting off to... https://fcm.googleapis.com/fcm/send
{
"notification":{
"title":"My Title",
"body":"My Body",
"sound":"default",
"click_action":"FCM_PLUGIN_ACTIVITY"
"icon":"fcm_push_icon",
},
"data":{
"type":"Something",
},
"to":"/topics/all",
"priority":"high",
"restricted_package_name":""
}
Any help would be very much appreciated.

Answer 1

You seem to be missing the data.wasTapped part in your subscribe. Here, try this:
this.fcm.onNotification().subscribe(data => {
if (data.wasTapped) {
alert('Received in background');
alert(JSON.stringify(data));
} else {
alert('Received in foreground');
alert(JSON.stringify(data));
}
});