Receive and handle topic messages - shaikhalvee/FCM GitHub Wiki

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App state	Notification	              Data	                Both
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Foreground	onMessageReceived	onMessageReceived	onMessageReceived
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Background	System tray	        onMessageReceived	Notification: system tray
                                                           Data: in extras of the intent.
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So, if you have data payload, onMessageReceived will be always called.