I am working on a chat app in Android using c2dm (gcm). Every received message raises a notification if my app is not able to show it directly. The problem is when the user is off the grid, in which case c2dm messages stack up and get delivered all at once when he is back online. A cacaphony of notification sounds is the result from adding all the notifications in a 1 second period. How to prevent this? Desired behaviour is a that the notification sound is played once, while the tickertext and notification content are up to date with the last received message
I ended up using an alarm wich was set 1 second into the future. I set multiple alarms with the same intent, the earlier ones are automatically deleted. So when a second one comes in in the 1 second interval it deletes the first.
Utilize the collapse_key to only process the last "notification" of the stack
For more info, see https://developers.google.com/cloud-messaging/concept-options#collapsible_and_non-collapsible_messages
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I am developing an android app which is about meal subsciption.
I update the entire menu(breakfast, lunch , dinner) for each day in the morning( I am using firebase).
Now i want to send scheduled notification to users that is, i want to notify a user at 1pm that this is the coming menu for the lunch similarly i want to notify the user at around 8pm that this is the coming menu of dinner.
What should i use to get this scheduled notification?
I had an idea in mind that when i update the database in the morning. I will send a data payload with the required scheduling time using cloud messanging and schedule the notification on the device itself.
Will this work?
Yes, it will work, I recommend using Worker to schedule notification and take into account receiving notifications while the app is in the background, because your app should have that feature I guess.
When using FCM Notification Channels - it is no longer possible to change the Notification Sound when a notification arrives (using SetSound()). This is causing me a problem when my app receives a notification while the audio of a previous notification is playing. Our notification sound bites are 2-3 seconds long each, and when the second notification arrives, it cuts the first notification's audio off.
Instead of delaying the second notification from displaying, I would like for the second notification to display, but not play any audio. Is this possible?
I don't think you have that level of control over how Android displays/plays incoming notification messages.
The only approach I can think of is taking full control of the display of the messages in your own application code, by using data messages instead of notification messages.
Reminder: Firebase Cloud Messaging has two message types: notification messages, and data messages. Notifications messages are automatically handled/displayed by the OS when your app is not active, while data messages are always delivered to your application code.
From within your application code, you can then use the Android notification API to build the exact display of the message that you want, and display it exactly when you want it (within the notification settings of the user of course).
I want my app to notify users of specific events that can occur at a certain time.
I know how to send a notification knowing the exact time of it, but things get a little complicated for me when I want to trigger notifications at times that are unknown at app install (notifications whose time can change or which depend on a specific event).
Here are two cases in which I don't know how to trigger a notification :
Send a notification every day at a time that can change from day to day. Say I want to notify users that it's sunrise time, do I need a Service to run permanetly an calculate for each day the time of sunset and trigger a notification when the time comes ?
Send a notification everytime something new in the community occurs. I don't want to notify users of an update, but just of a particular event at a certain time. How do I send notifications to them?
How can I achieve this ?
Thanks !
For your first option i would use a AlarmManager. It will execute a function on a specific time, that can be set on app startup. Everytime the AlarmManager executes and sends a notification to the user, it should re-calculate the next message time and reset the AlarmManager. ( see how to reset here )
For your second scenario you could use a library like OneSignal. It's a verry usefull library for registering users for pushnotifications and sending messages from a website to your users. You can choose groups of users or specific users for sending messages and you can customize the look of your pushmessages ( add buttons, images, .. etc).
I'm creating a very simple application for myself. Basically, it gives me a certain notification exactly every 2 hours.
The problem is when I don't "check" the notification for 2 hours and the next notification is supposed to come around. It sends a notification even though another notification already exists.
I'm simply sending notifications with NotificationManager.
Is there a way to check if previous notification already exists and only send another one if it doesn't?
Assuming you are using the same notification id (so that only one notification appears in the notification tray), you can use setOnlyAlertOnce(true) to ensure that sound/vibrate only plays the very first time a notification is posted and not when an existing notification is updated.
My app pops up a message count notification and sets it as "ongoing". There is a timer that re-sends the notification every 5 minutes, and the notification has the flag Notification.FLAG_ONGOING_EVENT , so that it can only get cleared by my app. And my app is set up to only use sound and vibrate if the count changes.
So, the idea is that if my app changes the count, it sends out an updated notification, which replaces the old one, and plays a sound and vibrates. But if the 5 minute timer tries to update the notification, but the count didn't change, the notification is still sent. but without sound or vibrate. This is done in case the notification somehow got cleared, I want it to pop back up, but if it's still there, I don't want the user to be re-notified.
I also save the message count so that it's remembered if the app is closed and then re-opened. The problem is that when that happens (if it's force-closed, for example), the old notification stays in the bar, but the newly opened app has no idea that's the case. So I'd like to be able to somehow poll the notification service to see if that original notification is still showing, but I can't find any API to do this. Is it possible?
Thanks.
So I'd like to be able to somehow poll the notification service to see if that original notification is still showing, but I can't find any API to do this. Is it possible?
No.
However, you can use deleteIntent to find out if the user cleared the Notification. Either that, or track down the cause of your "somehow got cleared" issue.