Develop Reference

Can I make an iOS/Android app "ring", to force the user to respond to a push notification?

I have a food ordering app and I need to inform the restaurants of a new order. I have a Capacitor app which often runs in the background of tablets/phones of the restaurant. As a result, they sometimes miss an order.
In order to solve this, it would be great if I could ring the device as if an alarm goes off or if the device gets a call. Then they can swipe away the notification to stop it or something like that, to make sure they saw it. I would choose the sound myself so that it isn't obnoxious.
Is anything like that possible?

yes it's possible but,
you should know the following:
for Android:
1-create a foreground service to keep notification appears to the
restaurants, in this case the restaurant can not hide the
notification.
once the restaurant receive the notification just
sent an event to the foreground service to handle the action and the
data.
start the order activity from foreground service, once the
activity is created just play a sound.
for IOS,
it should be the same but i don't know how to create a foreground service in IOS.

Cancel notification without using Notification Manager

I have an application in which it receives the notification when fired from Backend. Now what I want to achieve is that the notification should disappear after 2 minutes if user has not clicked on it (even if my app is killed or background). I know that this can be achieved by using the Notification manager's setTimeoutAfter() but that will work only if am making my custom notification using Notifcation Manger.But i want to dismiss the Notification generated by System after 2 minutes.
Any kind of suggestion or help will be welcomed.

It is not possible to do that. The default system notification builder is pretty bare bones and will not handle it. The best you can do is set a delivery timeout so if the device was off it won't get the notification once it expires.
See https://firebase.google.com/docs/cloud-messaging/concept-options#when_to_use_platform_specific_keys (only works on Android and Web)

In android, is it possible to create a notification when another app is opened?

I'd like to know if it is possible to create a notification or toast/alert from my app when another app is opened. For example, my app Foo will create a notification if Facebook is opened.
Edit: What I actually want is to inform the user that my app is running in the background when the default camera app opens/running. My app will modify photos taken with the default camera app when it is running in the background and I want to inform the user that it will do so. Is this possible?

Basically what you want is a push notification. Please go through following tuts to help yourself:
https://neurobin.org/docs/android/push-notification-gcm-client-server/
https://developers.google.com/cloud-messaging/android/start

Yeah, you can take a look at this and then schedule an alarm using some background running process that looks for Facebook being running.
One way is to use AlarmManager to check running apps every 5-10 mins and you can generate a notification if your condition is met.

How to display dialog box from from c2dmreceiver in android

At present i am working on c2dm in android.i am sending messages from server but messages are displaying on Log cat.But i want to display dialog when message occur how can i do this.
Please help me.

Maybe you should use the notifications framework to notify the user by dropping an icon in the notification bar. This is less obtrusive, but gives the user some visual cue that something has happened.

First, you cannot display dialog boxes from broadcast receivers. At most, you can start up an activity, perhaps one themed to look like a dialog.
Second, popping up an activity like this is generally frowned upon. You have no idea what the user is doing at the time, and they may not appreciate your activity taking over the foreground. Only a select handful of applications (VOIP clients, alarm clocks, etc.) should do this sort of thing.

Android: Display Notification as an activity instead of adding it to status bar

I m a newbie to android development and i wanna know a right way to get notification as an activity instead of statusbar notification.
To be clear, i wanna display an notification on screen instead of adding it to status bar.

In that case you shouldn't call it notification. In Android, a notification is something that ends up in the status bar and that the user can deal with at her own leisure.
An activity will take over the complete screen and force the user to deal with it immediately. That is very intrusive and users will likely get annoyed, unless the information you show is really crucial.
The correct behaviour is to post a notification and bring up your activity when the user clicks on the notification, very much like your messaging client or email client.
Other options are bringing up a dialogue or a toaster message. A dialogue is a message the user will have to interact with to go away, whereas a toaster message will be visible for a short time and then automatically disappear.
Maybe you could be a bit more specific about what sort of information you want to provide to the user?

Surely you can be helped out.
I feel that you are getting notifications from a web service as a response to some request, right?
If yes, then you can display them in a custom made dialog box, or inside an activity whose theme has been set as DIALOG.
maybe I got your question wrong, maybe your talking about the notifications about networks, calls and things.
If its so, correct me.
Thanks!

Android 2.3 introduced a new field on Notification, fullScreenIntent, for exactly this purpose. Place a PendingIntent here that will trigger whatever activity you'd like to display, and the user will be sent to that activity (whether full-screen or dialog-themed) in addition to receiving the usual notification icon in the status bar. As of Gingerbread, this is how the Phone app implements the incoming call screen.