Android Question Switch from background to foreground

[Sganga61]

HI
my question is: simple: when I close my application, it remains active in background so I can receive and view notifications while I use other applications.
What can I do to wake my app from background to foreground state without restarting or reinitializing it?

 

[Erel]

There are two different questions here:
1. How can you "wake" your app?
The answer is that it is usually the user that brings the app to the foreground. You can do it programmatically from a service or receiver but it requires special permission.

2. About restarting the app. The app will not be restarted if it wasn't killed by the OS.
Switch to B4XPages. It simplifies many things.
If you want to continue the app state even after the OS killed the process then you need to save the state with KeyValueStore or any other persistent method.

 

[Sganga61]

Hi Erel
1) about to wake the app there is an example to study?
2) about this second point it is clear

Thank you

 

[DonManfred]

1) about to wake the app there is an example to study?

See this in general.

android.jar / targetSdkVersion / minSdkVersion

There are several versioned components that affect the compilation process and the runtime behavior of our apps. The purpose of this tutorial is to explain the differences between them and help you choose which version to use. Each Android version is mapped to an api level. You can see this...

www.b4x.com

and especially:
Additional changes in Android 10 that are not related to the targetSdkVersion value:

• StartActivity from a service will not work if there is no visible activity. As a workaround you can request the special "draw over apps" permission: https://www.b4x.com/android/forum/threads/draw-on-top-of-other-apps-permission.90513/
  It will allow StartActivity to work.

 

[Sganga61]

See this in general.

android.jar / targetSdkVersion / minSdkVersion

There are several versioned components that affect the compilation process and the runtime behavior of our apps. The purpose of this tutorial is to explain the differences between them and help you choose which version to use. Each Android version is mapped to an api level. You can see this...

www.b4x.com

and especially:
Additional changes in Android 10 that are not related to the targetSdkVersion value:

• StartActivity from a service will not work if there is no visible activity. As a workaround you can request the special "draw over apps" permission: https://www.b4x.com/android/forum/threads/draw-on-top-of-other-apps-permission.90513/
  It will allow StartActivity to work.

Hi DonManfred
thanks for replay.
I just need a NOTIFICATION when the app is in background
In the first time I follow the example of Erel using NB6 library. In that example there is no auth required.
Mu app works fine on local device (debug or Release) but When I put the file on the Play Store (as not visible test app) they crash anytime on device with Android 14.
You think I can solve with this workaround?

 

[Sagenut]

Hi DonManfred
thanks for replay.
I just need a NOTIFICATION when the app is in background
In the first time I follow the example of Erel using NB6 library. In that example there is no auth required.
Mu app works fine on local device (debug or Release) but When I put the file on the Play Store (as not visible test app) they crash anytime on device with Android 14.
You think I can solve with this workaround?

Did you check this?
https://www.b4x.com/android/forum/threads/notifications-permission-with-targetsdkversion-33.148233/

 

[Erel]

As answered above, you don't need to move the app to the foreground in order to show notifications.