NativeScript / NativeScript/android

App killed when starting a foreground activity on some devices

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Dominant language
C++
Stars
563
Forks
144
Avg merge
10h 46m
Merged PRs (30d)
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Description

Environment
Provide version numbers for the following components (information can be retrieved by running tns info in your project folder or by inspecting the package.json of the project):

  • CLI: 6.5.0
  • Cross-platform modules: 6.5.1
  • Android Runtime: 6.4.1
  • Plugin(s):
    @nstudio/nativescript-checkbox
    nativescript-bitmap-factory": "^1.8.1",
    nativescript-bluetooth
    nativescript-camera
    nativescript-drawingpad
    nativescript-feedback
    nativescript-fonticon
    nativescript-geolocation
    nativescript-iqkeyboardmanager
    nativescript-localize
    nativescript-modal-datetimepicker
    nativescript-print-zebra
    nativescript-printer
    nativescript-sqlite
    nativescript-sqlite-commercial
    nativescript-sqlite-encrypted
    nativescript-toasty
    nativescript-zip

Describe the bug
On some devices, at least on Huawei Mediapad T5, when I start a new activity that goes on the foreground, the NativeScript activity gets killed. When I go back, the NS activity restarts.
After some investigation, I concluded that it's a battery management issue. Android always kills app activities put in the background to minimize battery usage, but on some devices (mainly Huawei from what I've found) this mechanism is very aggressive and kills the activity immediately after it goes in the background. The Android activityDestroyed event and NS exit event are not called.

I have two scenarios:

  • Opening the camera with nativescript-camera plugin. The NS activity is killed but the camera still works, allowing me to retrieve the photo uri on restart.
  • Printing with the system service PrintManager. In this case, when the NS activity is killed the print tool closes too. To the user, it looks like a crash.

My goal is to prevent the perceived crash at least on the second scenario. Is there a way to release enough resources when the activity is paused?

Allowing the app to ignore battery optimization and managing manually launch/app launch doesn't solve the issue.

To Reproduce
Launch the nativescript-camera demo on an affected device.

Expected behavior
The NS activity is not killed after it starts a new activity.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the NativeScript camera demo and reproduce the lifecycle on an affected Huawei Mediapad T5. Trace the activityDestroyed and NativeScript exit events while launching the camera or Android PrintManager, then compare the result with the expected behavior that the NativeScript activity remains usable after starting a foreground activity.

Written by the indexing model from the issue text.

Assessment

Tech stack
android
Domain
mobile
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
30/100

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