run the activity while it's not visible

Question

I'm working now in a project to download images from the web and then show it after completing its download.

i made an activity class that has a button and text field and when the user press on the button, i started a service which will show a notification in status bar and after download i will show a message .

my main problem now is i want to go to other application or home page while the download is working.

i tried it but i after the download i got the message ,,, " Force quit"

should i use broadcast receiver or remote server to handle what i want.

Thanks,

Answer 1

Activities are just that, activities, they only work when visible and are built strictly for user interaction or a user activity, so this is impossible. Use a service instead. Here is a diagram showing lifespan of an activity:

Link to App activity explanation on Android developer site

Answer 2

You may need to call Looper.Loop() in your service to keep it running if you have any listeners in your service.

Answer 3

The service should be the one downloading the content. If you go to the home activity our activity calls onPause, stoping all the work in progress.