Hello!
This delay is caused by the way iOS works, not by the app.
When you switch away from your current app, iOS stops processing the actual interface of the app you were using. What you see on the multitasking screen is a screenshot. When you tap the app's buttons, immediately after opening it, you're actually tapping on a photograph!
Don't believe me? Open the stock Music app and start playing a song. Double tap the home button. Notice that the pink marker on the song progression slider is moving, the time counters running. That's because you didn't go away yet.
Now, with the Music app still running and the song playing, open another app. It doesn't matter what app; Twitter, Calendar, the Camera... any app.
Now, double tap the home button. Look for the Music app card. Look at the pink marker on the song progression bar, the time counters; they're frozen in place! That's because you went away from the app, so iOS took a screenshot, placed it on the card and stopped processing the interface.
Here is where you ask me "But why do other apps work instantly when I go back to them?"
The answer is, again, on the way the system works. There are 2 reasons for this:
1- When you switch back to the app you were using, the system needs to reload the interface of the app.
This happens to ALL apps on the background.
Simpler apps, like WhatsApp, use core resources from the system or really small amounts of custom elements on their interface elements, that's why they load almost instantly. Other apps use custom resources on their UIs, which the system takes longer to load. Apps that have more complex interfaces, like Spotify, have this delay because the system needs to load more data.
Don't think Spotify is evil or bad for having a more complex app. Most apps with complex interfaces use them because they need them. Otherwise, they wouldn't be able to have most of their features, since the standard resources don't cover everything.
2- The system's tendency to suspend apps is bigger the longer they stay on the background.
Have you ever found yourself with a bunch of apps open and when you go back to the first one you opened, quite a while ago, it looks like it's loading itself again? No?
Anyway, when you stop interacting with an app, iOS tends to close it. The more apps you open after switching away from it, how long ago you went away; iOS notices this. Its tendency to close apps is also bigger with apps that put more strain on the system, like the ones with complex interfaces.
That's why there's almost no performance drop or impact on the battery life when you switch between a lot of apps.
When you start multitasking, iOS is like:
"He/She's switching between these two apps constantly, I'll keep them running so the transition between them is instant"
"He/She stopped using that app quite a while ago. I'll close it so the current app he/she is using runs faster and there's enough battery for the day"
"He/She stopped using her/his phone. I'll check which apps she was using and keep them updated with the most recent data, so he/she can catch up quickly with his/her friends when he/she comes back"
I hope this helped you understanding a bit about why you see this delay. Still confused? Let me know!
Staff / Moderator/ 2 years ago in Social & Random