iOS/Xcode：与之后打开已安装的应用程序相比，在连接到 Xcode 的情况下在 iPhone 上运行应用程序有区别吗？

Question

I have a Timer which plays AVAudio at a specific time while the screen is locked (app in foreground when locked and plist setting 'Application does not run in background' set to YES).

When I run my code while my iPhone is connected to Xcode it works as desired, playing audio while locked even when the iPhone has been locked for hours.

Now if I disconnect my iPhone and just open the app by tapping the icon the audio won't be played if it's set for more than a minute.

Is there a difference that causes this problem? If I would publish my App to the AppStore which behaviour would my users get?

Answer 1

That 'Application does not run in background' flag is a very old flag that means your app does not support multitasking and should be terminated when the user presses the home button. There's no good reason I can think of to set that flag on a newly developed application. Unless you understand exactly what it's for and are positive that setting it to yes is the correct thing to do, don't do that.

(That flag was added when iOS 4 was released, to allow apps that could not handle multi-tasking to request the old terminate-on-home-button behavior from iOS 3. Given that we're now 6 major iOS releases from iOS 4, it seems outdated.)

So remove that flag. It probably doesn't have any impact on your question, but remove it or set it to no in any case.

If you want to run a timer while the phone is locked and play sounds at designated times then you will probably need to set your app up as a background sound player, and ask for more background time when you get a message that you are going to the background.

That being said it's likely that Apple will reject your app. Running a timer from the background means that the processor on the phone has to run at full speed all the time, which will DRAMATICALLY reduce battery life.

Apple only allows a very small subset of apps to run in the background, and then only under specific circumstances (like a background sound playing app when the user is actively listening to music, or a navigation app that is actively tracking the user's location and notifying them when it's time to make a turn to follow directions.)

Answer 2

Should be no different. If you'd like to feel what do your users' feel then you can publish it to TestFlight which is the best app beta test environment. Find some testers or try it yourself. The directions should be to verify the playing logic and the sound file relationship which link to the connection.