How do I wake up with an app before exiting the app?

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The SDK does not provide a way to terminate the application.

To terminate the application, the only way Apple recommends is to press Homebutton.

But the foundation framework integrates the Darwin framework so that we can use the C function exit (0) to terminate application.

The OpenURL method for UIApplication is another way to exit the application.

When you call the OpenURL method in your code, your app's process is terminated (suspended), and an app is awakened.

Of course, the two exit app mechanism and finally effect is not the same.

When you exit the program using exit (0), your app doesn't just exit the foreground and the memory used by the program is cleared-it's unrecoverable.

Assuming again launch this app,ios will again read the binary from disk-this is a brand new app image.

OpenURL are different. It just hangs up your program, which is recoverable.

Your app exits from the foreground but still exists in the background.

The user is able to "wake" it at some point, and your app is back, and the state of the application still wakes up.

Of course, if your luck is not good, iOS will completely recycle your app from memory,

As the exit (0) did. This is usually the time when system memory is tight.

These two methods may need to coexist at some point.

For example, we want to before the app exits. Wake up with an app. For example, Safari.

At the same time we want our app to be the real "exit" and reclaim all of the app's memory.

This is a "paradox". Because regardless of exit (0) or OpenURL, the operating system terminates the running of the process once it has been run.

Just run any of the statements in both. Another statement cannot be run-because the process has been terminated.

But in some cases, the smart use of the iOS multitasking mechanism. This paradox is true.

For example, we can use the following O-C code to achieve this purpose:

[Self performselector: @selector (Exitapp) Withobject:nil afterdelay:0.5];

[[UIApplication Sharedapplication]openurl:

[nsurlurlwithstring:@ "appscheme://"];

The Exitapp method is actually a code exit (0).

So they both coexist.

First of all. We let exit (0) delay for 0.5 seconds before running, but before that OpenURL of course ran out.

The Performselector:afterdelay method dispatches a task to run after a certain time.

Of course, this time cannot be too long, ".

Since iOS agrees that the app still has a "live" time after entering the background, the time is not too long,

This means that after the OpenURL method is running, the app is still alive and has the opportunity to run the scheduled task (that is, exit (0)).

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How do I wake up with an app before exiting the app?