Continued solution after nstimer enters the background

1. In info. plist, add the required background modes key. The value is app plays audio.

2. Declare the code in the program startup method (-(bool) Application: didfinishlaunchingwitexceptions :)

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];    // Override point for customization after application launch.    <span style="color:#FF6666;">NSError *setCategoryErr = nil;    NSError *activationErr  = nil;    [[AVAudioSession sharedInstance]     setCategory: AVAudioSessionCategoryPlayback     error: &setCategoryErr];    [[AVAudioSession sharedInstance]     setActive: YES     error: &activationErr];</span>    self.window.backgroundColor = [UIColor whiteColor];    [self.window makeKeyAndVisible];    return YES;}

3. Add the following code to the-(void) applicationdidenterbackground :( uiapplication *) application function in the appdelegate file, or add the notification method after the application registered in a specific class enters the background.

- (void)applicationDidEnterBackground:(UIApplication *)application{     UIApplication*   app = [UIApplication sharedApplication];    __block    UIBackgroundTaskIdentifier bgTask;    bgTask = [app beginBackgroundTaskWithExpirationHandler:^{        dispatch_async(dispatch_get_main_queue(), ^{            if (bgTask != UIBackgroundTaskInvalid)            {                bgTask = UIBackgroundTaskInvalid;            }        });    }];    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{        dispatch_async(dispatch_get_main_queue(), ^{            if (bgTask != UIBackgroundTaskInvalid)            {                bgTask = UIBackgroundTaskInvalid;            }        });    });

Thank you for your criticism!

Continued solution after nstimer enters the background