iOS常駐后臺
1、步驟一：在Info.plist中，添加"Required background modes"鍵，value為：App plays audio
步驟二：
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window=[[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];//Override point for customization after application launch.NSError *setCategoryErr =nil;
NSError*activationErr? =nil;
[[AVAudioSession sharedInstance]
setCategory: AVAudioSessionCategoryPlayback
error:&setCategoryErr];
[[AVAudioSession sharedInstance]
setActive: YES
error:&activationErr];
self.window.backgroundColor=[UIColor whiteColor];
[self.window makeKeyAndVisible];returnYES;
}
步驟三：將以下代碼添加到appDelegate文件中的- (void)applicationDidEnterBackground:(UIApplication *)application函數，也可添加到在具體類中注冊的應用進入后臺后的通知方法
- (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;
}
});
});
}
完成以上步驟你會發現，程序進入后臺后仍可運行定時器！
