アプリにバックグラウンド タスクを実装しようとしています。実装する前に、以下に示すように簡単な例を挙げたいと思いました。カウンターを置いただけで、それがカウントされるかどうかを確認したいと思います。ただし、プロセスと呼ばれる私のメソッドは起動しません。私は何が欠けているのだろうか。
- (void)applicationDidEnterBackground:(UIApplication *)application
{
if ([[UIDevice currentDevice] respondsToSelector:@selector(isMultitaskingSupported)]) { //Check if our iOS version supports multitasking I.E iOS 4
if ([[UIDevice currentDevice] isMultitaskingSupported]) { //Check if device supports mulitasking
UIApplication *application = [UIApplication sharedApplication]; //Get the shared application instance
__block UIBackgroundTaskIdentifier background_task; //Create a task object
background_task = [application beginBackgroundTaskWithExpirationHandler: ^ {
[application endBackgroundTask: background_task]; //Tell the system that we are done with the tasks
background_task = UIBackgroundTaskInvalid; //Set the task to be invalid
//System will be shutting down the app at any point in time now
}];
//Background tasks require you to use asyncrous tasks
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
//Perform your tasks that your application requires
NSLog(@"\n\nRunning in the background!\n\n");
pollingTimer2 = [NSTimer scheduledTimerWithTimeInterval:0.1
target:self
selector:@selector(process)
userInfo:nil
repeats:YES];
[application endBackgroundTask: background_task]; //End the task so the system knows that you are done with what you need to perform
background_task = UIBackgroundTaskInvalid; //Invalidate the background_task
});
}
}
}
-(void) process
{
county= county+1;
NSLog(@"%d,county",county);
}