iOS后台进程

Question

我需要在我的应用程序运行时与服务器进行同步。 有时，这种同步可能需要几分钟。 在 iPhone 上，如果用户按下主页按钮或设备自动锁定，则此任务会中断。

我试过类似的东西：

backgroundTaskID = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{
            [[UIApplication sharedApplication] endBackgroundTask:backgroundTaskID];
            backgroundTaskID = UIBackgroundTaskInvalid;
    }];
[self Synchronization];

funcao sincronização:

-(void)Synchronization{

    object=nil;

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        [TheAppDelegate setSync:YES];

        send = NO;
        responseObj = [[ConteinerInicial alloc] init];
        object = [self fillObjectContainer:1];

        error = NO;

        [[objectManager HTTPClient] setDefaultHeader:@"Token" value:TheAppDelegate.token.token];
        [[objectManager HTTPClient] setDefaultHeader:@"Username" value:TheAppDelegate.token.userName];
        [[objectManager HTTPClient] setDefaultHeader:@"IDDevice" value:TheAppDelegate.token.IDDevice];

        [objectManager postObject:object path:@"" parameters:nil success:^(RKObjectRequestOperation *operation, RKMappingResult *result){
            NSArray *response = [result array];
            NSLog(@"Loading mapping result: %@", result);

            NSDictionary *headerDictionary = [operation.HTTPRequestOperation.response allHeaderFields];
            NSString *authenticationStatus = [headerDictionary objectForKey:@"AuthenticationStatus"];

            // if server returns "NotAuthorized", user must login again
            if ([authenticationStatus isEqualToString:@"NotAuthorized"]) {
                [AppDelegate showErrorAlert:@"Login expired!"];
                [TheAppDelegate clearLoginToken];
                error = YES;
                return;
            }

            responseObj = [response objectAtIndex:0];

            if(responseObj.Package.count>0)
            {
                [self savePackage:responseObj tipo:1];
                [self Synchronization];
            }else
            {
                [[UIApplication sharedApplication] endBackgroundTask:backgroundTaskID];
                backgroundTaskID = UIBackgroundTaskInvalid;
            }

        } failure: ^(RKObjectRequestOperation *operation, NSError *reportError){
            RKLogError(@"Operation failed with error: %@", reportError);
            [AppDelegate showErrorAlert:@"There is some problem with the connection or the server! Please, check your connection or the address of the server and try again."];
            send = YES;
            [TheAppDelegate setSync:NO];
            error = YES;
        }];

    });
}

并且在同步结束时准备好了：

[[UIApplication sharedApplication] endBackgroundTask:backgroundTaskID];
                backgroundTaskID = UIBackgroundTaskInvalid;

但是这段代码不起作用，有人知道我该如何克服这个挑战吗？

同步的方式是请求数据直到不再存在。但是使用此代码，它最终会出现在进入后台时正在接收的背景对象中

Answer 1

您的代码在到期处理程序中调用[self synchronization];。仅当您的应用程序没有时间在后台运行时才会调用该块。因此，您仅在没有时间进行同步时才尝试开始同步。

在街区外致电[self synchronization];。该块应包含清理/暂停代码并结束后台任务...

另外，请考虑使用 NSURLSession 以获得良好的 iOS 7 兼容性。