小编val*_*ine的帖子

我对这个话题非常头疼.我正在开发一个需要定期轮询网络服务器的应用程序,以便检查新数据.根据返回的信息,我希望将本地通知推送给用户.

我知道这种方法与Apple描述的方法略有不同,其中远程服务器根据APNS进行工作,推送远程通知.但是,我有很多理由不能考虑这种方法.一个是用户身份验证机制.出于安全原因,远程服务器无法考虑用户凭据.我所能做的就是将登录和获取核心移动到客户端(iPhone).

我注意到Apple提供了一个应用程序唤醒并保持打开Socket连接(即VoIP应用程序)的机会.

所以,我开始以这种方式进行调查.在plist中添加了所需的信息,我能够在我的appDelegate中使用类似的东西"唤醒"我的应用程序:

[[UIApplication sharedApplication] setKeepAliveTimeout:1200 handler:^{ 
    NSLog(@"startingKeepAliveTimeout");
    [self contentViewLog:@"startingKeepAliveTimeout"];
    MyPushOperation *op = [[MyPushOperation alloc] initWithNotificationFlag:0 andDataSource:nil];
    [queue addOperation:op];
    [op release];
}];

NSOperation然后使用以下块代码启动后台任务:

#pragma mark SyncRequests
-(void) main {
    NSLog(@"startSyncRequest");
    [self contentViewLog:@"startSyncRequest"];
    bgTask = [app beginBackgroundTaskWithExpirationHandler:^{ 
        NSLog(@"exipiration handler triggered");
        [app endBackgroundTask:bgTask];
        bgTask = UIBackgroundTaskInvalid;
        [self cancel];
    }];


        dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
            NSMutableURLRequest *anURLRequest;
            NSURLResponse *outResponse;
            NSError *exitError;
            NSString *username;
            NSString *password;

            NSLog(@"FirstLogin");
            anURLRequest = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:[NSString stringWithFormat:webserverLogin, username, password]]];
            [anURLRequest setHTTPMethod:@"GET"];
            [anURLRequest setTimeoutInterval:120.00];
            [anURLRequest setCachePolicy:NSURLRequestReloadIgnoringCacheData];

            exitError = nil;
            NSData …

我正面临一个问题,没有任何解决方案(还).在用户按下Home按钮后,我正在使用后台任务处理程序来启动一些数据获取.代码类似于:

-(void)startRequest {
    UIApplication *app = [UIApplication sharedApplication];
    bgTask = [app beginBackgroundTaskWithExpirationHandler:^{ 
        dispatch_async(dispatch_get_main_queue(), ^{
                [app endBackgroundTask:bgTask];
                bgTask = UIBackgroundTaskInvalid;
            });
    }];
    //..
    //Fetch data with NSURLRequest / delegate method
    //..
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
    if ([delegate respondsToSelector:delegateErrorMethod])
        [delegate performSelector:delegateErrorMethod];

    UIApplication *app = [UIApplication sharedApplication];
    if (bgTask != UIBackgroundTaskInvalid) {
       dispatch_async(dispatch_get_main_queue(), ^{
            [app endBackgroundTask:bgTask];
            bgTask = UIBackgroundTaskInvalid;
        });
    }
}


- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    if([delegate respondsToSelector:delegateMethod])
        [delegate performSelector:delegateMethod withObject:self];  

    UIApplication *app = [UIApplication sharedApplication];
    if (bgTask != UIBackgroundTaskInvalid) …