iOS 7 后台获取

Question

我目前正在开发一个 iOS 应用程序，我在其中使用 [[UIApplication sharedApplication] setMinimumBackgroundFetchInterval:UIApplicationBackgroundFetchIntervalMinimum];。根据我以这种方式实现的文档。

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.

    NSLog(@"Launched in background %d", UIApplicationStateBackground == application.applicationState);

    [[UIApplication sharedApplication] setMinimumBackgroundFetchInterval:UIApplicationBackgroundFetchIntervalMinimum];
    i =0;

    return YES;
}


-(void)application:(UIApplication *)application performFetchWithCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler {
    NSLog(@"Fetch started");
    ++i;    

    // Set up Local Notifications
    [[UIApplication sharedApplication] cancelAllLocalNotifications];
    UILocalNotification *localNotification = [[UILocalNotification alloc] init];
    NSDate *now = [NSDate date];
    localNotification.fireDate = now;

    localNotification.soundName = UILocalNotificationDefaultSoundName;
    localNotification.alertBody = @"BG Mode";
    localNotification.applicationIconBadgeNumber = i;

    [[UIApplication sharedApplication] scheduleLocalNotification:localNotification];

    completionHandler(UIBackgroundFetchResultNewData);
    NSLog(@"Fetch completed");
}

我的问题是我尝试调试它以了解此方法调用的频率。我没有得到任何澄清。我已经用 timeinterval 60 秒进行了测试，但这也不起作用。请给我任何想法或建议。提前致谢。

Answer 1

澄清一下，您还根据 Apple 的文档在 Info.plist 中设置了 UIBackgroundModes ...

This property has no effect for apps that do not have the UIBackgroundModes key with the fetch value in its Info.plist file.