Ios 在后台模式下循环

我想在后台搜索RSSI。我试图通过调用同一个函数中的函数来实现这一点。有没有办法让这个循环在后台模式下运行。在我看来，它应该是生活在背景中，但我在经历了无数次灾难后就死了。如何让它不断搜索

- (void)applicationWillResignActive:(UIApplication *)application
{
    if([[UIDevice currentDevice] respondsToSelector:@selector(isMultitaskingSupported)])
    {
        NSLog(@"Multitasking Supported");
    }
    else
    {
        NSLog(@"Multitasking Not Supported");
    }

    NSLog(@"Start background task");
    mBeaconDeviceList = [[NSMutableArray alloc] init];
    mBeaconConfigManager = [[JLEBeaconConfigManager alloc] init];
    mBeaconConfigManager.delegate = self;
    [mBeaconConfigManager startJaaleeBeaconsDiscovery];
}

#pragma mark - JLEBeaconConfigManager delegate
-(void)beaconConfigManager:(JLEBeaconConfigManager *)manager didDiscoverBeacon:(JLEBeaconDevice *)beacon RSSI:(NSNumber *)RSSI AdvData:(NSDictionary *)AdvData
{
    NSLog(@"Find RSSI");
    if ([RSSI intValue] > 0 || [RSSI intValue] < -40) {
        return;
    }

    if ([mBeaconDeviceList containsObject:beacon]) {
        [mBeaconDeviceList removeObject:beacon];
    }
    [mBeaconDeviceList addObject:beacon];
    NSLog(@"FOUND: %@", RSSI);

    NSLog(@"Start again");
    mBeaconDeviceList = [[NSMutableArray alloc] init];
    mBeaconConfigManager.delegate = self;
    [mBeaconConfigManager startJaaleeBeaconsDiscovery];
}

-（void）应用程序将重新指定：（UIApplication*）应用程序
{
如果（[[UIDevice currentDevice]响应选择器：@selector（isMultitaskingSupported）]）
{
NSLog（@“支持多任务”）；
}
其他的
{
NSLog（@“不支持多任务”）；
}
NSLog（@“启动后台任务”）；
mBeaconDeviceList=[[NSMutableArray alloc]init]；
mBeaconConfigManager=[[JLEBeaconConfigManager alloc]init]；
mBeaconConfigManager.delegate=self；
[MBeAconfigManager启动JaaleebaconsDiscovery]；
}
#pragma标记-jlebaconconfigmanager委托
-（void）BeanConfigmanager:（JLEBeaconConfigManager*）manager didDiscoverBeacon:（JLEBeaconDevice*）信标RSSI:（NSNumber*）RSSI AdvData:（NSDictionary*）AdvData
{
NSLog（“查找RSSI”）；
如果（[RSSI intValue]>0 | |[RSSI intValue]<-40）{
返回；
}
if（[mBeaconDeviceList containsObject:beacon]）{
[mBeaconDeviceList removeObject:beacon]；
}
[mBeaconDeviceList addObject:beacon]；
NSLog（@“发现：%@”，RSSI）；
NSLog（@“重新启动”）；
mBeaconDeviceList=[[NSMutableArray alloc]init]；
mBeaconConfigManager.delegate=self；
[MBeAconfigManager启动JaaleebaconsDiscovery]；
}

您可以将后台时间延长到3分钟，这将使您有更多的时间从RSSIs进行搜索。您可以在ApplicationIdentinterBackground中进行如下扩展：

- (void)extendBackgroundRunningTime {
    if (_backgroundTask != UIBackgroundTaskInvalid) {
        // if we are in here, that means the background task is already running.
        // don't restart it.
        return;
    }
    NSLog(@"Attempting to extend background running time");

    __block Boolean self_terminate = YES;

    _backgroundTask = [[UIApplication sharedApplication] beginBackgroundTaskWithName:@"DummyTask" expirationHandler:^{
        NSLog(@"Background task expired by iOS");
        if (self_terminate) {
            [[UIApplication sharedApplication] endBackgroundTask:_backgroundTask];
            _backgroundTask = UIBackgroundTaskInvalid;
        }
    }];

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        NSLog(@"Background task started");

        while (true) {
            NSLog(@"background time remaining: %8.2f", [UIApplication sharedApplication].backgroundTimeRemaining);
            [NSThread sleepForTimeInterval:1];
        }

    });
}

---

我认为现在时间不是问题。问题是方法

beaconfigmanager

在

applicationwillresignative

调用，但当它转到

applicationidentinterbackground

时，方法

beaconfigmanager

停止发送响应。