不断检查在ios中启用的位置服务

Question

我试图制作一个应用程序，其中视图将检查位置服务是否已启用。如果未启用，则会弹出一个提示，但仍会继续搜索位置，但不会提示。一旦定位服务启用，它将继续其过程。

如何做到这一点???

Answer 1

您可以通过这个代码查询位置服务的可用性：

MKUserLocation *userLocation = map.userLocation; 
    BOOL locationAllowed = [CLLocationManager locationServicesEnabled]; 
    BOOL locationAvailable = userLocation.location!=nil; 

    if (locationAllowed==NO) { 
     UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Location Service Disabled" 
                 message:@"To re-enable, please go to Settings and turn on Location Service for this app." 
                 delegate:nil 
               cancelButtonTitle:@"OK" 
               otherButtonTitles:nil]; 
     [alert show]; 
     [alert release]; 
    } else { 
     if (locationAvailable==NO) 
      [self.map.userLocation addObserver:self forKeyPath:@"location" options:(NSKeyValueObservingOptionNew|NSKeyValueObservingOptionOld) context:nil]; 
    } 

Answer 2

添加在.h文件中INT计数器;

在你看来的viewDidLoad方法添加这个，因为它会检查每一秒ü可以增加计数器：

[NSTimer scheduledTimerWithTimeInterval:1.0  
          target:self 
          selector:@selector(checkLocationMangerEnabled:)  
          userInfo:nil  
          repeats:YES]; 

counter = 0; 

现在选择应该是：

-(void)checkLocationMangerEnabled:(id)sender 
{ 
    if([CLLocationManager locationServicesEnabled]) 
    { 
     //here location is enabled 
    } 
    else 
    { //Not enabled 
    if(counter == 60) // alert will showed in every 1 min u can increase or decrese 
    { 
     UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Location Service Disabled" 
                message:@"To re-enable, please go to Settings and turn on Location Service for this app." 
                delegate:nil 
              cancelButtonTitle:@"OK" 
              otherButtonTitles:nil]; 
     [alert show]; 
     [alert release]; 
    } 
    counter++; 
    } 
} 

Answer 3

你不能继续获得，如果位置的位置服务被禁用。

如果要继续检查

[CLLocationManager locationServicesEnabled] 

如果启用搜索位置确保该服务允许，开始更新位置

[locationManager startUpdatingLocation]; 

然后在

- (void)locationManager:(CLLocationManager *)manager 
    didUpdateToLocation:(CLLocation *)newLocation 
      fromLocation:(CLLocation *)oldLocation { 
    [locationManager stopUpdatingLocation]; // This will stop to check the location 
} 

删除此代码仍然检查位置[locationManager stopUpdatingLocation];，但这不是t他最好的办法，一定要阅读apple documentation for the policy of getting the location