iOS8什么时候分配init CLLocationManager来调用requestWhenInUseAuthorization？

Question

当我尝试在它的getter中分配init我的CLLocationManager时，我没有得到位置自动化的弹出请求。但是，当我放入viewDidLoad时，它确实有效。

我的代码看起来像这样：

- (void)viewDidLoad {
    [super viewDidLoad];
    self.mapView.delegate = self;
    self.locationManager = [[CLLocationManager alloc] init]; //when i put this here it works
    self.locationManager.delegate = self;
    CLAuthorizationStatus status = [CLLocationManager authorizationStatus];
    if(![CLLocationManager authorizationStatus])
    {
        [self.locationManager requestWhenInUseAuthorization];
    }
    self.mapView.showsUserLocation = YES;
    [self.mapView setMapType:MKMapTypeStandard];
    [self.mapView setZoomEnabled:YES];
    [self.mapView setScrollEnabled:YES];
}

但是当我像这样执行alloc init时它不起作用：

-(CLLocationManager *)locationManager
{
    if(_locationManager) _locationManager = [[CLLocationManager alloc]init];
    return _locationManager;
}

任何人都可以向我解释为什么会这样吗？

Answer 1

因为您的访问者方法中存在逻辑错误：

- (CLLocationManager *)locationManager
{
    if(_locationManager == nil) _locationManager = [[CLLocationManager alloc] init];
    return _locationManager;
}