可能很容易修复：无效的参数类型＆＃39; void＆＃39;一元的表达

Question

我是Objective C的新手，并试图在Xcode中创建一个基本的地图应用程序。我一直在(void)mapView方法

上收到此错误

Invalid argument type 'void' to unary expression 

这是我的代码，

- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
self.mapView.delegate = self;
}

//H+ adding to have scale adjusted
- (void)mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation
{
    MKCoordinateRegion region = MKCoordinateRegionMakeWithDistance(userLocation.coordinate, 800, 800);
    [self.mapView setRegion:[self.mapView regionThatFits:region] animated:YES];

}

造成这种情况的原因是什么？

Answer 1

您在}功能上错过了右括号（viewDidLoad）。更正后，它应如下所示（请参阅THIS!!!注释的行）：

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    self.mapView.delegate = self;
} // <-- THIS!!!

//H+ adding to have scale adjusted
- (void)mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation
{
    MKCoordinateRegion region = MKCoordinateRegionMakeWithDistance(userLocation.coordinate, 800, 800);
    [self.mapView setRegion:[self.mapView regionThatFits:region] animated:YES];
}

由于缺少大括号，编译器认为您的mapView:didUpdateUserLocation函数定义是viewDidLoad函数中的表达式，而不是函数定义。我猜这可能不是你想要的。