Iphone 未知类型名称'；TransportViewController'；

这可能是一个简单的错误，但我似乎无法找出错误的原因

未知类型名称“TransportViewController”

。我正在尝试将xCoor和yCoor（2

double

值）传递给我的第二个视图，即TransportViewController。这是我的密码：

TransportViewController *xCoor;
TransportViewController *yCoor;
@property (retain, nonatomic) TransportViewController *xCoor;
@property (retain, nonatomic) TransportViewController *yCoor;

这4行给了我一个错误

MapViewController.h文件

#import "TransportViewController.h"
@interface MapViewController : UIViewController{
    TransportViewController *xCoor;
    TransportViewController *yCoor;
}
@property (retain, nonatomic) TransportViewController *xCoor;
@property (retain, nonatomic) TransportViewController *yCoor;

#import "TransportViewController.h"
@implementation MapViewController
@synthesize xCoor;
@synthesize yCoor;
.
.
.
- (IBAction) publicTransportAction:(id)sender{
    TransportViewController *view = [[TransportViewController alloc] initWithNibName:nil bundle:nil];
    self.xCoor = view;
    self.yCoor = view;
    xCoor.xGPSCoordinate = self.mapView.gps.currentPoint.x;
    yCoor.xGPSCoordinate = self.mapView.gps.currentPoint.y;
    [self presentModalViewController:view animated:NO];
}

#import "MapViewController.h"
@interface TransportViewController : UIViewController<UITextFieldDelegate>
{
    double xGPSCoordinate;
    double yGPSCoordinate;
}
@property(nonatomic)double xGPSCoordinate;
@property(nonatomic)double yGPSCoordinate;
@end

MapViewController.m文件

#import "TransportViewController.h"
@interface MapViewController : UIViewController{
    TransportViewController *xCoor;
    TransportViewController *yCoor;
}
@property (retain, nonatomic) TransportViewController *xCoor;
@property (retain, nonatomic) TransportViewController *yCoor;

#import "TransportViewController.h"
@implementation MapViewController
@synthesize xCoor;
@synthesize yCoor;
.
.
.
- (IBAction) publicTransportAction:(id)sender{
    TransportViewController *view = [[TransportViewController alloc] initWithNibName:nil bundle:nil];
    self.xCoor = view;
    self.yCoor = view;
    xCoor.xGPSCoordinate = self.mapView.gps.currentPoint.x;
    yCoor.xGPSCoordinate = self.mapView.gps.currentPoint.y;
    [self presentModalViewController:view animated:NO];
}

#import "MapViewController.h"
@interface TransportViewController : UIViewController<UITextFieldDelegate>
{
    double xGPSCoordinate;
    double yGPSCoordinate;
}
@property(nonatomic)double xGPSCoordinate;
@property(nonatomic)double yGPSCoordinate;
@end

TransportViewController.h文件

#import "TransportViewController.h"
@interface MapViewController : UIViewController{
    TransportViewController *xCoor;
    TransportViewController *yCoor;
}
@property (retain, nonatomic) TransportViewController *xCoor;
@property (retain, nonatomic) TransportViewController *yCoor;

#import "TransportViewController.h"
@implementation MapViewController
@synthesize xCoor;
@synthesize yCoor;
.
.
.
- (IBAction) publicTransportAction:(id)sender{
    TransportViewController *view = [[TransportViewController alloc] initWithNibName:nil bundle:nil];
    self.xCoor = view;
    self.yCoor = view;
    xCoor.xGPSCoordinate = self.mapView.gps.currentPoint.x;
    yCoor.xGPSCoordinate = self.mapView.gps.currentPoint.y;
    [self presentModalViewController:view animated:NO];
}

#import "MapViewController.h"
@interface TransportViewController : UIViewController<UITextFieldDelegate>
{
    double xGPSCoordinate;
    double yGPSCoordinate;
}
@property(nonatomic)double xGPSCoordinate;
@property(nonatomic)double yGPSCoordinate;
@end

#导入“MapViewController.h”
@接口TransportViewController:UIViewController
{
双xgps坐标；
双余弦坐标；
}
@性质（非原子）双Xgps坐标；
@性质（非原子）双余弦坐标；
@结束

您有一个循环依赖项。简而言之，您已指示编译器：

• MapViewController.h

  需要

  TransportViewController.h

• 和

  TransportViewController.h

  需要

  MapViewController.h

实际上，这两种方法在标题中都不是必需的。在这两种情况下都可以使用转发声明

MapViewController.h

@class TransportViewController; // << forward declaration instead of inclusion

@interface MapViewController : UIViewController {
    TransportViewController *xCoor;
    TransportViewController *yCoor;
}
@property (retain, nonatomic) TransportViewController *xCoor;
@property (retain, nonatomic) TransportViewController *yCoor;
@end

@class MapViewController; // << not even needed, as MapViewController
                          //    does not exist in this header

@interface TransportViewController : UIViewController<UITextFieldDelegate>
{
    double xGPSCoordinate;
    double yGPSCoordinate;
}
@property(nonatomic)double xGPSCoordinate;
@property(nonatomic)double yGPSCoordinate;
@end

---

@class TransportViewController；//感谢您的帮助和建议：）但是对于TransportViewController.h
@class MapViewController是必需的，因为我只在这里粘贴了部分代码。