添加UIImagePickerController时发出警告

Question

我想添加一个UIImagePickerController,我得到一个incompatible type 'id<UINavigationControllerDelegate,UIImagePickerControllerDelegate>'编译器警告.我需要知道为什么？并为它解决方案.

.M

imagePicker = [[UIImagePickerController alloc] init];
[imagePicker setDelegate:self];

.H

@interface GobblesViewController : UIViewController <UIImagePickerControllerDelegate>
{
  UIImagePickerController *imagePicker;
}
@property (nonatomic,strong)UIImagePickerController *imagePicker;

警告点 [imagePicker setDelegate:self];和我不知道为什么会发生这种情况.

Answer 1

你得到这个警告,因为对象,self在这种情况下,您传递中UIImagePickerController的delegate财产,不符合UIImagePickerControllerDelegate 和 UINavigationControllerDelegate协议.这是因为UIImagePickerController它的子类UINavigationController已经声明了它自己的子类delegate.

该delegate属性UIImagePickerController定义为:

@property (nonatomic, assign) id <UINavigationControllerDelegate, UIImagePickerControllerDelegate> delegate;

这意味着它预期任何符合这两个协议的对象.

@interface你班上的宣言应该......

@interface GobblesViewController : UIViewController <UIImagePickerControllerDelegate, UINavigationControllerDelegate>