在 xcode 中，如何调用返回值的类方法？
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In xcode, how to call a class method which returns a value?
提问by Rian Smith
I'm new to Objective-C and for the life of me cannot get past the error, "no class method for selector"
我是 Objective-C 的新手，我一生都无法克服错误，“没有选择器的类方法”
Here is my .h code:
这是我的 .h 代码：
#import <UIKit/UIKit.h>
@interface PhotoCapViewController : UIViewController < UIImagePickerControllerDelegate, UINavigationControllerDelegate > {
UIImageView * imageView;
UIButton * choosePhotoBtn;
UIButton * takePhotoBtn;
}
@property (nonatomic, retain) IBOutlet UIImageView * imageView;
@property (nonatomic, retain) IBOutlet UIButton * choosePhotoBtn;
@property (nonatomic, retain) IBOutlet UIButton * takePhotoBtn;
- (IBAction)getPhoto:(id)sender;
+ (UIImage *)burnTextIntoImage:(NSString *)text :(UIImage *)img;
@end
Here is the function I have defined in .m
这是我在 .m 中定义的函数
+ (UIImage *)burnTextIntoImage:(NSString *)text :(UIImage *)img {
...
return theImage;
}
Here is how I'm calling the function
这是我调用函数的方式
UIImage* image1 = [PhotoCapViewController burnTextIntoImagetext:text1 img:imageView.image];
Any help would would be appreciated. Thanks.
任何帮助将不胜感激。谢谢。
回答by jrturton
The method you are calling doesn't match the definition.
您调用的方法与定义不匹配。
The definition is this:
定义是这样的：
+ (UIImage *)burnTextIntoImage:(NSString *)text :(UIImage *)img;
so the method name is this:
所以方法名称是这样的：
burnTextIntoImage::
But you call it like this:
但是你这样称呼它：
UIImage* image1 = [PhotoCapViewController burnTextIntoImagetext:text1 img:imageView.image];
so you're trying to call a method named this:
所以你试图调用一个名为 this 的方法：
burnTextIntoImagetext::
You could call it correctly like this:
你可以像这样正确地调用它：
UIImage* image1 = [PhotoCapViewController burnTextIntoImage:text1 :imageView.image];
Though really, your method should be called burnText:(NSString*)text intoImage:(UIImage*)image, so it makes more of a "sentence", like this:
虽然实际上，您的方法应该被调用burnText:(NSString*)text intoImage:(UIImage*)image，因此它更像是一个“句子”，如下所示：
+ (UIImage *)burnText:(NSString *)text intoImage:(UIImage *)image;
...
UIImage *image1 = [PhotoCapViewController burnText:text1 intoImage:imageView.image];
回答by Desdenova
Your method declaration is incomplete.
您的方法声明不完整。
Change
改变
+ (UIImage *)burnTextIntoImage:(NSString *)text :(UIImage *)img;
to
到
+ (UIImage *)burnTextIntoImage:(NSString *)text img:(UIImage *)img;
回答by Neo
Your calling code is wrong, try to use this code
您的调用代码有误，请尝试使用此代码
UIImage* image = [PhotoCapViewController burnTextIntoImage:text1 img:imageView.image];
