Xcode 无法调用方法

我试图使用[self-changeColor]调用下面的方法；得到

@MyClassViewController没有可见接口声明选择器“changeColor”

我在h和m上都是这样声明的：

@interface changeColor 

- (UIImage *) changeColor:(UIImage *)image;

@end

我做错了什么？ 请帮忙

-------------代码-------------

---

问题是

[self-changeColor]；

changeColor

和

changeColor:

是两个不同的东西。如果将其定义为使用一个参数，则必须这样调用

- (UIImage *) changeColor:(UIImage *)image 

{
    UIGraphicsBeginImageContext(image.size);

    CGRect contextRect;
    contextRect.origin.x = 0.0f;
    contextRect.origin.y = 0.0f;
    contextRect.size = [image size];
    // Retrieve source image and begin image context
    CGSize itemImageSize = [image size];
    CGPoint itemImagePosition; 
    itemImagePosition.x = ceilf((contextRect.size.width - itemImageSize.width) / 2);
    itemImagePosition.y = ceilf((contextRect.size.height - itemImageSize.height) );

    UIGraphicsBeginImageContext(contextRect.size);

    CGContextRef c = UIGraphicsGetCurrentContext();
    // Setup shadow
    // Setup transparency layer and clip to mask
    CGContextBeginTransparencyLayer(c, NULL);
    CGContextScaleCTM(c, 1.0, -1.0);
    CGContextClipToMask(c, CGRectMake(itemImagePosition.x, -itemImagePosition.y, itemImageSize.width, -itemImageSize.height), [image CGImage]);

    CGContextSetRGBFillColor(c, 0, 0, 1, 1);

    NSLog(@"--------- METHOD DETECTED");//>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> TEST
    /*
    switch (row)

    {   
        case 0:
            CGContextSetRGBFillColor(c, 0, 0, 1, 1);
            break;

        default:
            CGContextSetRGBFillColor(c, 1, 0, 0., 1);
            break;
    }   
    */

    contextRect.size.height = -contextRect.size.height;
    contextRect.size.height -= 15;
    // Fill and end the transparency layer
    CGContextFillRect(c, contextRect);
    CGContextEndTransparencyLayer(c);

    UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return img;
}