iphone - Objective-C 类别导致无法识别的选择器

Question

我的项目有一个我想从另一个类调用的 UIImage 类别函数。我正确地导入了图像类别的头文件，并且我可以编译项目而没有任何警告。

问题是，当我调用 UIImage 类别函数时，我看到了一个无法识别的选择器错误，并带有 NSInvalidArgumentException。如果我已正确链接所有内容，为什么会看到此内容？

#import <UIKit/UIKit.h>

@interface UIImage (DRShare)

+ (UIImage*) imageNamed:(NSString*)name;

@end


@implementation UIImage (DRShare)

+ (UIImage*) imageNamedDR:(NSString*)name{

    CGFloat s = 1.0f;
    if([[UIScreen mainScreen] respondsToSelector:@selector(scale)]){
        s = [[UIScreen mainScreen] scale];
    }

    NSString *path = [NSString stringWithFormat:@"%@%@%@.png",kImagesPath,name,s > 1 ? @"@2x":@""];
    return [UIImage imageWithContentsOfFile:DRBUNDLE(path)];
}

@end

调用它的文件:

        backgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamedDR:@"Share Popup Background"]];

引发异常:

2010-10-22 11:51:02.880 Stuff[11432:207] +[UIImage imageNamedDR:]: unrecognized selector sent to class 0x1f8e938
2010-10-22 11:51:02.883 Stuff[11432:207] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '+[UIImage imageNamedDR:]: unrecognized selector sent to class 0x1f8e938'
*** Call stack at first throw:
(
    0   CoreFoundation                      0x02e65b99 __exceptionPreprocess + 185
    1   libobjc.A.dylib                     0x02fb540e objc_exception_throw + 47
    2   CoreFoundation                      0x02e6776b +[NSObject(NSObject) doesNotRecognizeSelector:] + 187
    3   CoreFoundation                      0x02dd72b6 ___forwarding___ + 966
    4   CoreFoundation                      0x02dd6e72 _CF_forwarding_prep_0 + 50
    5   TapTapShare                         0x0001291c -[DRShareViewController backgroundView] + 127
    6   TapTapShare                         0x00012343 -[DRShareViewController loadView] + 639
    7   UIKit                               0x0044f54f -[UIViewController view] + 56
    8   UIKit                               0x0044d9f4 -[UIViewController contentScrollView] + 42
    9   UIKit                               0x0045d7e2 -[UINavigationController _computeAndApplyScrollContentInsetDeltaForViewController:] + 48
    10  UIKit                               0x0045bea3 -[UINavigationController _layoutViewController:] + 43
    11  UIKit                               0x0045d12d -[UINavigationController _startTransition:fromViewController:toViewController:] + 524
    12  UIKit                               0x00457ccd -[UINavigationController _startDeferredTransitionIfNeeded] + 266
    13  UIKit                               0x00574b55 -[UILayoutContainerView layoutSubviews] + 226
    14  QuartzCore                          0x02616481 -[CALayer layoutSublayers] + 177
    15  QuartzCore                          0x026161b1 CALayerLayoutIfNeeded + 220
    16  QuartzCore                          0x026160bd -[CALayer layoutIfNeeded] + 111

Answer 1

几种可能性:

1. 您没有将 UIImage+TTShare.m 链接到您的目标。因此，当您拥有 header 时，您并没有编译实现。
2. 如果这是静态库的一部分，您需要将 -all_load 添加到 Other Linker Flags build设置，以便应用链接到该库。