Question

我正在尝试将UIImage子类化，因此我可以为每个图像添加一个特殊的标题和其他信息。下面是我的.m：

#import "Sticker.h"

@implementation Sticker



//custom init
-(instancetype)initWithTitle: (NSString *)title neededCount: (int)neededCount specialMesage: (NSString *)specialMesage andFilename: (NSString *)path {

    self = [super initWithContentsOfFile:path];

    if(self) {

        self.title=title;
        self.neededCount=neededCount;
        self.specialMessage=specialMessage;


    }

    return self;



}

我有一个带有单个UIImageView的空视图控制器，我正在尝试创建一个新的贴纸对象并使用UIImageView中的图像。代码：

Sticker *sticker = [[Sticker alloc] initWithTitle:@"crazy clown" neededCount:50 specialMessage:@"stackoverflow" andFilename:@"clown"];
    self.imageView.image=sticker;
    self.imageView.hidden=NO;

由于某种原因，图像未显示且没有错误消息。＆＃34;小丑＆＃34;是Images.xcassets中的pdf图像。谁能给我一些指示，告诉我为什么这不起作用？

Answer 1

您不应该为此尝试创建一个具有UIImage属性的类来为UIImage创建子类。

@interface Sticker : NSObject
@property (strong, nonatomic) NSString *title;
@property (assign, nonatomic) int neededCount;
@property (strong, nonatomic) NSString *specialMessage;
@property (strong, nonatomic) UIImage *image;

-(instancetype)initWithTitle:(NSString *)title neededCount:(int)neededCount specialMesage:(NSString *)specialMessage filename:(NSString *)name;

@end

@implementation Sticker

-(instancetype)initWithTitle:(NSString *)title neededCount:(int)neededCount specialMesage:(NSString *)specialMessage filename:(NSString *)name {
    if(self = [super init]) {
        self.title = title;
        self.neededCount = neededCount;
        self.specialMessage = specialMessage;
        self.image = [UIImage imageNamed:name];
    }
    return self;
}

@end

Sticker *sticker = [[Sticker alloc] initWithTitle:@"crazy clown" neededCount:50 specialMessage:@"stackoverflow" filename:@"clown"];
self.imageView.image = sticker.image;

无论如何initWithContentsOfFile需要一个完整的路径而不仅仅是文件名。

Answer 2

子类化UIImage有点时髦。但它可以做到

class PlaceHolderIcon: UIImage {

    override init() {
        let image = UIImage(named: "image-name")!
        super.init(cgImage: image.cgImage!, scale: UIScreen.main.scale, orientation: .up)
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    required convenience init(imageLiteralResourceName name: String) {
        fatalError("init(imageLiteralResourceName:) has not been implemented")
    }

}

尝试子类化UIImage但图像未在图像视图中显示

2 个答案: