objective-c singleton应存储UIimage。


objective-c singleton shall store UIimage. Does not work

我有一个单件的地方，想在单件存储一个UIImage。不知何故，这行不通。我得到编译错误：No visible @interface for 'UIImage' declares the selector 'setPhoto'。有趣的是，我和我的NSMutableArray在单子上工作很好。

如何在我的单例上存储一个UIImage，以便以后从另一个类访问它？

单身汉

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#import <Foundation/Foundation.h>

@interface SingletonClass : NSObject

@property (strong, nonatomic) NSMutableArray *myArray;
@property (strong, nonatomic) UIImage *photo;

+ (id)sharedInstance;
-(void)setPhoto:(UIImage *)photo    

@end

单身汉

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#import"SingletonClass.h"

@implementation SingletonClass

static SingletonClass *sharedInstance = nil;

// Get the shared instance and create it if necessary.
+ (SingletonClass *)sharedInstance {
    if (sharedInstance == nil) {
        sharedInstance = [[super allocWithZone:NULL] init];
    }

    return sharedInstance;
}

// We can still have a regular init method, that will get called the first time the Singleton is used.
- (id)init
{
    self = [super init];

    if (self) {
        // Work your initialising magic here as you normally would
        self.myArray = [[NSMutableArray alloc] init];
        self.photo = [[UIImage alloc] init];
    }

    return self;
}

// We don't want to allocate a new instance, so return the current one.
+ (id)allocWithZone:(NSZone*)zone {
    return [self sharedInstance];
}

// Equally, we don't want to generate multiple copies of the singleton.
- (id)copyWithZone:(NSZone *)zone {
    return self;
}

-(void)setPhoto:(UIImage *)photo {
    photo = _photo;
}

详细视图

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-(void)sharePhoto:(id)sender {

    SingletonClass *sharedSingleton = [SingletonClass sharedInstance];

    [sharedSingleton.photo setPhoto:self.imageView.image];
    //Compiler Error: No visible @interface for 'UIImage' declares the selector 'setPhoto'

    [self.navigationController popViewControllerAnimated:YES];

}
相关讨论

通过调用[sharedSingleton.photo setPhoto:self.imageView.image];，您基本上是这样做的：

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UIImage *theImage = sharedSingleton.photo;
[theImage setPhoto:self.imageView.image];

所以你不是在你的SingletonClass上给setPhoto:打电话，而是在返回的UIImage上打电话。似乎是错的。

你可能想要：[sharedSingleton setPhoto:self.imageView.image];。

然后，我对这个方法有点困惑：

-(空)setphoto：(uiimage*)照片{照片=照片；}

首先，你可能不需要它，因为你有一个@property。然后将参数(photo设置为变量(_photo)。走错路了？

相关讨论

在细节视图中

-(无效)共享照片：(ID)发件人{

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[[SingletonClass sharedInstance] setPhoto:self.imageView.image];
[self.navigationController popViewControllerAnimated:YES];

}

将方法更改为：

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-(void)sharePhoto:(id)sender {
SingletonClass *sharedSingleton = [SingletonClass sharedInstance];
[sharedSingleton setPhoto:self.imageView.image];
//Compiler Error: No visible @interface for 'UIImage' declares the selector 'setPhoto'
[self.navigationController popViewControllerAnimated:YES];

}

使用这一行[sharedSingleton.photo setPhoto:self.imageView.image];，您实际上是在sharedsingleton.photo中查找photo属性，而sharedsingleton.photo实际上并未在其中声明，因此会产生错误。