不能在UIImageView+AFNetworking.h中使用Success和Failure块

Question

我试图添加一个成功和错误块来检查图像何时加载，以便我可以使用NSCache来动态调整图像的大小。但当我尝试

[scribbleImage setImageWithURL: [NSURL URLWithString:scribble[@"scribble_image"]] placeholderImage:[UIImage imageNamed:@"Default.png"] success:^(UIImage *image) {
NSLog(@"done");
} failure:^(NSError *error) {
NSLog(@"error %@",error);
}];

Xcode给我一个错误，说No visible @interface for 'UIImageView' declares the selector 'setImageWithURL:placeholderImage:success:failure:'

我不知道为什么。

p。我正在导入UIImageView+AFNetworking.h和事情工作得很好没有成功和失败块

Answer 1

这是因为没有setImageWithURL:placeholderImage:success:failure:方法只有setImageWithURLRequest:placeholderImage:success:failure:

NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:scribble[@"scribble_image"]]];
[scribbleImage setImageWithURLRequest:request placeholderImage:[UIImage imageNamed:@"Default.png"] success:^(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image) {
    NSLog(@"Done");
} failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error) {
    NSLog(@"Failed with error: %@", error);
}];

如果你看看setImageWithURL:placeholderImage:做什么:

- (void)setImageWithURL:(NSURL *)url
       placeholderImage:(UIImage *)placeholderImage
{
    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
    [request setHTTPShouldHandleCookies:NO];
    [request addValue:@"image/*" forHTTPHeaderField:@"Accept"];
    [self setImageWithURLRequest:request placeholderImage:placeholderImage success:nil failure:nil];
}

你可以看到这个方法也是用来获取内部的