ios - 为什么我的图像无法写入文件和显示？

Question

我想同时下载、保存和显示图像。

我正在使用这段代码，当我直接加载 *image 时它确实有效。

 [self.imageView setImageWithURLRequest:request placeholderImage:nil
    success:^(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image) {
        // Set the image
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *filePath = [[paths objectAtIndex:0] stringByAppendingPathComponent:@"Image.png"];

        // Save image.
        [UIImagePNGRepresentation(image) writeToFile:filePath atomically:YES];

        UIImage * imag2e = [UIImage imageNamed: @"Image"];
        weakSelf.imageView.image = imag2e;

        [self updateZoom];
        [self updateConstraints];

        [MBProgressHUD hideHUDForView:weakSelf.view animated:YES];
    }
    failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error) {
        NSLog(@"An error occured when loading the image, %@", [error description]);
        [MBProgressHUD hideHUDForView:weakSelf.view animated:YES];
    }];

Answer 1

我觉得错误就在于此:

UIImage * imag2e = [UIImage imageNamed: @"Image"];

在 +[UIImage imageNamed:] 的文档中它指出:

If this is the first time the image is being loaded, the method looks for an image with the specified name in the application’s main bundle.

而保存的图像位于其他地方。例如。尝试:

UIImage * imag2e = [UIImage imageWithContentsOfFile: filePath];