UIImagePickerController 保存到磁盘然后加载到 UIImageView

我有一个 UIImagePickerController 将图像以 png 格式保存到磁盘。当我尝试加载 PNG 并设置 UIImageView 时imageView.image到该文件，它不显示。

这是我的代码：

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
    UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];
    NSData *imageData = UIImagePNGRepresentation(image);

    // Create a file name for the image
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setTimeStyle:NSDateFormatterShortStyle];
    [dateFormatter setDateStyle:NSDateFormatterShortStyle];
    NSString *imageName = [NSString stringWithFormat:@"photo-%@.png",
                           [dateFormatter stringFromDate:[NSDate date]]];
    [dateFormatter release];

    // Find the path to the documents directory
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];

    // Now we get the full path to the file
    NSString *fullPathToFile = [documentsDirectory stringByAppendingPathComponent:imageName];

    // Write out the data.
    [imageData writeToFile:fullPathToFile atomically:NO];

    // Set the managedObject's imageLocation attribute and save the managed object context
    [self.managedObject setValue:fullPathToFile forKey:@"imageLocation"];
    NSError *error = nil;
    [[self.managedObject managedObjectContext] save:&error];


    [self dismissModalViewControllerAnimated:YES];
}

然后这是我尝试加载它的方法：

self.imageView.backgroundColor = [UIColor lightGrayColor];
self.imageView.frame = CGRectMake(10, 10, 72, 72);
if ([self.managedObject valueForKey:@"imageLocation"] != nil) {
    NSLog(@"Trying to load the imageView with: %@", [self.managedObject valueForKey:@"imageLocation"]);
    UIImage *image = [[UIImage alloc] initWithContentsOfFile:[self.managedObject valueForKey:@"imageLocation"]];
    self.imageView.image = image;

} else {
    self.imageView.image = [UIImage imageNamed:@"no_picture_taken.png"];
}

我收到消息，它正在尝试在调试器中加载 imageView，但图像从未显示在 imageView 中。谁能告诉我我这里出了什么问题吗？

非常感谢。

您正在写出一个 NSData 对象，而不是图像。您需要读回 NSData 对象并转换为 UIImage。

假设其他一切都正确，请尝试以下操作：

NSData *data = [[NSData alloc] initWithContentsOfFile:[self.managedObject valueForKey:@"imageLocation"]];
UIImage *image = [[UIImage alloc] initWithData:data];