从桌面到iPhone的核心数据映像 [英] Core data images from desktop to iphone

问题描述

我建立了一个简单的Mac数据输入工具，我用于iPhone应用程序。我最近添加了我使用简单的绑定通过Image Well添加的缩略图。

I built a simple mac data entry tool I use with an iPhone application. I've recently added thumbnail which I added via an Image Well using simple bindings. Its a transformable data type which seems to work fine.

然而，iPhone应用程序不会显示图像。属性不是null，但我不能得到一个图像出现。以下是cellForRowAtIndexPath

The iPhone application however won't show the images. The attribute isn't null but I can't get an image to appear. The following is for cellForRowAtIndexPath

static NSString *CellIdentifier = @"Cell";

UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
    cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
}

NSManagedObject *entity = nil;
if ([self.searchDisplayController isActive])
    entity = [[self filteredListContent] objectAtIndex:[indexPath row]];
else
    entity = [fetchedResultsController objectAtIndexPath:indexPath];
cell.textLabel.text = [entity valueForKey:@"name"];
//cell.imageview.image = [UIImage imageNamed:@"ImageB.jpeg"]; //works fine
cell.imageView.image = [entity valueForKey:@"thumbnail"];//no error, but no file

return cell;

我想问题是与transformable（我使用默认NSKeyedUnarchiveFromData）或者我如何调用缩略图。我是一个新手，所以任何帮助将非常感激。

I'm thinking either the problem is with the transformable (I'm using the default NSKeyedUnarchiveFromData), or how I'm calling the thumbnail. I'm a newbie so any help would be greatly appreciated.

推荐答案

听起来像你存储的图像作为NSImage桌面，并且该对象在iPhone上不存在。您的桌面应用程序需要将图像存储在便携式设备，PNG或JPG等。然后，您可以将其作为UIImage加载到您的iPhone应用程序中。

Sounds like you are storing the image as an NSImage on the desktop and that object does not exist on the iPhone. Your desktop app needs to store the image in something that is portable, a PNG or JPG, etc. Then you will be able to load it back into your iPhone application as a UIImage.

听起来你还在传递一个NSImage到属性，它正在想你正在处理它的数据。您需要先将其转换为标准格式，如下所示：

Sounds like you are still passing in a NSImage to the attribute and it is thinking you are handling it data. You need to convert it to a "standard" format first, like this:

NSBitmapImageRep *bits = [[myImage representations] objectAtIndex: 0];

NSData *data = [bits representationUsingType:NSPNGFileType properties:nil];
[myManagedObject setImage:data];

我建议您编写自定义访问器来处理，例如：

I recommend writing custom accessors to handle this, like the following:

#ifdef IPHONEOS_DEPLOYMENT_TARGET

- (void)setImage:(UIImage*)image
{
  [self willChangeValueForKey:@"image"];

  NSData *data = UIImagePNGRepresentation(image);
  [myManagedObject setImage:data];
  [self setPrimitiveValue:data forKey:@"image"];
  [self didChangeValueForKey:@"image"];
}

- (UIImage*)image
{
  [self willAccessValueForKey:@"image"];
  UIImage *image = [UIImage imageWithData:[self primitiveValueForKey:@"image"];
  [self didAccessValueForKey:@"image"];
  return image;
}

#else

- (void)setImage:(NSImage*)image
{
  [self willChangeValueForKey:@"image"];
  NSBitmapImageRep *bits = [[image representations] objectAtIndex: 0];

  NSData *data = [bits representationUsingType:NSPNGFileType properties:nil];
  [myManagedObject setImage:data];
  [self setPrimitiveValue:data forKey:@"image"];
  [self didChangeValueForKey:@"image"];
}

- (NSImage*)image
{
  [self willAccessValueForKey:@"image"];
  NSImage *image = [[NSImage alloc] initWithData:[self primitiveValueForKey:@"image"]];
  [self didAccessValueForKey:@"image"];
  return [image autorelease];
}

#endif

编译并将数据存储为NSData（以PNG格式），可以在任何设备上检索。

This will give you a conditional compile and will store the data as NSData (in PNG format) that can be retrieved on any device.

这篇关于从桌面到iPhone的核心数据映像的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！