粘贴板上的多种类型，包括文件、rtfd 和自定义类型 (Mac OS X 10.6)
一旦您了解了 UTI，10.6 中的新粘贴板 api 似乎就可以很好地工作，但我遇到了一种无法破解的情况：如果您在文件拖动中声明多种数据类型怎么办？
查看新粘贴板的工作方式，您可以使用 setString、setData、setPropertyList 或 writeObjects 将数据放入其中。前 3 个要求您提前指定 UTI，以便接收者可以选择它想要的表示形式。
最后一个 - writeObjects - 需要一组符合 NSPasteboardWriting 的对象，例如便利类 NSPasteboardItem。
问题是 Finder 将添加到粘贴板的任何 url 解释为文字 url，因此它不是拖动文件，而是创建文件的 url。
没有办法（我可以找到）为 URL 创建 NSPasteboardItem。这就留下了这个（来自标题）：
APPKIT_EXTERN NSString *NSFilenamesPboardType; //Deprecated
// Use -writeObjects: to write file URLs to the pasteboard
但是，如果将 URL 与 NSPasteboard 项目混合，结果将不起作用。
NSPasteboardItem *noteItem = [[[NSPasteboardItem alloc] init] autorelease];
[noteItem setString:theString forType:NSPasteboardTypeString];
//Here is the problem: you can only have one or the other, not both.
[pasteboard writeObjects:[NSArray arrayWithObjects:noteItem, nil]]; //A
[pasteboard writeObjects:[NSArray arrayWithObject:fileURL]]; //B
// A or B will work but not both
[pasteboard writeObjects:[NSArray arrayWithObjects:
fileURL, noteItem, nil]]; //Will not work
如果有人可以写一些可以同时完成这两个任务的东西，我会认为这是一个很好的例子。
以下是测试：
拖动到 TextEdit 应插入文本
拖动到 Finder 应添加一个文件。
The new pasteboard api in 10.6 seems to work well once you get your head around UTIs, but I've come across a situation that I can't crack: What if you're declaring multiple data types in conjunction with a file drag?
See the way the new pasteboard works, you put data on it using setString, setData, setPropertyList, or writeObjects. The first 3 require that you specify the UTI in advance so the receiver can select the representation it wants.
The last one - writeObjects - requires an array of NSPasteboardWriting compliant objects, such as the convenience class NSPasteboardItem.
The problem is that the Finder interprets any url added to the pasteboard as a literal url, so rather than dragging a file it creates a url to the file.
There is no way (that I can find) to create an NSPasteboardItem for a URL. That leaves this (from the header):
APPKIT_EXTERN NSString *NSFilenamesPboardType; //Deprecated
// Use -writeObjects: to write file URLs to the pasteboard
However, if you mix a URL with an NSPasteboard item the result doesn't work.
NSPasteboardItem *noteItem = [[[NSPasteboardItem alloc] init] autorelease];
[noteItem setString:theString forType:NSPasteboardTypeString];
//Here is the problem: you can only have one or the other, not both.
[pasteboard writeObjects:[NSArray arrayWithObjects:noteItem, nil]]; //A
[pasteboard writeObjects:[NSArray arrayWithObject:fileURL]]; //B
// A or B will work but not both
[pasteboard writeObjects:[NSArray arrayWithObjects:
fileURL, noteItem, nil]]; //Will not work
I would consider it a great example if someone could write something that would accomplish both of these together.
Here is the test:
Drag to TextEdit should insert text
Drag to Finder should add a file.
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writeObjects: 不是唯一的方法。您还可以使用：
对于
NSURL您还有机会使用 NSURL 添加（+URLFromPasteboard:和-writeToPasteboard:）。writeObjects: is not the only method. You can also use:
For
NSURLyou also have the opportunity to use the NSURL Additions (+URLFromPasteboard:and-writeToPasteboard:).