我正在向 NSPasteboard 写入一些对象以进行拖动操作beginDraggingSessionWithItems:event:source:
:
NSMutableArray *draggingItems = [NSMutableArray array];
for (NSUInteger i = 0; i < numItems; i++) {
NSPasteboardItem *pasteboardItem = [NSPasteboardItem new];
[pasteboardItem setDataProvider:[MyItem itemForIndex:i]
forTypes:@[@"com.test.FooType"]];
NSDraggingItem *draggingItem = [[NSDraggingItem alloc] initWithPasteboardWriter:pasteboardItem];
// ...
[draggingItems addObject:draggingItem];
}
[sourceView beginDraggingSessionWithItems:draggingItems
event:theEvent
source:self];
在拖动目的地(在同一个应用程序中),我尝试使用 接收这些项目readObjectsForClasses:options:
,但我只收到其中一个。
- (BOOL)performDragOperation:(id<NSDraggingInfo>)sender
{
// sender.draggingPasteboard.pasteboardItems contains all items
NSArray *myItems = [sender.draggingPasteboard readObjectsForClasses:@[[MyItem class]] options:nil];
// pasteboard:item:provideDataForType: is called for each object on the pasteboard...
// ...but this method only returns 1 object (the first one)??
(请注意,如果您通过@[[NSPasteboardItem class]]
了课程,您将获得所有未修改的项目。)
知道为什么会发生这种情况吗?此处提供示例项目(包含大量 NSLogs 以查看项目实际上正在写入粘贴板)。