问题描述
我可能犯了一个简单的错误，但是我根本无法将文件拖放到NSCollectionView上，即使以最基本的方式工作也是如此.
There is probably a simple mistake that I'm making, but I simply cannot get dropping of files onto an NSCollectionView to work even in the most basic way.
在一个测试项目中，我在窗口上有一个NSCollectionView，而视图控制器既是其委托者，又是数据源.我希望能够将文件从Finder拖到该集合视图中.
In a test project, I have an NSCollectionView on a window, and the view controller is both its delegate and data source. I want to be able to drag files from the Finder onto this collection view.
通过阅读文档，我要做的就是:
From reading the docs, all I should have to do is:
注册拖动类型:
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view.
NSLog(@"Registering dragged types for collection view: %@", self.collectionView);
[self.collectionView registerForDraggedTypes:@[NSFilenamesPboardType]];
[self.collectionView setDraggingSourceOperationMask:NSDragOperationEvery forLocal:YES];
[self.collectionView setDraggingSourceOperationMask:NSDragOperationEvery forLocal:NO];
}
然后实现这两种方法:
-(NSDragOperation)collectionView:(NSCollectionView *)collectionView validateDrop:(id<NSDraggingInfo>)draggingInfo proposedIndex:(NSInteger *)proposedDropIndex dropOperation:(NSCollectionViewDropOperation *)proposedDropOperation {
NSLog(@"Validate drop: %@", draggingInfo);
return NSDragOperationMove;
}
-(BOOL)collectionView:(NSCollectionView *)collectionView acceptDrop:(id<NSDraggingInfo>)draggingInfo index:(NSInteger)index dropOperation:(NSCollectionViewDropOperation)dropOperation {
NSLog(@"Accept drop: %@", draggingInfo);
return YES;
}
但是，当我尝试将一个项目拖到集合视图上时，这两个方法都没有被调用过，这使我认为 registerForDraggedTypes:调用未按预期工作.
But none of the two methods is ever called, when I try to drag an item onto the collection view, which makes me think that the registerForDraggedTypes: call is not working as expected.
这里可能是什么问题?我还需要研究什么?
What can be the issue here? What else do I have to look into?
推荐答案
从OS X 10.11起， NSCollectionViewDelegate 方法采用索引路径而不是索引路径.例如
From OS X 10.11 the NSCollectionViewDelegate methods take an index path instead of an index. For instance in
-(NSDragOperation)collectionView:(NSCollectionView *)collectionView validateDrop:(id<NSDraggingInfo>)draggingInfo proposedIndex:(NSInteger *)proposedDropIndex dropOperation:(NSCollectionViewDropOperation *)proposedDropOperation
proposedIndex:参数替换为 proposedIndexPath:
- (NSDragOperation)collectionView:(NSCollectionView *)collectionView validateDrop:(id <NSDraggingInfo>)draggingInfo proposedIndexPath:(NSIndexPath * __nonnull * __nonnull)proposedDropIndexPath dropOperation:(NSCollectionViewDropOperation *)proposedDropOperation
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