Drag and Drop folder view cocoa

I need to make a drag and drop view in cocoa that will accept folders. I know it will use things like NSView and probably registerForDraggedTypes: (which I still am not sure how to go about using). Does a开发者_StackOverflow中文版nyone know how to get this working?

Thanks in advance

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1. Make a class called DragDropView that subclasses NSView and set the view in MainMenu.xib to be of this type (Select your view, go to Identity Inspecor and write DragDropView in Custom Class).

2. Write the code (see below) for DragDropView and Run it. An empty window should appear.

3. Drag some folders onto your window. You should get the paths of the folders written in your console. Something like.

2014-02-01 11:18:10.435 Start[41767:303] ( "/Users/bob/Desktop/Heathers Animations", "/Users/bob/Desktop/bird.atlas" )

// DragDropView.h
#import <Cocoa/Cocoa.h>

@interface DragDropView : NSView

@end

// DragDropView.m
#import "DragDropView.h"

@implementation DragDropView {
    BOOL isHighlighted;
}

- (void)awakeFromNib {
    [self registerForDraggedTypes:[NSArray arrayWithObjects:NSFilenamesPboardType, nil]];
}

- (BOOL)isHighlighted {
    return isHighlighted;
}

- (void)setHighlighted:(BOOL)value {
    isHighlighted = value;
    [self setNeedsDisplay:YES];
}

- (void)drawRect:(NSRect)frame {
    [super drawRect:frame];
    if (isHighlighted) {
        [NSBezierPath setDefaultLineWidth:6.0];
        [[NSColor keyboardFocusIndicatorColor] set];
        [NSBezierPath strokeRect:frame];
    }
}


#pragma mark - Dragging

- (NSDragOperation)draggingEntered:(id <NSDraggingInfo>)sender {
    NSPasteboard *pboard = [sender draggingPasteboard];

    if ([[pboard types] containsObject:NSFilenamesPboardType]) {
        NSArray *paths = [pboard propertyListForType:NSFilenamesPboardType];
        for (NSString *path in paths) {
            NSError *error = nil;
            NSString *utiType = [[NSWorkspace sharedWorkspace]
                                 typeOfFile:path error:&error];
            if (![[NSWorkspace sharedWorkspace]
                  type:utiType conformsToType:(id)kUTTypeFolder]) {

                [self setHighlighted:NO];
                return NSDragOperationNone;
            }
        }
    }
    [self setHighlighted:YES];
    return NSDragOperationEvery;
}

- (void)draggingExited:(id <NSDraggingInfo>)sender {
    [self setHighlighted:NO];
}


- (BOOL)prepareForDragOperation:(id <NSDraggingInfo>)sender  {
    return YES;
}

- (BOOL)performDragOperation:(id <NSDraggingInfo>)sender {
    [self setHighlighted:NO];
    return YES;
}

- (void)concludeDragOperation:(id<NSDraggingInfo>)sender {
    NSArray *files = [[sender draggingPasteboard] propertyListForType:NSFilenamesPboardType];
    NSLog(@"%@", files);
}

@end

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Most of what you need is in the drag and drop documentation, but what you need specifically is the NSFilenamesPboardType. It's an array if file paths.