macos - 如何在NSViewController中调用registerForDraggedTypes？

Question

我有一个 MainViewController ，其中有一个 splitview 。接下来，我有两个 View Controller 来控制分割 View 中的每个 View 。我希望能够在这些 View 之一中拖放文件。

但我似乎无法让拖动工作？当将文件拖到 View 中时，文件上没有“加号”，并且放下它也不会执行任何操作。

我做错了什么？

首先是 MainViewController.m

fileViewController = [[FileViewController alloc] initWithNibName:@"FileViewController" bundle:nil];
terminalViewController = [[TerminalViewController alloc] initWithNibName:@"TerminalViewController" bundle:nil];

[splitView replaceSubview:[[splitView subviews] objectAtIndex:0] with:[fileViewController view]];
[splitView replaceSubview:[[splitView subviews] objectAtIndex:1] with:[terminalViewController view]];

接下来，我的代码用于处理 FileViewController 中的拖动

@dynamic isHighlighted;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        NSLog(@"registering");
        [self.view registerForDraggedTypes:[NSArray arrayWithObjects: NSFilenamesPboardType, nil]];
    }



    return self;
}

- (NSDragOperation)draggingEntered:(id <NSDraggingInfo>)sender {
    NSLog(@"[%@ %@]", NSStringFromClass([self class]), NSStringFromSelector(_cmd));

    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 )sender {
    [self.view setNeedsDisplay:YES];
} // end concludeDragOperation

- (BOOL)isHighlighted {
    return isHighlighted;
}

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

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

Answer 1

我似乎没有修复它，因为没有人给我任何答案，我通过创建一个 NSView 子类并将其添加到我的 View Controller 中来修复它，如下所示。

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        draggable = [[DragView alloc] initWithFrame:CGRectMake(0, 0, 500, 500)];
        [[self view] addSubview:draggable];
    }

    return self;
}