dragging text produces 2 insertion points in NSTextView, and can not remove it

Question

This is the error picture:

My class is a subclass of NSTextView, it supports dragging. but When I drag text to former location, there will be a sticked inserting point.

Then I click elsewhere ,the normal insertion point appears at the end of text(which is correct),

but the first point did not disappear automatically, even though I delete the whole string.

there are only 3 method or property in NSTextView related to insertion point.

@property (readonly) BOOL shouldDrawInsertionPoint;
@property (copy) NSColor *insertionPointColor;

- (void)updateInsertionPointStateAndRestartTimer:(BOOL)restartFlag;
- (void)drawInsertionPointInRect:(NSRect)rect color:(NSColor *)color turnedOn:(BOOL)flag;

The first one is readonly, I tried the second one ,I set white color, when dragging and original color after dragActionEnded. I did not work.

Waiting for your resolution. Thanks!

The following is the drag delegate code I wrote. #pragma mark - Destination Operations

- (NSDragOperation)draggingEntered:(id <NSDraggingInfo>)sender

{ /------------------------------------------------------ method called whenever a drag enters our drop zone --------------------------------------------------------/

// Check if the pasteboard contains image data and source/user wants it copied
if ([sender draggingSourceOperationMask] & NSDragOperationCopy )
{
    //accept data as a copy operation
    return NSDragOperationCopy;
}

return NSDragOperationNone;

}

- (BOOL)prepareForDragOperation:(id <NSDraggingInfo>)sender

{

//check to see if we can accept the data
NSURL *fileURL=[NSURL URLFromPasteboard: [sender draggingPasteboard]];
if (fileURL == nil) {
return NO;}
NSString *filePathAndName = [[NSString alloc] initWithUTF8String:[fileURL fileSystemRepresentation]];
if (filePathAndName == nil)
{
    return NO;
}

NSString *fileExtension = [[filePathAndName pathExtension] uppercaseString];
if (fileExtension == nil)
{
    return NO;
}

if ([fileExtension isEqualToString:@"JPG"] ||
    [fileExtension isEqualToString:@"JPEG"] ||
    [fileExtension isEqualToString:@"PNG"] ||
    [fileExtension isEqualToString:@"GIF"] ||
    [fileExtension isEqualToString:@"BMP"])
{
    return YES;
}
else
{
    return NO;
}

}

- (BOOL)performDragOperation:(id <NSDraggingInfo>)sender{

if ( [sender draggingSource] != self )
{
    
if ( [[[sender draggingPasteboard] types] containsObject:NSFilenamesPboardType] ) {
NSURL* fileURL=[NSURL URLFromPasteboard: [sender draggingPasteboard]];
        NSArray *files = [[sender draggingPasteboard] propertyListForType:NSFilenamesPboardType];
        [[NSNotificationCenter defaultCenter] postNotificationName:ZayhuSendPicToPeer object:self userInfo:@{@"filesArray":files}];
    }
}

return YES;

}

- (NSString *)preferredPasteboardTypeFromArray:(NSArray *)availableTypes restrictedToTypesFromArray:(NSArray *)allowedTypes{
if ([availableTypes containsObject:NSPasteboardTypeString])
{
    return NSPasteboardTypeString;
}
return [super preferredPasteboardTypeFromArray:availableTypes restrictedToTypesFromArray:allowedTypes];

}

I tried your code. I get an exception and drag & drop of text doesn't work. Fix it and the inserting point will be ok. — Willeke
if (fileURL == nil) { return NO; } sorry,I did not check it ,Now, I add this line. It will work,but the problem is still there. — Tianyeye田野野

Banzon Banzon · Accepted Answer · 2016-11-07T03:32:13

I have encountered your problem.

My way to solve this problem is not subclassing NSTextView to do all drag and drop tasks but put NSTextView on a custom view and let the custom view do the main part of the job.

If i subclassed NSTextView to be the drag destination, i encountered some other UI problems such as disappearing insertion point when the textview is backed by a CALayer.

The following code are written in Swift, but it stills convey the idea for the solution.

First of all, for text drag & drop. You can subclass NSTextView and just override acceptableDragTypes

    override var acceptableDragTypes : [String] {
        return [NSStringPboardType]
    }

For other types of drag & drop, let the custom view deal with them. Take dragging files as example,

class MyCustomView: NSView {

    override init(frame frameRect: NSRect) {
        super.init(frame: frameRect)
        commonInit()
    }

    required init?(coder: NSCoder) {
        super.init(coder: coder)
        commonInit()
    }

    func commonInit() {
        registerForDraggedTypes([NSFilenamesPboardType])
    }

    override func draggingEntered(sender: NSDraggingInfo) -> NSDragOperation {
        if sender.draggingSource() === self {
            return .None
        }
        return sender.draggingSourceOperationMask()
    }

    override func prepareForDragOperation(sender: NSDraggingInfo) -> Bool {
        //add your custom logic here
        return true
    }

    override func performDragOperation(sender: NSDraggingInfo) -> Bool {
        //add your custom logic here
        return true
    }

 }

dragging text produces 2 insertion points in NSTextView, and can not remove it

2 Answers