NSTextView高亮显示选定的文本附件(图像和电影)，就像在苹果的笔记中一样

Question

我有一个NSTextView，可以拖放图片和mp4的。mov和pdf只能拖入，但不能拖出，因为它们不能被选中，只能回放。我喜欢和Apple的Notes App一样的功能。可以选择这些图像和视频(mov、mp4)并将其拖入和拖出。

我花了很多时间在互联网上寻找合适的解决方案，但找不到。

As I select a image, only the glyph is highlighted on the left side. Not the whole frame.

这是Apple的Notes App的截图，可以选择图片和电影，并将其拖入拖出。

Selected image and video in Apple's Notes App

下面是我的自定义textViewController类

//
//  RKTextViewController.h
//  RKon_OSX
//
//  Created by Robert Kyriakis on 23.10.20.
//  Copyright ©2020 RKon.eu. All rights reserved.
//

#import <Cocoa/Cocoa.h>

#import "RKTextView.h"

/*
 By double clicking a text attachment from the textView, the file is openend in Preview App.
 Making this work whitout errors the preview file must be copied to a location on the file system and exists there till the app terminates.
 Here it's copied to the app documents path within the directory /Documents/Previews/
 You must delete the 'Previews' directory either by lauching or terminating the app to clean it!
 */

@class RKTextViewController;

@protocol RKTextViewDelegate <NSObject>

@required
- (NSFont*)fontForTextView:(NSTextView*)textView;
- (NSColor*)textColorForTextView:(NSTextView*)textView;
- (NSColor*)placeholderTextColorForTextView:(NSTextView*)textView;
- (NSString*)placeholderStringForTextView:(NSTextView*)textView;

@optional
- (void)textDidBeginEditing:(NSTextView*)textView;
- (void)textDidEndEditing:(NSTextView*)textView;

@end

@interface RKTextViewController : NSViewController

@property (nonatomic, strong) IBOutlet RKTextView *textView;
@property (nonatomic, strong) IBOutlet NSProgressIndicator *progressIndicator;

@property BOOL contentHasChanged;
@property id <RKTextViewDelegate> rkTextViewDelegate;

- (void)updateTextViewWithTextStorage:(NSTextStorage*)textStorage;

@end

//
//  RKTextViewController.m
//  RKon_OSX
//
//  Created by Robert Kyriakis on 23.10.20.
//  Copyright ©2020 RKon.eu. All rights reserved.
//

#import <RKon_OSX/RKon_OSX.h>

#import "RKTextViewController.h"

@interface RKTextViewController () <NSTextViewDelegate>

@property (nonatomic, strong) NSFont *textViewFont;
@property (nonatomic, strong) NSColor *textColor;
@property (nonatomic, strong) NSColor *placeholderTextColor;
@property (nonatomic, strong) NSString *placeholderString;

@end

@implementation RKTextViewController

- (void)awakeFromNib
{
    [self initProperties];
}

#pragma mark - Extensions
- (void)initProperties
{
    dispatch_async(dispatch_get_main_queue(), ^{
        
        self.textView.delegate = self;
        
        // this property must be set to determine, when dragging into the textView
        // makes changes and the boolean contentHasChanged here can be set
        self.textView.rkTextViewController = self;
        
        if (self.rkTextViewDelegate && [self.rkTextViewDelegate respondsToSelector:@selector(fontForTextView:)]) {
            self.textViewFont = [self.rkTextViewDelegate fontForTextView:self.textView];
            self.textView.font = self->_textViewFont;
        }
        
        if (self.rkTextViewDelegate && [self.rkTextViewDelegate respondsToSelector:@selector(textColorForTextView:)]) {
            self.textColor = [self.rkTextViewDelegate textColorForTextView:self.textView];
        }
        
        if (self.rkTextViewDelegate && [self.rkTextViewDelegate respondsToSelector:@selector(placeholderTextColorForTextView:)]) {
            self.placeholderTextColor = [self.rkTextViewDelegate placeholderTextColorForTextView:self.textView];
            self.textView.textColor = self->_placeholderTextColor;
        }
        
        if (self.rkTextViewDelegate && [self.rkTextViewDelegate respondsToSelector:@selector(placeholderStringForTextView:)]) {
            self.placeholderString = [self.rkTextViewDelegate placeholderStringForTextView:self.textView];
            self.textView.string = self->_placeholderString;
        }
        
        self.textView.allowsUndo = YES;
        self.textView.selectable = YES;
        
        self.textView.richText = YES;
        self.textView.importsGraphics = YES;
        self.textView.allowsImageEditing = YES;
        
        self.textView.automaticLinkDetectionEnabled = YES;
        self.textView.automaticDataDetectionEnabled = YES;
        
        self.textView.smartInsertDeleteEnabled = YES;
        
        // automitically scale larger images or other content to fit in the textView
        self.textView.layoutManager.defaultAttachmentScaling = NSImageScaleProportionallyDown;
        self.textView.layoutManager.allowsNonContiguousLayout = YES;
        
        self.contentHasChanged = NO;
        
        [RKLogger logDebugInfoFromObject:self withSelector:_cmd log:@"contentHasChanged = NO"];
        
        // register video pboard types
        // videos are not allowed jet. They can be dropped, but not dragged out of the textView
//        NSString *movPboardType = NSCreateFileContentsPboardType(@"mov");
//        NSString *mp4PboardType = NSCreateFileContentsPboardType(@"mp4");
        
//        [self.textView registerForDraggedTypes:@[NSFilenamesPboardType,movPboardType,mp4PboardType]];
    });

}

- (void)updateTextViewWithTextStorage:(NSTextStorage*)textStorage
{
    [_progressIndicator startAnimation:self];
    
    dispatch_async(dispatch_get_main_queue(), ^{
        
        NSTextStorage *newTextStorage;
        NSData *textStorageData;
        NSAttributedString *attributedString;
        
        if (textStorage) {
            // check the data of the textStorage,
            // because the storage can have only glyphs with attachments
            textStorageData = [NSKeyedArchiver archivedDataWithRootObject:textStorage];
            attributedString = [NSKeyedUnarchiver unarchiveObjectWithData:textStorageData];
            
            // first manage the textStorage, with default font and text color
            if (attributedString && (attributedString.length > 0)) {
                newTextStorage = [[NSTextStorage alloc] initWithAttributedString:attributedString];
            } else {
                newTextStorage = [[NSTextStorage alloc] initWithString:self->_placeholderString];
            }
        } else {
            // textStorage is Nil
            // return only placeholder string
            newTextStorage = [[NSTextStorage alloc] initWithString:self->_placeholderString];
        }
        
        [self.textView.layoutManager replaceTextStorage:newTextStorage];

        // Important textColor and font must be set after
        // the textStorage is replaced in the noteTextView to have an effect

        self.textView.font = self->_textViewFont;
        
        if (attributedString && (attributedString.length > 0)) {
            self.textView.textColor = self->_textColor;
        } else {
            self.textView.textColor = self->_placeholderTextColor;
        }
        
        // TextView must be redrawn in the case of large attributes
        // to take effect with delay on main runloop
        [self performSelector:@selector(refreshTextView) withObject:Nil afterDelay:0.02];
    });
}

- (void)refreshTextView
{
    dispatch_async(dispatch_get_main_queue(), ^{
        
        NSRect rect = self.textView.bounds;
        
        [self.textView setNeedsDisplayInRect:rect
                       avoidAdditionalLayout:YES];
        
        [self.progressIndicator stopAnimation:self];

    });

}

#pragma mark - NSTextViewDelegate methods
- (BOOL)textShouldBeginEditing:(NSText*)textObject
{
    dispatch_async(dispatch_get_main_queue(), ^{
        
        // while editing the note text set always the text color
        // some times it chanes after drop of images
        textObject.textColor = self->_textColor;
        textObject.font = self->_textViewFont;
        
    });

    return YES;

}

- (void)textDidBeginEditing:(NSNotification *)notification
{
    dispatch_async(dispatch_get_main_queue(), ^{
        
        NSTextView *textView = (NSTextView*)notification.object;
        
        // while editing the note text set always the text color
        // some times it chanes after drop of images
        textView.textColor = self->_textColor;
        textView.font = self->_textViewFont;
        
        if (self.rkTextViewDelegate && [self.rkTextViewDelegate respondsToSelector:@selector(textDidBeginEditing:)]) {
            [self.rkTextViewDelegate textDidBeginEditing:textView];
        }
        
// removing placeholderstring when typing the first
// character doesn't work, when an object is dropped into the textView first
/*
        // remove placeholder string, when it's at the begining
        NSString *string = textView.textStorage.string;
        
        NSRange placeholderStringRange = [string rangeOfString:self->_placeholderString options:NSCaseInsensitiveSearch];
        
        if ((placeholderStringRange.location == 0) && (placeholderStringRange.length == self->_placeholderString.length)) {
            textView.string = [textView.string stringByReplacingOccurrencesOfString:self->_placeholderString withString:@""];
        }
*/
    });
    
}

- (void)textDidEndEditing:(NSNotification *)notification
{
    NSTextView *textView = (NSTextView*)notification.object;

    if (self.rkTextViewDelegate && [self.rkTextViewDelegate respondsToSelector:@selector(textDidBeginEditing:)]) {
        [self.rkTextViewDelegate textDidEndEditing:textView];
    }
    
    _contentHasChanged = YES;
    
    [RKLogger logDebugInfoFromObject:self withSelector:_cmd log:@"contentHasChanged = YES"];

}

#pragma mark - drag & drop
- (void)textView:(NSTextView*)view
     draggedCell:(id<NSTextAttachmentCell>)cell
          inRect:(NSRect)rect
           event:(NSEvent*)event
         atIndex:(NSUInteger)charIndex;
{
    [RKLogger logDebugInfoFromObject:Nil withSelector:_cmd log:Nil];

    NSTextAttachment *textAttachment = cell.attachment;
//    NSString *fileType = textAttachment.fileType;
    NSFileWrapper *fileWrapper = textAttachment.fileWrapper;

    NSURL *documentsURL = [RKFileManager userApplicationDocumentsURL];
    NSURL *fileURL = [documentsURL URLByAppendingPathComponent:fileWrapper.preferredFilename];
    
    // because the method after need a file at path
    // first write the fileWrapper to an URL
    NSError *error;
    [fileWrapper writeToURL:fileURL
                    options:NSFileWrapperWritingAtomic
        originalContentsURL:Nil
                      error:&error];
    
    if (!error) {
        [view dragFile:fileURL.path
              fromRect:rect
             slideBack:YES
                 event:event];

        // now the file at app docuemnts path is no longer neccesary
        // and can be deleted
        [[NSFileManager defaultManager] removeItemAtPath:fileURL.path
                                                   error:&error];
    }
    
    if (error) {
        [RKError showRKAlertWithError:error completion:^{
        }];
    }
    
//     This is not working, only the attributed string with pblic.rtf pboard is dragged
//     NSTextAttachment *textAttachment = cell.attachment;
//     NSAttributedString *attributedString = [NSAttributedString attributedStringWithAttachment:textAttachment];
     
//     NSDraggingItem *draggingItem = [[NSDraggingItem alloc] initWithPasteboardWriter:attributedString];
//     draggingItem.draggingFrame = rect;
     
//     [self.textView beginDraggingSessionWithItems:@[draggingItem]
//     event:event
//     source:self.textView];
    
    
}


@end

下面是我的自定义textView类

//
//  RKTextView.h
//  RKon_OSX
//
//  Created by Robert Kyriakis on 26.10.20.
//  Copyright ©2020 RKon.eu. All rights reserved.
//

#import <Cocoa/Cocoa.h>

#import "RKTextViewController.h"

@class RKTextViewController;

/*
 By double clicking a text attachment from the textView, the file is openend in Preview App.
 Making this work whitout errors the preview file must be copied to a location on the file system and exists there till the app terminates.
 Here it's copied to the app documents path within the directory /Documents/Previews/
 You must delete the 'Previews' directory either by lauching or terminating the app to clean it!
 */

@interface RKTextView : NSTextView

@property (nonatomic, strong) RKTextViewController *rkTextViewController;

@end

//
//  RKTextView.m
//  RKon_OSX
//
//  Created by Robert Kyriakis on 26.10.20.
//  Copyright ©2020 RKon.eu. All rights reserved.
//

#import <RKon_OSX/RKon_OSX.h>

#import "RKTextView.h"

@interface RKTextView ()

//@property NSPoint dropPoint;

@end

@implementation RKTextView

- (void)drawRect:(NSRect)dirtyRect {
    [super drawRect:dirtyRect];
    
    // Drawing code here.
}

- (void)mouseDown:(NSEvent*)event
{
    if (event.clickCount == 2) {
        // doubleClikk detected
        // get fileWrapper of the attributedString at mouse point
        NSPoint doubleClickPoint = [self convertPoint:[event locationInWindow]
                                             fromView:nil];
        
        NSUInteger attribIndex = [self characterIndexForInsertionAtPoint:doubleClickPoint];
        
        // get the attributes at index
        NSDictionary <NSAttributedStringKey, id> *attributesDict = [self.textStorage attributesAtIndex:attribIndex effectiveRange:Nil];
        
        // set the attachment, if exists
        NSTextAttachment *attachment = [attributesDict valueForKey:NSAttachmentAttributeName];
        
        // check, if an attachment exists
        if (attachment) {
            // there is an attachment with a fileWrapper
            NSFileWrapper *fileWrapper = attachment.fileWrapper;
            
            // bevor oppening the file in an app it has to be stored at a path.
            // It can't be deleted from this path, while an application like Preview want's to save it later!!
            // You must delete all files from that folder when lounging the app.
            NSURL *documentsURL = [RKFileManager userApplicationDocumentsURL];
            NSURL *docPreviewsURL = [documentsURL URLByAppendingPathComponent:@"Previews"];
            
            // check, if previews path exists
            NSFileManager *fileManager = [NSFileManager defaultManager];
            NSError *error;
            BOOL isDirectory;
            
            if (![fileManager fileExistsAtPath:docPreviewsURL.path isDirectory:&isDirectory]) {
                // not exists -> create it
                [fileManager createDirectoryAtPath:docPreviewsURL.path
                       withIntermediateDirectories:NO
                                        attributes:Nil
                                             error:&error];
                
                if (error) {
                    [RKError showRKAlertWithError:error completion:^{
                    }];
                    return;
                }
            }
            
            NSURL *fileURL = [docPreviewsURL URLByAppendingPathComponent:fileWrapper.preferredFilename];
            
            // because the method after need a file at path
            // first write the fileWrapper to an URL
            [fileWrapper writeToURL:fileURL
                            options:NSFileWrapperWritingAtomic
                originalContentsURL:Nil
                              error:&error];
            
            if (!error) {
                
                // open attachment with preview app
                NSString *previewAppPath = [[NSWorkspace sharedWorkspace] fullPathForApplication:@"Preview"];
                [[NSWorkspace sharedWorkspace] openFile:fileURL.path withApplication:previewAppPath];
            }
            
            if (error) {
                [RKError showRKAlertWithError:error completion:^{
                }];
            }

        } else {
            // no attachement exists, so it's only a text without attachments
            // call only super
            [super mouseDown:event];
        }
        
    } else {
        // by ontime mouse click call only super
        [super mouseDown:event];
    }
     
  
    NSPoint dragPosition = [self convertPoint:event.locationInWindow
                                     fromView:Nil];

    [RKLogger logDebugInfoFromObject:Nil withSelector:_cmd log:[NSString stringWithFormat:@"Dragposition (x/y) (%.0f/%.0f)",dragPosition.x,dragPosition.y]];
    
}

#pragma mark - Drag & Drop methods
- (BOOL)performDragOperation:(id<NSDraggingInfo>)sender
{
    [RKLogger logDebugInfoFromObject:Nil withSelector:_cmd log:Nil];

//    return [super performDragOperation:sender];

    BOOL performDragginOperation = NO;
    
    NSPasteboard *pboard = [sender draggingPasteboard];
    NSArray *pboardTypes = [pboard types];
    NSDragOperation dragOperation = NSDragOperationNone;
    
    NSTextAttachment *attachment;
    NSAttributedString *attributedString;
    
    // dragging files into the TextView
    if ([pboardTypes containsObject:NSFilenamesPboardType]) {
        
        NSArray *files = [pboard propertyListForType:NSFilenamesPboardType];
        
        for (NSString *filePath in files) {

            NSString *fileName = filePath.lastPathComponent;
            // turn all filename signs to lowercase to compare suffixes
            NSString *lowercaseFileName = [fileName lowercaseString];;
            
            if (
                [lowercaseFileName hasSuffix:@"jpg"] || [lowercaseFileName hasSuffix:@"jpeg"] ||
                [lowercaseFileName hasSuffix:@"png"] ||
                [lowercaseFileName hasSuffix:@"gif"] ||
                [lowercaseFileName hasSuffix:@"tif"] || [lowercaseFileName hasSuffix:@"tiff"] ||
                [lowercaseFileName hasSuffix:@"psd"] ||
                [lowercaseFileName hasSuffix:@"pdf"] ||
                [lowercaseFileName hasSuffix:@"icns"]
                ) {
                dragOperation = NSDragOperationEvery;
            }
            
            if (dragOperation == NSDragOperationEvery) {
                // dragged file is valid for dragging

                NSError *error;
                NSURL *url = [NSURL fileURLWithPath:filePath];
                NSFileWrapper *fileWrapper = [[NSFileWrapper alloc] initWithURL:url
                                                                        options:NSFileWrapperReadingImmediate
                                                                          error:&error];
                if (!error) {
                    fileWrapper.preferredFilename = filePath.lastPathComponent;
                    
                    // insert the dragged file at cursor position
                    attachment = [[NSTextAttachment alloc] initWithFileWrapper:fileWrapper];
                    attributedString = [NSAttributedString attributedStringWithAttachment:attachment];
                    
                    NSPoint dropPoint = [self convertPoint:[sender draggingLocation] fromView:Nil];
                    NSUInteger caretLocation = [self characterIndexForInsertionAtPoint:dropPoint];
                    // insert the new attachment at dragging cursor position
                    [self.textStorage insertAttributedString:attributedString atIndex:caretLocation];

                    // check, if the attributedString already exists and remove it
                    [self.textStorage enumerateAttribute:NSAttachmentAttributeName
                                                 inRange:NSMakeRange(0, self.textStorage.length)
                                                 options:0
                                              usingBlock:^(id  _Nullable value, NSRange range, BOOL * _Nonnull stop) {
                        NSTextAttachment *attachement = (NSTextAttachment*)value;
                        
                        if ([attachement.fileWrapper.preferredFilename isEqualToString:filePath.lastPathComponent]) {
                            // same attachment found
                            // check, if it's the new inserted
                            if (range.location != caretLocation) {
                                // is not, so delete it
//                                [self.textStorage replaceCharactersInRange:range withString:@""];
                                [self.textStorage deleteCharactersInRange:range];
                                *stop = YES;
                            }
                        }
                        
                    }];
                    
                    _rkTextViewController.contentHasChanged = YES;

                } else {
                    [RKError showRKAlertWithError:error completion:Nil];
                    dragOperation = NSDragOperationNone;
                }
            }
        }
    }

    if (dragOperation == NSDragOperationEvery) {
        performDragginOperation = YES;
    } else {
        performDragginOperation = NO;
    }
    
    return performDragginOperation;

}

Answer 1

如果你想要能够将媒体从拖拽到你的应用中，那么你需要将你的窗口设置为拖动源和拖拽目的地。

这里有一个关于这个东西的很好的入门教程：https://www.raywenderlich.com/1016-drag-and-drop-tutorial-for-macos

如果你已经看过这篇文章，很抱歉。