NSTextView 中的 Xcode 风格占位符

Question

在 Xcode 中，如果输入 <# Hello, Word #>在文本编辑器中，它会自动转换为淡蓝色药丸状占位符，但在磁盘上，文本仍与键入时完全相同。有谁知道使用 NSTextView 是否可以实现相同的效果？我有一些非常难看的文件路径，它们必须保持原样sphinx可以将我的文档放在一起，但我想在用户在我的自定义文本编辑器中查看文件时向他们展示更具吸引力的内容。

// This on disk (and in any other text editor)
.. image:: images/ssafs/sdfd-sdfsdg-ewfsdf.png

// This shown to the user in my custom text editor
Image of a golden eagle

Answer 1

尽可能尝试将解释写为代码中的注释。我在这里做了什么。

1. 使用正则表达式找到所有匹配的链接.. image::images/ssafs/sdfd-sdfsdg-ewfsdf1.png并将它们添加到数组中。
2. 将所有匹配的链接 .. image::images/ssafs/sdfd-sdfsdg-ewfsdf1.png 替换为 [Image] 字符串
3. 找到所有 [Image] 字符串并使用 NSMutableAttributedString 作为链接进行格式化。

它会执行您所要求的操作，并且会即时执行，数据库/文件中的源代码根本不会更改。

.h

#import <Cocoa/Cocoa.h>

@interface AppDelegate : NSObject <NSApplicationDelegate, NSTextViewDelegate>
@property (unsafe_unretained) IBOutlet NSTextView *aTextView;

.m

- (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
    
    //Your NSTextView
    [aTextView setDelegate:(id)self];
    
    // The Context
    NSString *string = @"Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec convallis .. image:: images/ssafs/sdfd-sdfsdg-ewfsdf1.png lacinia diam, in mattis quam egestas in. Nam gravida dolor adipiscing velit faucibus, vulputate facilisis diam facilisis. Duis id magna nibh. Proin sed turpis aliquet .. image:: images/ssafs/sdfd-sdfsdg-ewfsdf2.png, posuere purus eget, condimentum nulla. Aenean erat odio, suscipit eu aliquet eget, porta in justo. Quisque sed sem dignissim, luctus .. image:: images/ssafs/sdfd-sdfsdg-ewfsdf3.png libero ut, congue libero. Curabitur tristique fermentum risus in fermentum.";
    
    //Regex to find your links .. image:: images/ssafs/sdfd-sdfsdg-ewfsdf2.png
    //You can / should improve Reges patter.
    NSRegularExpression *regexPatternForFullLinks = [NSRegularExpression regularExpressionWithPattern:@"(\\.\\.\\s(.*?\\.png))"
                                                                                              options:NSRegularExpressionCaseInsensitive error:nil];
    //Here find all image links and add them into an Array
    NSArray *arrayOfAllMatches = [regexPatternForFullLinks matchesInString:string options:0 range:NSMakeRange(0, string.length)];
    NSMutableArray *links = [[NSMutableArray alloc] init];
    for (NSTextCheckingResult *match in arrayOfAllMatches) {
        [links addObject:[[string substringWithRange:match.range] stringByReplacingOccurrencesOfString:@".. image:: " withString:@"/"]];
    }

    //Replacing All your links with string: [Image]
    NSString *modifiedString = [regexPatternForFullLinks stringByReplacingMatchesInString:string
                                                                                  options:0
                                                                                    range:NSMakeRange(0, [string length])
                                                                             withTemplate:@"[Image]"];
    
    NSRegularExpression *regexPatternReplaceLinksWithIMAGEStr = [NSRegularExpression regularExpressionWithPattern:@"\\[image\\]"
                                                                                              options:NSRegularExpressionCaseInsensitive error:nil];
    
    NSMutableAttributedString* attrString = [[NSMutableAttributedString alloc] initWithString:modifiedString];
    
    //Here,looking for all [Image] strings and add them Link Attribute
    NSArray *arrayOfAllMatchesImageText = [regexPatternReplaceLinksWithIMAGEStr matchesInString:modifiedString
                                                                                        options:0
                                                                                          range:NSMakeRange(0, modifiedString.length)];
   
    for (int i = 0; i < arrayOfAllMatchesImageText.count; i++) {
        NSTextCheckingResult *checkingResult = [arrayOfAllMatchesImageText objectAtIndex:i];
        [attrString beginEditing];
        [attrString addAttribute:NSLinkAttributeName value:[links objectAtIndex:i] range:checkingResult.range];
        [attrString addAttribute:NSForegroundColorAttributeName value:[NSColor greenColor] range:checkingResult.range];
        [attrString addAttribute:NSUnderlineStyleAttributeName value:[NSNumber numberWithInt:0] range:checkingResult.range];
        [attrString endEditing];
    }
    
    //Set NSTextView Storage text...
    [aTextView.textStorage setAttributedString:attrString];
}

NSTextViewDelegate:clickedOnLink 处理链接点击。

//Open Given Links with Preview App - NSTextViewDelegate 
- (BOOL)textView:(NSTextView *)aTextView clickedOnLink:(id)link atIndex:(NSUInteger)charIndex {
    [[NSWorkspace sharedWorkspace] openFile:link withApplication:@"Preview"];
    NSLog(@"%@", link);
    return YES;
}

您可以在图像上看到最终结果。如果您愿意，您也可以为链接提供背景颜色。

NSTextView 设置也很重要。

更新:

只要弄清楚这可以更优雅地完成，而且效率更高(更快)。

- (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
    //Your NSTextView
    [aTextView setDelegate:(id)self];
    
    // The Context
    NSString *string = @"Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec convallis .. image:: images/ssafs/sdfd-sdfsdg-ewfsdf1.png lacinia diam, in mattis quam egestas in. Nam gravida dolor adipiscing velit faucibus, vulputate facilisis diam facilisis. Duis id magna nibh. Proin sed turpis aliquet .. image:: images/ssafs/sdfd-sdfsdg-ewfsdf2.png, posuere purus eget, condimentum nulla. Aenean erat odio, suscipit eu aliquet eget, porta in justo. Quisque sed sem dignissim, luctus .. image:: images/ssafs/sdfd-sdfsdg-ewfsdf3.png libero ut, congue libero. Curabitur tristique fermentum risus in fermentum.";
    
    //Regex to find your links .. image:: images/ssafs/sdfd-sdfsdg-ewfsdf2.png
    //You can / should improve Reges patter.
    NSRegularExpression *regexPatternForFullLinks = [NSRegularExpression regularExpressionWithPattern:@"(\\.\\.\\s(.*?\\.png))"
                                                                                              options:NSRegularExpressionCaseInsensitive error:nil];
    //Here find all image links and add them into an Array
    NSArray *arrayOfAllMatches = [regexPatternForFullLinks matchesInString:string options:0 range:NSMakeRange(0, string.length)];
    
    __block NSMutableAttributedString* attrString = [[NSMutableAttributedString alloc] initWithString:string];

    [arrayOfAllMatches enumerateObjectsWithOptions:NSEnumerationReverse usingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
        NSTextCheckingResult *match = [arrayOfAllMatches objectAtIndex:idx];
        NSString *linkValue = [[string substringWithRange:match.range] stringByReplacingOccurrencesOfString:@".. image:: " withString:@"/"];
        NSDictionary *linkAttributes = @{NSForegroundColorAttributeName: [NSColor greenColor],
                                         NSUnderlineStyleAttributeName: [NSNumber numberWithInt:0],
                                         NSLinkAttributeName:linkValue};
        
        NSMutableAttributedString *tempAttrString = [[NSMutableAttributedString alloc] initWithString:@"[Image]" attributes:linkAttributes];
        [attrString beginEditing];
        [attrString replaceCharactersInRange:match.range withAttributedString:tempAttrString];
        [attrString endEditing];
    }];
    [aTextView.textStorage setAttributedString:attrString];
}