如何检测NSTextView中图片的双击事件？

核心思路 #

给NSTextView添加双击手势识别，通过NSLayoutManager定位点击位置对应的文本附件，提取图片后调用预览应用打开。

具体实现步骤 #

• 自定义NSTextView子类，添加双击手势识别器
• 将点击坐标转换为文本容器内的坐标，通过NSLayoutManager获取对应字符索引
• 判断该字符是否为图片附件占位符，若是则提取NSTextAttachment和NSImage
• 将图片保存到临时目录，通过NSWorkspace调用预览打开临时文件

代码示例 #

class CustomTextView: NSTextView {
    override func awakeFromNib() {
        super.awakeFromNib()
        // 添加双击手势识别器
        let doubleClickGesture = NSClickGestureRecognizer(target: self, action: #selector(handleDoubleClick(_:)))
        doubleClickGesture.numberOfClicksRequired = 2
        addGestureRecognizer(doubleClickGesture)
    }
    
    @objc private func handleDoubleClick(_ gesture: NSClickGestureRecognizer) {
        let clickLocation = gesture.location(in: self)
        guard let textContainer = textContainer else { return }
        // 转换为文本容器内的坐标
        let containerLocation = convert(clickLocation, to: textContainer)
        
        guard let layoutManager = layoutManager else { return }
        // 获取点击位置对应的字符索引
        let characterIndex = layoutManager.characterIndex(for: containerLocation, in: textContainer, fractionOfDistanceBetweenInsertionPoints: nil)
        
        guard let textStorage = textStorage, characterIndex < textStorage.length else { return }
        // 判断是否是图片附件占位符
        if textStorage.string[textStorage.string.index(textStorage.string.startIndex, offsetBy: characterIndex)] == NSAttachmentCharacter {
            // 获取NSTextAttachment实例
            guard let attachment = textStorage.attribute(.attachment, at: characterIndex, effectiveRange: nil) as? NSTextAttachment,
                  let image = attachment.image else { return }
            
            // 保存图片到临时目录
            let tempDir = NSTemporaryDirectory()
            let tempFilePath = tempDir.appending("temp_preview_image.png")
            let tempFileURL = URL(fileURLWithPath: tempFilePath)
            
            do {
                // 将NSImage转为PNG数据
                guard let tiffData = image.tiffRepresentation,
                      let bitmapRep = NSBitmapImageRep(data: tiffData),
                      let pngData = bitmapRep.representation(using: .png, properties: [:]) else {
                    throw NSError(domain: "ImageConversionError", code: 0, userInfo: [NSLocalizedDescriptionKey: "无法转换图片格式"])
                }
                try pngData.write(to: tempFileURL)
                
                // 调用预览打开图片
                let previewAppURL = URL(fileURLWithPath: "/Applications/Preview.app")
                try NSWorkspace.shared.open([tempFileURL], withApplicationAt: previewAppURL, configuration: .init(), completionHandler: { success, error in
                    // 可选：打开后删除临时文件
                    if success {
                        try? FileManager.default.removeItem(at: tempFileURL)
                    }
                })
            } catch {
                print("处理图片失败: \(error.localizedDescription)")
            }
        }
    }
}

注意事项 #

• 若通过Storyboard/XIB创建NSTextView，需将其类改为CustomTextView
• 可根据原图片格式调整保存时的图片类型（如JPEG）
• 临时文件可在打开后自动删除，避免占用磁盘空间

内容的提问来源于stack exchange，提问作者Nilon123456789