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我希望 NSTextView 对象通过更改 NSParagraphStyle 间距来对击中的 Tab 键做出反应。它确实如此，但非常慢！！！事实上，如果我这样做太快（按 Tab 键太快），我最终会遇到有时甚至导致崩溃的故障。这是视频：https ://drive.google.com/open?id=0B4aMQXnlIOvCUXNjWTVXVkR3NHc 。还有一个：https ://drive.google.com/open?id=0B4aMQXnlIOvCUDJjSEN0bFdqQXc

我的 NSTextStorage 子类中的代码片段：

override func attributesAtIndex(index: Int, effectiveRange range: NSRangePointer) -> [String : AnyObject] {
    return storage.attributesAtIndex(index, effectiveRange: range)
}


override func replaceCharactersInRange(range: NSRange, withString str: String) {
    let delta = str.characters.count - range.length
    beginEditing()
    storage.replaceCharactersInRange(range, withString:str)
    edited([.EditedCharacters, .EditedAttributes], range: range, changeInLength: delta)
    endEditing()
}


override func setAttributes(attrs: [String : AnyObject]!, range: NSRange) {
    beginEditing()
    storage.setAttributes(attrs, range: range)
    edited(.EditedAttributes, range: range, changeInLength: 0)
    endEditing()
}

我的 NSTextView 子类中的代码片段：

override func shouldChangeTextInRange(affectedCharRange: NSRange, replacementString: String?) -> Bool {
    super.shouldChangeTextInRange(affectedCharRange, replacementString: replacementString)
    guard replacementString != nil else { return true }

    if replacementString == "\t" {
        defer {
            let selectedRangesValues = self.selectedRanges
            var selectedRanges = [NSRange]()
            for value in selectedRangesValues {
                selectedRanges.append(value.rangeValue)
            }
            textController.switchToAltAttributesInRange(selectedRanges)
        }
        return false
    }
    return true
}

我的 TextController 中创建和应用替代属性的代码片段：

func switchToAltAttributesInRange(ranges : [NSRange]) {
    // get paragraph indexes from the ranges
    var indexes = [Int]()
    for range in ranges {
        for idx in textStorage.paragraphsInRange(range) {
            indexes.append(idx)
        }
    }

    // change attributes for all the paragraphs in those ranges
    for index in indexes {
        let paragraphRange = textStorage.paragraphRangeAtIndex(index)
        let element = elementAtIndex(index)
        let altElementType = altElementTypeForElementType(element.type)

        // change the attributes
        let newAttributes = paragraphAttributesForElement(type: altElementType.rawValue)
        self.textStorage.beginUpdates()
        self.textStorage.setAttributes(newAttributes, range: paragraphRange)
        self.textStorage.endUpdates()
    }
}

func paragraphAttributesForElement(type typeString: String) -> [String : AnyObject] {
    let elementPreset = elementPresetForType(elementType)

    // set font
    let font = NSFont (name: elementPreset.font, size: CGFloat(elementPreset.fontSize))!

    // set attributes
    let elementAttributes = [NSFontAttributeName: font,
                  NSParagraphStyleAttributeName : paragraphStyleForElementPreset(elementPreset, font: font),
                  NSForegroundColorAttributeName: NSColor.colorFromHexValue(elementPreset.color),
                  NSUnderlineStyleAttributeName : elementPreset.underlineStyle,
              ElementAttribute.AllCaps.rawValue : elementPreset.allCaps]

    return elementAttributes
}

func paragraphStyleForElementPreset(elementPreset : TextElementPreset, font : NSFont) -> NSParagraphStyle {
    let sceneParagraphStyle = NSMutableParagraphStyle()

    let spacing = elementPreset.spacing
    let spacingBefore = elementPreset.spacingBefore
    let headIndent = elementPreset.headIndent
    let tailIndent = elementPreset.tailIndent

    let cFont = CTFontCreateWithName(font.fontName, font.pointSize, nil)
    let fontHeight = CTFontGetDescent(cFont) + CTFontGetAscent(cFont) + CTFontGetLeading(cFont)

    sceneParagraphStyle.paragraphSpacingBefore = CGFloat(spacingBefore)
    sceneParagraphStyle.paragraphSpacing = fontHeight * CGFloat(spacing)
    sceneParagraphStyle.headIndent = ScreenMetrics.pointsFromInches(CGFloat(headIndent))
    sceneParagraphStyle.tailIndent = ScreenMetrics.pointsFromInches(CGFloat(tailIndent))
    sceneParagraphStyle.firstLineHeadIndent = sceneParagraphStyle.headIndent
    sceneParagraphStyle.lineBreakMode = .ByWordWrapping
    return sceneParagraphStyle
}

当我按 Tab 键时，Time Profiler 仪器显示一个高峰值。它说每次按 Tab 键时 NSTextStorage attributesAtIndex 最多需要 40 毫秒。

我检查了：如果我删除 NSParagraphStyle 更改，一切都会变得正常。所以问题是：我应该如何更新段落样式？

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1 回答 1

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嗯......在Apple docs或Google中都没有找到这样的解决方案......刚刚进行了实验，结果证明如果我在调用self.textStorage.setAttributes之后添加textView.display（），一切正常！

更新： setNeedsDisplay(invalidRect) 做得更好，因为您可能只重绘文本视图可见矩形的脏部分

于 2016-04-25T04:31:00.550 回答