使用NSLayoutManager方法来计算文本容器中占位符标记的位置,我将这些点转换为CGRects,然后将排除路径转换为文本字段周围的文本.这就是这样的：

func createAndAssignExclusionPathsForInputTextFields () {

    var index = 0
    let textFieldCount = self.textFields.count

    var exclusionPaths : [UIBezierPath] = []

    while index < textFieldCount {

        let textField : AgreementTextField = self.textFields[index]

        let location = self.calculatePositionOfPlaceholderAtIndex(index)
        let size = textField.intrinsicContentSize()
        textField.frame = CGRectMake(location.x,location.y,size.width,size.height)

        exclusionPaths.append(textField.exclusionPath())

        index = index + 1
    }

    self.textContainer.exclusionPaths = exclusionPaths
}

// …

func calculatePositionOfPlaceholderAtIndex(textIndex : NSInteger) -> CGPoint {

    let layoutManager : NSLayoutManager = self.textContainer.layoutManager!

    let delimiterRange = self.indices[textIndex]
    let characterIndex = delimiterRange.location
    let glyphRange = self.layoutManager.glyphRangeForCharacterRange(delimiterRange,actualCharacterRange:nil)
    let glyphIndex = glyphRange.location
    let rect = layoutManager.lineFragmentRectForGlyphAtIndex(glyphIndex,effectiveRange: nil,withoutAdditionalLayout: true)

    let remainingRect : UnsafeMutablePointer<CGRect> = nil

    let textContainerRect = self.textContainer.lineFragmentRectForProposedRect(rect,atIndex: characterIndex,writingDirection: .LeftToRight,remainingRect: remainingRect)

    let position = CGPointMake(textContainerRect.origin.x,textContainerRect.origin.y)

    return position
}

在这一点上,我有三个问题：

>一旦我将一个排除路径分配给了textContainer,其他占位符的计算字形位置现在都是错误的.
> calculatePositionOfPlaceholderAtIndex方法给我很好的y值,但是x值都是0.
>我还没有成功地隐藏占位符令牌.

所以,为了解决我的列表中的第一个问题,我尝试添加排除路径,然后再计算下一个,通过更改createAndAssignExclusionPathsForInputTextFields：

func createAndAssignExclusionPathsForInputTextFields () {

    var index = 0
    let textFieldCount = self.textFields.count

    while index < textFieldCount {

        let textField : AgreementTextField = self.textFields[index]

        let location = self.calculatePositionOfPlaceholderAtIndex(index)
        let size = textField.intrinsicContentSize()
        textField.frame = CGRectMake(location.x,size.height)

        self.textContainer.exclusionPaths.append(textField.exclusionPath())

        index = index + 1
    }
}

现在,我的计算头寸全都返回0,0不是我们想要的.添加排除路径可以理解,使计算的位置无效,但为每个rect方法获得0,0没有帮助.

在添加排除路径或隐藏字形后,如何让布局管理器重新计算屏幕上字形的位置？

编辑：每阿兰T答案,我没有运气尝试以下：

func createAndAssignExclusionPathsForInputTextFields () {

    var index = 0
    let textFieldCount = self.textFields.count

    var exclusionPaths : [UIBezierPath] = []

    while index < textFieldCount {

        let textField : AgreementTextField = self.textFields[index]

        let location = self.calculatePositionOfPlaceholderAtIndex(index)
        let size = textField.intrinsicContentSize()
        textField.frame = CGRectMake(location.x,size.height)

        exclusionPaths.append(textField.exclusionPath())
        self.textContainer.exclusionPaths = exclusionPaths

        self.layoutManager.ensureLayoutForTextContainer(self.textContainer)
        index = index + 1
    }

    self.textContainer.exclusionPaths = exclusionPaths
}