iOS：如何对齐诸如whatsapp聊天消息标签和时间标签之类的标签？ [英] Ios : How to align labels like whatsapp chat message label and time label?

问题描述

在whatsapp中，如果消息很短，则文本和时间在同一行中。
如果消息很长，则时间在右下角-文本正上方。

In whatsapp, if the message is very short, the text and time are in the same row. If the message is long, the time is in the bottom right corner - the text coming above it.

如何在Ios中使用Storyboard实现此目标

How can i achieve this using Storyboard in Ios

推荐答案

尝试使用类似这样的方法来定义最后的行宽（也许您将不得不对文本容器进行一些调整）：

Try using something like this to define last line width (Maybe you'll have to tweak text container a bit more for your case):

public func lastLineMaxX(message: NSAttributedString, labelWidth: CGFloat) -> CGFloat {
    // Create instances of NSLayoutManager, NSTextContainer and NSTextStorage
    let labelSize = CGSize(width: bubbleWidth, height: .infinity)
    let layoutManager = NSLayoutManager()
    let textContainer = NSTextContainer(size: labelSize)
    let textStorage = NSTextStorage(attributedString: message)

    // Configure layoutManager and textStorage
    layoutManager.addTextContainer(textContainer)
    textStorage.addLayoutManager(layoutManager)

    // Configure textContainer
    textContainer.lineFragmentPadding = 0.0
    textContainer.lineBreakMode = .byWordWrapping
    textContainer.maximumNumberOfLines = 0

    let lastGlyphIndex = layoutManager.glyphIndexForCharacter(at: message.length - 1)
    let lastLineFragmentRect = layoutManager.lineFragmentUsedRect(forGlyphAt: lastGlyphIndex,
                                                                  effectiveRange: nil)

    return lastLineFragmentRect.maxX
}

然后，您可以决定是否有足够的地方来约会标签是否在最后一行

Then you can decide if there is enough place for your date label in the last line or not

用法示例：

// you definitely have to set at least the font to calculate the result
// maybe for your case you will also have to set other attributes
let attributedText = NSAttributedString(string: self.label.text, 
                                        attributes: [.font: self.label.font])
let lastLineMaxX = lastLineMaxX(message: attributedText, 
                                labelWidth: self.label.bounds.width)

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