Ios 导航栏中标题为阿拉伯语的问题

我对此功能有问题：

    func setTitle(title:String, subtitle:String) -> UIView {
    let titleLabel = UILabel(frame: CGRect(x:0, y:-5, width:0, height:0))

    titleLabel.backgroundColor = UIColor.clear
    titleLabel.textColor = UIColor.gray
    titleLabel.font = UIFont.boldSystemFont(ofSize: 17)
    titleLabel.text = title
    titleLabel.sizeToFit()

    let subtitleLabel = UILabel(frame: CGRect(x:0, y:18, width:0, height:0))
    subtitleLabel.backgroundColor = UIColor.clear
    subtitleLabel.textColor = UIColor.black
    subtitleLabel.font = UIFont.systemFont(ofSize: 12)
    subtitleLabel.text = subtitle
    subtitleLabel.sizeToFit()

    let titleView = UIView(frame: CGRect(x:0, y:0, width:max(titleLabel.frame.size.width, subtitleLabel.frame.size.width), height:30))
    titleView.addSubview(titleLabel)
    titleView.addSubview(subtitleLabel)

    let widthDiff = subtitleLabel.frame.size.width - titleLabel.frame.size.width

    if widthDiff > 0 {
        var frame = titleLabel.frame
        frame.origin.x = widthDiff / 2
        titleLabel.frame = frame.integral
    } else {
        var frame = subtitleLabel.frame
        frame.origin.x = abs(widthDiff) / 2
        titleLabel.frame = frame.integral
    }

    return titleView

}

//使用： self.navigationItem.titleView=setTitle（“标题”、“副标题”）

//资料来源：

如上图所示，无论何时有人用阿拉伯语写作[picture 2]，标题都会被弄乱，但如果有人用英语写作[picture 1]。标题的标签将保持完好

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提前谢谢。

我用阿拉伯语和英语单词的所有组合运行了代码，并在代码中发现了问题。看看吧

    if widthDiff > 0 {
        var frame = titleLabel.frame
        frame.origin.x = widthDiff / 2
        titleLabel.frame = frame.integral
    } else {
        var frame = subtitleLabel.frame
        frame.origin.x = abs(widthDiff) / 2
        titleLabel.frame = frame.integral /* subtitleLabel.frame = frame.integral */
    }