Question

我有一个视图控制器，我有一个UIImage和UIlabels。此UIimage - 从服务器加载图像，UIlabel文本从数据库中定义的字段中获取值。现在，在一些记录中，我们在服务器上没有图像并且是空白的，但总会有UILabel值。因此，如果我们没有图像价值，我们如何删除UIImage并带上标签（如屏幕截图所示）。

在第一个截图中，我们有图像，所以很好，但第二个截图我们只有文字，并希望带来文本。有一个简单的方法吗？

另外，如果我们在高度和宽度方面有各种尺寸的图像，那么我们如何从服务器获取应用程序上加载的图像的实际尺寸

第一个截图

第二个截图

代码：

   private func checkImage(_ imageString:String)
{
    self.imageUI.layoutIfNeeded()
    if imageString.characters.count >= 2
    {
        if imageString != "<null>"
        {
            let url = NSURL(string:"http://www.xyz.com.au/images/"+imageString)

            let data = NSData(contentsOf:url! as URL)
            if data != nil
            {
                imageUI.image = UIImage(data:data! as Data) //= UIImage(data:data!)
                //imageUI.sizeToFit()



                let data = NSData(contentsOf: url as! URL)
                let Image = UIImage(data: data as! Data)!

            DispatchQueue.main.async {
                if data != nil
                {
                    // We've received valid image.
                    // Find the height & Width of received image and update the image-view's height constraint.
                     imageUI.image = data!.size.height

                }
                else
                {
                    // Sorry,The received image is invalid,Need to hide Image View,So make the Image-view height constraint's constant to 0 which eventually hides it self and pulls that below label up!
                    imageUI.constraints = 0
                }
            }

            }

        }
        else
        {
            //logoImageView.image = UIImage(named: "error-404")
        }
    }
    else
    {
        //logoImageView.image = UIImage(named: "error-404")
    }
}

Answer 1

你可以给它高度约束并将其设置为0（所需优先级，先禁用它，在需要时再次启用）如果图像/标签为零，请记住使其他相关约束更低优先级

Answer 2

Try this,

    // 1. Get a reference to your image view's height constraint from story board to View controller.
    // Assume "constraintImageViewHeight" is the object name of the IBOutlet of image view's height constraint.

    // 2. In Web service completion block,Check for received image is nil/null
    // Assume "imgRecieved" is the object name of UIImage converted from response received.

    DispatchQueue.main.async {
        if imgRecieved != nil
        {
            // We've received valid image.
            // Find the height & Width of received image and update the image-view's height constraint.
            constraintImageViewHeight.constant = imgRecieved!.size.height
        }
        else
        {
            // Sorry,The received image is invalid,Need to hide Image View,So make the Image-view height constraint's constant to 0 which eventually hides it self and pulls that below label up!
            constraintImageViewHeight.constant = 0
        }
    }

Check this out for more information.

Hope that helps!

如果数据为空，我们如何替换/删除元素

第一个截图

第二个截图

2 个答案: