如何根据内容动态设置表格视图的高度，但它应与底部按钮保持最小距离？

Question

I have UITableview as shown in the image and this is at a distance of 20 points from the bottom button. So it has no height constraint as of now, it is just pinned to with the top view at 0 margin and 20 from the bottom button.

Now what I want is to adjust the frame of this tableview if there are only 2-3 cells or to 0 height if there are no cells.

I am not really sure about the order in which the updateLayoutconstraints and other related methods have to be called.All I am pretty sure about is that I will have to have a height constraint on the tableview which will be connected via code to the xib and I will have to update it once the reloadData on tableView is called.

Answer 1

You are already thinking in the right direction.

Here are the steps to make it work:

1. Change the button top constraint relation to greaterThanOrEqual
2. Add a tableView height constraint as @IBOutlet to your ViewController. Change this constraint's priority from Required to High to avoid an Auto Layout error when the contentSize is greater than the available height
3. Override updateViewConstraints() in your UIViewController and set the height constraint's constant to tableView.contentSize.height
4. Call updateViewConstraints() whenever the number of rows changes

Answer 2

问题是您的UIButton的按钮约束是“相等的”，当表格视图高度减小按钮将改变y的位置并上升时，您可以将其更改为“大于”