如何根据UITextView动态调整Xib的大小

Question

I am using auto layout.

• I am loading UIView from xib.
• All elements have static size except UITextView .
• I've disabled scroll on UITextView
• UITextView is filled with the text of different size on ViewDidLoad() . So it can be 1 line or 7 lines there for example.

I am loading this UIView with the following method:

fileprivate func setTableHeaderView() {
    guard let _headerView = UINib(nibName: "TableHeaderView",
                                 bundle: nil).instantiate(withOwner: self, options: nil)[0] as? UIView else { return }

    tableView.tableHeaderView = UIView(frame:
        CGRect(x: 0, y: 0, width: tableView.frame.width, height: _headerView.frame.size.height))

    configureViewController() // here I set the text for UITextView
    tableView.tableHeaderView?.addSubview(_headerView)
}

When I load this UIView the height is always the same both before and after layoutSubviews . Actually the size always is equal to the initial size of the xib that is set in the Size Inspector of XCode.

I want to UITextView to fit the text size and to have different xib UIView size that will depend on the size of UITextView + all other elements + constraints.

I've tried different ways to implement this but but none did not help. What I've tried:

• to set constraints in different ways
• to call layoutSubviews() forcibly and check the size of the resulted UIView
• to check size of UIView after viewDidLayoutSubviews
• translatesAutoresizingMaskIntoConstraints = true with autoresizingMask = .flexibleHeight

Is it possible to implement this idea in such way?

Answer 1

Try to override viewDidLayoutSubviewsMethod

override func viewDidLayoutSubviews() {
    super.viewDidLayoutSubviews()

    // Dynamic sizing for the header view
    if let headerView = tableView.tableHeaderView {
        let height = headerView.systemLayoutSizeFittingSize(UILayoutFittingCompressedSize).height
        var headerFrame = headerView.frame

        // If we don't have this check, viewDidLayoutSubviews() will get
        // repeatedly, causing the app to hang.
        if height != headerFrame.size.height {
            headerFrame.size.height = height
            headerView.frame = headerFrame
            tableView.tableHeaderView = headerView
        }
    }
}