Growing text input view - swift examples

Question

I am trying un the past two days to implement a UITextView that grows as the user types. Like whats-app does.

I've found examples here with textViewDidChange but that didn't really work as it needs to not only grow but also move upwards. And as the textview sits inside a view that also holds the send button, they both have to grow upwards.

Also found some other frameworks.

https://github.com/slackhq/SlackTextViewController - looks really cool and may do everything I need but I found no examples of it running swift. The sample project provided I could not run.

https://github.com/MatejBalantic/MBAutoGrowingTextView - could not really get it to work upwards.

I am looking for some help on how to implement that using SWIFT or maybe a sample project of the SLACK one running on swift that is not the sample project on github. Or maybe a bit of code showing how to link the UITextView to the Slack class and make it work inside a viewController class.

Answer 1

Here's what I'm currently using for my inputAccessoryView.

I have a toolbar that holds the UITextView and send button and listens to textViewDidChange events like so:

func textViewDidChange(_ textView: UITextView) {
    let oldHeight = textView.height
    let maxHeight: CGFloat = 100.0 //beyond this value the textView will scroll
    var newHeight = min(textView.sizeThatFits(CGSize(width: textView.frame.width, height: CGFloat.greatestFiniteMagnitude)).height, maxHeight)
    newHeight = ceil(newHeight)
    if newHeight != oldHeight {
        textView.frame.size.height = max(newHeight, barHeight)
        updateHeight(height: newHeight)
    }
}

The goal here is to set the new textView height. Then I update the toolbar height as well

public func updateToolBarHeight(height: CGFloat) {
    for constraint in constraints {
        if constraint.firstAttribute == NSLayoutAttribute.height && constraint.firstItem as! NSObject == self {
            constraint.constant = max(barHeight, height)
        }
    }
    setNeedsUpdateConstraints()
    sendButton.origin.y = max(0, height - barHeight)
}

barHeight is my default toolbar height (set to 50.0). and I also update my sendButton position to stay at the bottom of the toolbar.