Make TextEditor dynamic height SwiftUI - string

Question

I'm trying to create a growing TextEditor as input for a chat view.
The goal is to have a box which expands until 6 lines are reached for example. After that it should be scrollable.
I already managed to do this with strings, which contain line breaks \n.
TextEditor(text: $composedMessage)
.onChange(of: self.composedMessage, perform: { value in
withAnimation(.easeInOut(duration: 0.1), {
if (value.numberOfLines() < 6) {
height = startHeight + CGFloat((value.numberOfLines() * 20))
}
if value.numberOfLines() == 0 || value.isEmpty {
height = 50
}
})
})
I created a string extension which returns the number of line breaks by calling string.numberOfLines() var startHeight: CGFloat = 50
The problem: If I paste a text which contains a really long text, it's not expanding when this string has no line breaks. The text get's broken in the TextEditor.
How can I count the number of breaks the TextEditor makes and put a new line character at that position?

Answer 1

Here's a solution adapted from question and answer,
struct ChatView: View {
#State var text: String = ""
// initial height
#State var height: CGFloat = 30
var body: some View {
ZStack(alignment: .topLeading) {
Text("Placeholder")
.foregroundColor(.appLightGray)
.font(Font.custom(CustomFont.sofiaProMedium, size: 13.5))
.padding(.horizontal, 4)
.padding(.vertical, 9)
.opacity(text.isEmpty ? 1 : 0)
TextEditor(text: $text)
.foregroundColor(.appBlack)
.font(Font.custom(CustomFont.sofiaProMedium, size: 14))
.frame(height: height)
.opacity(text.isEmpty ? 0.25 : 1)
.onChange(of: self.text, perform: { value in
withAnimation(.easeInOut(duration: 0.1), {
if (value.numberOfLines() < 6) {
// new height
height = 120
}
if value.numberOfLines() == 0 || value.isEmpty {
// initial height
height = 30
}
})
})
}
.padding(4)
.overlay(
RoundedRectangle(cornerRadius: 8)
.stroke(Color.appLightGray, lineWidth: 0.5)
)
}
}
And the extension,
extension String {
func numberOfLines() -> Int {
return self.numberOfOccurrencesOf(string: "\n") + 1
}
func numberOfOccurrencesOf(string: String) -> Int {
return self.components(separatedBy:string).count - 1
}
}

Answer 2

I found a solution!
For everyone else trying to solve this:
I added a Text with the same width of the input field and then used a GeometryReader to calculate the height of the Text which automatically wraps. Then if you divide the height by the font size you get the number of lines.
You can make the text field hidden (tested in iOS 14 and iOS 15 beta 3)

Answer 3

If you're looking for an iOS 15 solution, I spent a while and figured it out. I didn't want to have to resort to UIKit or ZStacks with overlays or duplicative content as a "hack". I wanted it to be pure SwiftUI.
I ended up creating a separate struct that I could reuse anywhere I needed it, as well as add additional parameters in my various views.
Here's the struct:
struct FieldMultiEntryTextDynamic: View {
var text: Binding<String>
var body: some View {
TextEditor(text: text)
.padding(.vertical, -8)
.padding(.horizontal, -4)
.frame(minHeight: 0, maxHeight: 300)
.font(.custom("HelveticaNeue", size: 17, relativeTo: .headline))
.foregroundColor(.primary)
.dynamicTypeSize(.medium ... .xxLarge)
.fixedSize(horizontal: false, vertical: true)
} // End Var Body
} // End Struct
The cool thing about this is that you can have placeholder text via an if statement and it supports dynamic type sizes.
You can implement it as follows:
struct MyView: View {
#FocusState private var isFocused: Bool
#State private var myName: String = ""
var body: some View {
HStack(alignment: .top) {
Text("Name:")
ZStack(alignment: .trailing) {
if myName.isEmpty && !isFocused {
Text("Type Your Name")
.font(.custom("HelveticaNeue", size: 17, relativeTo: .headline))
.foregroundColor(.secondary)
}
HStack {
VStack(alignment: .trailing, spacing: 5) {
FieldMultiEntryTextDynamic(text: $myName)
.multilineTextAlignment(.trailing)
.keyboardType(.alphabet)
.focused($isFocused)
}
}
}
}
.padding()
.background(.blue)
}
}
Hope it helps!