Is it possible to override a view modifier from a custom view? - swift

Question

Is it possible to override your own default modifier on a custom View? If not, is there any fancy way to adjust this without using an init?
Example
struct MainView: View {
var body: some View {
CustomView()
.font(.custom(weight: .medium, fontSize: 28)) // I want the custom view to change its' "sub"-font and use this modifier instead of using .footnote font.
}
}
struct CustomView: View {
var body: some View {
VStack {
Divider()
Text("Random")
.font(.footnote)
}
}
}
One solution is just to add an Font property in the CustomView init and use it inside the viewModifier like below. But would be gladly to know if it's possible to change it from its' parent viewModifier! I might just end up with using the solution below if it's not possible.
struct CustomView: View {
let customFont: Font = .callout
var body: some View {
VStack {
Divider()
Text("Random")
.font(customFont)
}
}
}

Answer 1

To make your MainView work we can use extension with custom implementation of font modifier, explicit for CustomView.
Here is a demo of approach (prepared & tested with Xcode 12.5 / iOS 14.5)
CustomView()
.font(.custom("Arial", size: 28, relativeTo: .caption))
struct CustomView: View {
private var customFont: Font = .footnote
var body: some View {
VStack {
Divider()
Text("Random")
.font(customFont)
}
}
}
extension CustomView {
func font(_ font: Font) -> some View {
var updatedView = self // make writable
updatedView.customFont = font // update in copy
return updatedView // return updated with external font
}
}

Answer 2

You can create one Appearance class and mention all the style property for your subview component and make an own function for all property inside the view.
Here is the demo code.
CustomViewAppearance
class CustomViewAppearance {
var customFont: Font = .footnote
var textColor: Color = .red
}
CustomView and property function.
struct CustomView: View {
private var appearance = CustomViewAppearance()
var body: some View {
VStack {
Divider()
Text("Random")
.font(appearance.customFont)
.foregroundColor(appearance.textColor)
}
}
}
extension CustomView {
func font(_ font: Font) -> some View {
self.appearance.customFont = font
return self
}
func foregroundColor(_ color: Color) -> some View {
self.appearance.textColor = color
return self
}
}
--
You can also set direct Appearance.
extension CustomView {
func appearance(_ appearance: CustomViewAppearance) -> some View {
var selfView = self
selfView.appearance = appearance
return selfView
}
}
struct MainView: View {
var body: some View {
CustomView()
.appearance(customStyle())
}
func customStyle() -> CustomViewAppearance {
let appearance = CustomViewAppearance()
appearance.customFont = .largeTitle
appearance.textColor = .yellow
return appearance
}
}