SwiftUI Gists

SwiftUI Components & Extension that saves iOSDev time.
### UIKit is **EVENT-Driven** framework - We could reference each view in the hierarchy, update its appearance when the view is loaded or as a reaction on an event.
### SwiftUI is **Declarative, State Driven** framework - We cannot reference any view in the hierarchy, neither can we directly mutate a view as a reaction to an event. 
Instead, we mutate the state bound to the view. Delegates, target-actions, responder chain, KVO .. replaced with Closures & bindings.

☢️ A workaround calculated the height of ScrollView

  @State var heightCalculated = 0.0

  var body: some View {

    ScrollView {
      ForEach(0..<10) { i in
        Text("\(i)")
      }
      .background(
        GeometryReader { proxy in
          Color.clear.onAppear { 
            heightCalculated = proxy.size.height
            debugPrint(proxy.size.height)
          }
        }
      )

    }
    .frame(height: heightCalculated)
  }

To make Content view as parameter. A better way to build Generic views.

struct ContainerView<Content: View>: View {
  @ViewBuilder var content: Content
    
  var body: some View {
    content
  }
}


// Usage
ContainerView{
  ...
}

Debugging:

1. let _ = Self._printChanges() print statement to trace view lifecycle
2. let _ = print("Update XYZView") We use this print to trace whether the body of Particular view (eg. SpyView) is executed or not.

ref: https://sarunw.com/posts/how-to-do-print-debugging-in-swiftui/

To make fullscreen view to fill entire screen:

ZStack {
   Text("Hello").background(.yellow)
}
.frame(maxWidth: .infinity, maxHeight: .infinity) // this is important
.background(.blue)