I apply ".animation (.easeIn)" but it is deprecated. tells me: animation 'has been deprecated in iOS 15.0: use instead with Animation or animation (: value :), but animation (: value :) I don't know which value I need to pass. I can't create animations that start slowly. Can you please help me understand how I can properly use animation (_: value :) to make animation work? I have to create the animation that when I move the slider, the images slowly recompose in space according to how much they are enlarged or reduced. thank you.

'''

import SwiftUI

struct GalleryView: View {
    // MARK: - PROPERTIES
    
    @State private var selectedAnimal: String = "lion"
    
    
    let animals: [Animal] = Bundle.main.decode("animals.json")
    let haptics = UIImpactFeedbackGenerator(style: .medium)
    
    @State private var gridLayout: [GridItem] = [GridItem(.flexible())]
    @State private var gridColumn: Double = 3.0
    
    func gridSwitch() {
        gridLayout = Array(repeating: .init(.flexible()), count: Int(gridColumn))
    }
    
    // MARK: - BODY
    var body: some View {
        ScrollView(.vertical, showsIndicators: false) {

            VStack(alignment: .center, spacing: 30) {
                // MARK: - IMAGE
                
                Image(selectedAnimal)
                    .resizable()
                    .scaledToFit()
                    .clipShape(Circle())
                    .overlay(Circle().stroke(Color.white, lineWidth: 8))
                
                // MARK: - SLIDER
                
                Slider(value: $gridColumn, in: 2...4, step: 1) // se aumento il valore nello slider ci saranno più sezioni
                    .padding(.horizontal)
                    .onChange(of: gridColumn, perform: { value in
                        gridSwitch()
                    })
                
                // MARK: - GRID
                LazyVGrid(columns: gridLayout, alignment: .center, spacing: 10) {
                    ForEach(animals) { item in
                        Image(item.image)
                            .resizable()
                            .scaledToFit()
                            .clipShape(Circle())
                            .overlay(Circle().stroke(Color.white, lineWidth: 1))
                            .onTapGesture {
                            selectedAnimal = item.image
                                haptics.impactOccurred()
                        }
                        
                    } //: LOOP

                } //: GRID
                .animation(.easeIn) 
                .onAppear(perform: {
                    gridSwitch()
                })
            } //: VSTACK
            .padding(.horizontal, 10)
            .padding(.vertical,50)
        } //: SCROLL
        .frame(maxWidth: .infinity, maxHeight: .infinity)
        .background(MotionAnimationView())
    }
}

// MARK: - PREVIEW

struct GalleryView_Previews: PreviewProvider {
    static var previews: some View {
        GalleryView()
    }
}

CodePudding user response：

As the error says, .animation() is deprecated, with iOS 15, you need to use .animation(value:) now. where the value is the binding that you want your animation to be triggered, in your case, I assume it is selectedAnimal.

Applying this would be something like

VStack {
}
.animation(.easeIn, value: selectedAnimal) 

As discussed in comments, if you want your gridLayout to be animatable, it is a little bit more tricky. Because Arrays has to be Equatable if you want them to be animatable, since extending the GridItem is not a good solution, I came up with this:

delete your .animation method change your gridSwitch function with this:

struct GalleryView: View {
// ... irrelevant code

@State private var isGridChanged = false

func gridSwitch() {
        if (isGridChanged) {
            withAnimation {
                gridLayout = Array(repeating: .init(.flexible()), count: Int(gridColumn))
            }
        }
        else {
            gridLayout = Array(repeating: .init(.flexible()), count: Int(gridColumn))
            isGridChanged = true
        }
    }

isGridChanged is required because as you're changing your gridLayout when your View is initialized, it causes a weird bug that everything is getting scaled down when app launches because of withAnimation.