ForEach loop inside a button action in SwiftUI? - ios

Question

I understand that a ForEach loop is typically used to display a view. When I put a ForEach loop inside the action button it pretty much tells me Button action cannot conform to the view protocol. So how can I use a loop to make the button carry out multiple actions?
struct SomeView: View {
var newExercises = [NewExercise]()
var finalExercises = [Exercise]()
var body: some View {
Button(action: {
ForEach(newExercises) { newExercise in
//.getExercise() returns an Exercise object
finalExercises.append(newExercise.getExercise())
}
}) {
Text("Done")
}
}
}
I want the button to add an Exercise (by calling .getExercise()) to the finalExercises array for each newExercise in the newExercises array.
How can I go about doing this?

Answer 1

The new SwiftUI ForEach statement returns a View for each Element of an Array. For your code, you simply need to run a Void, Array<Exercise>.append(newElement: Exercise) not get multiple View's, so you can use a for loop, map, or Array.forEach(body: (_) throws -> Void).
If the order in which the newExercises are appended matters, the most elegant solution will be mapping each NewExercise of finalExercises to a Exercise, and appending the resulting Array<Exercise>, with Array<Exercise>.append(contentsOf: Sequence).
struct SomeView: View {
#State var newExercises = [NewExercise]()
#State var finalExercises = [Exercise]()
var body: some View {
Button(action: {
self.finalExercises.append(contentsOf:
self.newExercises.map { newExercise -> Exercise in
newExercise.getExercise()
}
)
}) {
Text("Done")
}
}
}
If the order in which the newExercises are appended does not matter, you can call Array<Exercise>.append(newElement: Exercise) from newExcercises.forEach, which is different than a SwiftUI ForEach statement:
struct SomeView: View {
#State var newExercises = [NewExercise]()
#State var finalExercises = [Exercise]()
var body: some View {
Button(action: {
self.newExercises.forEach { newExercise in
self.finalExercises.append(newExercise.getExercise())
}
}) {
Text("Done")
}
}
}
The way to complete what you want with a for loop would be simple, but less elegant:
struct SomeView: View {
#State var newExercises = [NewExercise]()
#State var finalExercises = [Exercise]()
var body: some View {
Button(action: {
for newExercise in self.newExercises {
self.finalExercises.append(newExercise.getExercise())
}
}) {
Text("Done")
}
}
}