I am new to swift and creating a music theory app. To make it more readable, I would like the colour of each topic to change depending on the difficulty (ie 1 = green, 2 = orange, 3 = red). However, I cannot reference another variable (difficulty) when initialising the variable 'colour' using my function. I'm not sure how to fix this error: "cannot find 'difficulty' in scope" on lines 36-39. Thanks
You cannot do that. But you don't need. colour is computed, so no need to pass as a parameter in Topic.
You can do this:
struct Topic: Identifiable {
var id: UUID
var name: String
var difficulty: Int
var colour: Color?
init(id: UUID, name: String, difficulty: Int) {
self.id = id
self.name = name
self.difficulty = difficulty
self.colour = changeColour(difficulty: difficulty)
func changeColour(difficulty: Int) -> Color {
if difficulty == 1 {
return .green
} else if difficulty == 2 {
return .orange
} else {
return .red
}
}
}
}
var topics: [Topic] = [Topic(id: UUID(), name: "Major Scales", difficulty: 1),
Topic(id: UUID(), name: "Minor Scales", difficulty: 3),
Topic(id: UUID(), name: "Major Arpeggios", difficulty: 2),
Topic(id: UUID(), name: "Minor Arpeggios", difficulty: 3)]
print(topics[0].name, topics[0].colour!)
print(topics[1].name, topics[1].colour!)
print(topics[2].name, topics[2].colour!)
print(topics[3].name, topics[3].colour!)
You get:
Major Scales green
Minor Scales red
Major Arpeggios orange
Minor Arpeggios red
Note that changeColour may be defined inside init or outside:
struct Topic: Identifiable {
var id: UUID
var name: String
var difficulty: Int
var colour: Color?
init(id: UUID, name: String, difficulty: Int) {
self.id = id
self.name = name
self.difficulty = difficulty
self.colour = changeColour(difficulty: difficulty)
}
func changeColour(difficulty: Int) -> Color {
if difficulty == 1 {
return .green
} else if difficulty == 2 {
return .orange
} else {
return .red
}
}
}
