I try to learn SOLID principle and i have a problem when I want to subscript an array, it show an error message. but when I try to subscript with arc4random_uniform the error message not show up. can anyone show me what it wrong?
Thread: 1 fatal error: Index out of range
this is my code in Item Class
class Item: NSObject {
var imageName: String
var label: String
init(imageName: String, label: String) {
self.imageName = imageName
self.label = label
super.init()
}
convenience init(list: Bool = false) {
if list {
let imageList = ["milada-vigerova", "david-rodrigo", "quran"]
let labelList = ["Fiqih", "Hadist", "Tafsir"]
// The sortImage and sort label, the error show up
let sortImageName = imageList[imageList.count]
let sortLabel = labelList[labelList.count]
self.init(imageName: sortImageName, label: sortLabel)
} else {
self.init(imageName: "", label: "")
}
}
}
update question. this is another error in appDelegate while fixing the subscript
let itemStore = ItemStore()
let homeController = window?.rootViewController as! HomeController
homeController.itemStore = itemStore
this is my itemStore class
class ItemStore {
var allItems = [Item]()
@discardableResult func createItem() -> Item {
let newItem = Item(list: true)
allItems.append(newItem)
return newItem
}
init() {
for _ in 0..<3 {
createItem()
}
}
}
Index in an array starts at 0 so a 3 element array has indexes 0,1 and 2 and count
= 3 so to access the last item of an array using count
you need to do [someArray.count -1]
if list {
let imageList = ["milada-vigerova", "david-rodrigo", "quran"]
let labelList = ["Fiqih", "Hadist", "Tafsir"]
// The sortImage and sort label, the error show up
let sortImageName = imageList[imageList.count - 1]
let sortLabel = labelList[labelList.count - 1]
...
Notice that arc4random_uniform(n)
returns a value between 0 and n-1
so doing arc4random_uniform(imageList.count)
for instance will work perfectly
imageList have 3 items, and lastest item at index 2, similar with labelList , modify code at two lines:
// The sortImage and sort label, the error show up
let sortImageName = imageList[imageList.count - 1]
let sortLabel = labelList[labelList.count - 1]
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.