英文:
How do I display nil, or make it not display certain instances of a class in a table view?
问题
我有一个文件，其中有一个附加了几个变量的类，基本上我想要能够只显示类的那些具有大于0的数量的部分，而不显示空值。这是非常重要的，因为这是一个较大应用的一部分，如果我这样做，将会导致应用崩溃。
到目前为止，我只是在处理这个单元格。
我的类数组和代码：
var allResources = [m1, m2, m3, m4, m5, m6, m7, m8, m9, m10, m11, m12, m13, m14, m15, m16, m17, m18, m19, m20, m21, m22, m23, m24, m25, m26, m27, m28, m29, m30, m31, m32, m33, m34, m35, m36, m37, m38, m39, m40, m41, m42, p1, p2, p3, p4, p5, p6, p7, p8, p9, p10, p11, p12, p13, p14, p15, p16, p17, p18, p19, p20, f1, f2, f3, f4, f5, f6, f7, f8, f9, f10, f11, f12, f13, f14, f15, f16, f17, f18, f19, f20, w1, w2, w3, w4, w5, w6, w7, w8, w9, w10]
@IBOutlet weak var tableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
// 在加载视图后执行任何额外的设置。
f3.amount += 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return allResources.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "CellID", for: indexPath)
if allResources[indexPath.row].amount > 0 {
cell.textLabel?.text = "\(allResources[indexPath.row].name)"
cell.detailTextLabel?.text = "\(allResources[indexPath.row].amount)"
}
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
allResources.remove(at: 0)
tableView.deleteRows(at: [indexPath], with: .fade)
}
我的类的一部分：
class resource {
var name: String
var type: String
var value: Int
var edible: Bool
var buildingMaterial: Bool
var craftsMaterial: Bool
var toolMaterial: Bool
var amount: Int = 0
init(name: String, type: String, value: Int, edible: Bool, buildingMaterial: Bool, craftsMaterial: Bool, toolMaterial: Bool, amount: Int) {
self.name = name
self.type = type
self.value = value
self.edible = edible
self.buildingMaterial = buildingMaterial
self.craftsMaterial = craftsMaterial
self.toolMaterial = toolMaterial
self.amount = amount
}
}
// 石灰石
var m1 = resource(name: "Limestone", type: "Mineral", value: 1, edible: false, buildingMaterial: true, craftsMaterial: true, toolMaterial: true, amount: 0)
// 花岗岩
var m2 = resource(name: "Granite", type: "Mineral", value: 20, edible: false, buildingMaterial: true, craftsMaterial: true, toolMaterial: false, amount: 0)
英文:
I have a file that has a class with a few variables attached to it, and essentially I want to be able to only display the parts of the class that have an amount higher than 0 without still displaying the empty values. It's very important that I do this without programmatically assigning a new array as this is part of a larger app that would break if I did that
So far I have just been messing with the cell
My class array and code
var allResources = [m1, m2, m3, m4, m5, m6, m7, m8, m9, m10, m11, m12, m13, m14, m15, m16, m17, m18, m19, m20, m21, m22, m23, m24, m25, m26, m27, m28, m29, m30, m31, m32, m33, m34, m35, m36, m37, m38, m39, m40, m41, m42, p1, p2, p3, p4, p5, p6, p7, p8, p9, p10, p11, p12, p13, p14, p15, p16, p17, p18, p19, p20, f1, f2, f3, f4, f5, f6, f7, f8, f9, f10, f11, f12, f13, f14, f15, f16, f17, f18, f19, f20, w1, w2, w3, w4, w5, w6, w7, w8, w9, w10]
@IBOutlet weak var tableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
f3.amount += 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return allResources.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "CellID", for: indexPath)
if allResources[indexPath.row].amount > 0 {
cell.textLabel?.text = "\(allResources[indexPath.row].name)"
cell.detailTextLabel?.text = "\(allResources[indexPath.row].amount)"
}
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
allResources.remove(at: 0)
tableView.deleteRows(at: [indexPath], with: .fade)
}
A part of my class
class resource {
var name: String
var type: String
var value: Int
var edible: Bool
var buildingMaterial: Bool
var craftsMaterial: Bool
var toolMaterial: Bool
var amount: Int = 0
init(name: String, type: String, value: Int, edible: Bool, buildingMaterial: Bool, craftsMaterial: Bool, toolMaterial: Bool, amount: Int) {
self.name = name
self.type = type
self.value = value
self.edible = edible
self.buildingMaterial = buildingMaterial
self.craftsMaterial = craftsMaterial
self.toolMaterial = toolMaterial
self.amount = amount
}
}
//Limestone
var m1 = resource(name: "Limestone", type: "Mineral", value: 1, edible: false, buildingMaterial: true, craftsMaterial: true, toolMaterial: true, amount: 0)
//Granite
var m2 = resource(name: "Granite", type: "Mineral", value: 20, edible: false, buildingMaterial: true, craftsMaterial: true, toolMaterial: false, amount: 0)
答案1
得分: 1
以下是您要翻译的内容：
"It seems you want to filter your array. Usually you would just remove the values you don't need from the allResources array. But if the array is used in a different context you are pretty much left with 1 option here.
Create a new array that contains only the values you want to use. Possible implementation:
var resourcesWithAmount: [resource]
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
f3.amount += 1
resourcesWithAmount = allResources.filter{$0.amount > 0 }
}
and use only this collection as datasource for your tableview:
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return resourcesWithAmount.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "CellID", for: indexPath)
cell.textLabel?.text = "\(resourcesWithAmount[indexPath.row].name)"
cell.detailTextLabel?.text = "\(resourcesWithAmount[indexPath.row].amount)"
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
// this should probably read
// resourcesWithAmount.remove(at: indexpath.row)
resourcesWithAmount.remove(at: 0)
tableView.deleteRows(at: [indexPath], with: .fade)
}
```"
<details>
<summary>英文:</summary>
It seems you want to filter your array. Usually you would just remove the values you don´t need from the `allResources` array. But if the array is used in a different context you are pretty much left with 1 option here.
Create a new array that contains only the values you want to use. Possible implementation:
var resourcesWithAmount: [resource]
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
f3.amount += 1
resourcesWithAmount = allResources.filter{$0.amount > 0 }
}
and use only this collection as datasource for your tableview:
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return resourcesWithAmount.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "CellID", for: indexPath)
cell.textLabel?.text = "\(resourcesWithAmount[indexPath.row].name)"
cell.detailTextLabel?.text = "\(resourcesWithAmount[indexPath.row].amount)"
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
// this should probably read
// resourcesWithAmount.remove(at: indexpath.row)
resourcesWithAmount.remove(at: 0)
tableView.deleteRows(at: [indexPath], with: .fade)
}
</details>
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