如何从 UILabel 中删除可选文本
问题描述 投票：0回答：3
运行应用程序时，我尝试删除
OptionalUILabelOptional重要的是，我从
JSONStructibuOptional?JSONDecoderSwift.DecodingError.Context(codingPath: [_JSONKey(stringValue: "索引 23", intValue: 23), CodingKeys(stringValue: "ibu", intValue: nil)], debugDescription: "预期为 Double 值，但发现为 null。", 底层错误：无））
我该如何解决这个问题？
应用图片：
模型文件夹：
struct Cerveja:Decodable{
let name:String
let image_url:String
let description:String
let tagline:String
let abv:Double
let ibu:Double? //This one that I got the "Optional" written in the UILabel
//If I remove the "?" I got the error below
}
查看文件夹 - 详细信息屏幕：
var item:Cerveja?
override func viewDidLoad() {
super.viewDidLoad()
labelName.text = item?.name
labelDescricao.text = item?.description
labelAmargor.text = "\(String(describing: item!.ibu))"
labelTeorAlc.text = "\(item!.abv)"
let resource = ImageResource(downloadURL: URL(string: "\(item?.image_url ?? "")")!, cacheKey: item?.image_url)
imageDetail.kf.setImage(with: resource)
}
网络文件夹：
func getApiData(completion: @escaping ([Cerveja]) -> ()){
guard let urlString = URL(string: "https://api.punkapi.com/v2/beers") else {
print("URL Error")
return
}
Alamofire.request(urlString).responseJSON { response in
if response.data == response.data{
do{
let decoder = try JSONDecoder().decode([Cerveja].self, from: response.data!)
completion(decoder)
}catch{
print(error)
}
}else{print("API Response is Empty")}
}
}
JSON：
[
{
"id": 1,
"name": "Buzz",
"tagline": "A Real Bitter Experience.",
"first_brewed": "09\/2007",
"description": "A light, crisp and bitter IPA brewed with English and American hops. A small batch brewed only once.",
"image_url": "https:\/\/images.punkapi.com\/v2\/keg.png",
"abv": 4.5,
"ibu": 60,
"target_fg": 1010,
"target_og": 1044,
"ebc": 20,
"srm": 10,
"ph": 4.4,
"attenuation_level": 75,
"volume": {
"value": 20,
"unit": "liters"
},
"boil_volume": {
"value": 25,
"unit": "liters"
},
"method": {
"mash_temp": [
{
"temp": {
"value": 64,
"unit": "celsius"
},
"duration": 75
}
],
"fermentation": {
"temp": {
"value": 19,
"unit": "celsius"
}
},
"twist": null
},
"ingredients": {
"malt": [
{
"name": "Maris Otter Extra Pale",
"amount": {
"value": 3.3,
"unit": "kilograms"
}
},
{
"name": "Caramalt",
"amount": {
"value": 0.2,
"unit": "kilograms"
}
},
{
"name": "Munich",
"amount": {
"value": 0.4,
"unit": "kilograms"
}
}
],
"hops": [
{
"name": "Fuggles",
"amount": {
"value": 25,
"unit": "grams"
},
"add": "start",
"attribute": "bitter"
},
{
"name": "First Gold",
"amount": {
"value": 25,
"unit": "grams"
},
"add": "start",
"attribute": "bitter"
},
{
"name": "Fuggles",
"amount": {
"value": 37.5,
"unit": "grams"
},
"add": "middle",
"attribute": "flavour"
},
{
"name": "First Gold",
"amount": {
"value": 37.5,
"unit": "grams"
},
"add": "middle",
"attribute": "flavour"
},
{
"name": "Cascade",
"amount": {
"value": 37.5,
"unit": "grams"
},
"add": "end",
"attribute": "flavour"
}
],
"yeast": "Wyeast 1056 - American Ale\u2122"
},
"food_pairing": [
"Spicy chicken tikka masala",
"Grilled chicken quesadilla",
"Caramel toffee cake"
],
"brewers_tips": "The earthy and floral aromas from the hops can be overpowering. Drop a little Cascade in at the end of the boil to lift the profile with a bit of citrus.",
"contributed_by": "Sam Mason <samjbmason>"
},
{
"id": 2,
"name": "Trashy Blonde",
"tagline": "You Know You Shouldn't",
"first_brewed": "04\/2008",
"description": "A titillating, neurotic, peroxide punk of a Pale Ale. Combining attitude, style, substance, and a little bit of low self esteem for good measure; what would your mother say? The seductive lure of the sassy passion fruit hop proves too much to resist. All that is even before we get onto the fact that there are no additives, preservatives, pasteurization or strings attached. All wrapped up with the customary BrewDog bite and imaginative twist.",
"image_url": "https:\/\/images.punkapi.com\/v2\/2.png",
"abv": 4.1,
"ibu": 41.5,
"target_fg": 1010,
"target_og": 1041.7,
"ebc": 15,
"srm": 15,
"ph": 4.4,
"attenuation_level": 76,
"volume": {
"value": 20,
"unit": "liters"
},
"boil_volume": {
"value": 25,
"unit": "liters"
},
"method": {
"mash_temp": [
{
"temp": {
"value": 69,
"unit": "celsius"
},
"duration": null
}
],
"fermentation": {
"temp": {
"value": 18,
"unit": "celsius"
}
},
"twist": null
},
"ingredients": {
"malt": [
{
"name": "Maris Otter Extra Pale",
"amount": {
"value": 3.25,
"unit": "kilograms"
}
},
{
"name": "Caramalt",
"amount": {
"value": 0.2,
"unit": "kilograms"
}
},
{
"name": "Munich",
"amount": {
"value": 0.4,
"unit": "kilograms"
}
}
],
"hops": [
{
"name": "Amarillo",
"amount": {
"value": 13.8,
"unit": "grams"
},
"add": "start",
"attribute": "bitter"
},
{
"name": "Simcoe",
"amount": {
"value": 13.8,
"unit": "grams"
},
"add": "start",
"attribute": "bitter"
},
{
"name": "Amarillo",
"amount": {
"value": 26.3,
"unit": "grams"
},
"add": "end",
"attribute": "flavour"
},
{
"name": "Motueka",
"amount": {
"value": 18.8,
"unit": "grams"
},
"add": "end",
"attribute": "flavour"
}
],
"yeast": "Wyeast 1056 - American Ale\u2122"
},
"food_pairing": [
"Fresh crab with lemon",
"Garlic butter dipping sauce",
"Goats cheese salad",
"Creamy lemon bar doused in powdered sugar"
],
"brewers_tips": "Be careful not to collect too much wort from the mash. Once the sugars are all washed out there are some very unpleasant grainy tasting compounds that can be extracted into the wort.",
"contributed_by": "Sam Mason <samjbmason>"
},
{
"id": 3,
"name": "Berliner Weisse With Yuzu - B-Sides",
"tagline": "Japanese Citrus Berliner Weisse.",
"first_brewed": "11\/2015",
"description": "Japanese citrus fruit intensifies the sour nature of this German classic.",
"image_url": "https:\/\/images.punkapi.com\/v2\/keg.png",
"abv": 4.2,
"ibu": 8,
"target_fg": 1007,
"target_og": 1040,
"ebc": 8,
"srm": 4,
"ph": 3.2,
"attenuation_level": 83,
"volume": {
"value": 20,
"unit": "liters"
},
"boil_volume": {
"value": 25,
"unit": "liters"
},
"method": {
"mash_temp": [
{
"temp": {
"value": 60,
"unit": "celsius"
},
"duration": 10
},
{
"temp": {
"value": 65,
"unit": "celsius"
},
"duration": 30
},
{
"temp": {
"value": 72,
"unit": "celsius"
},
"duration": 10
},
{
"temp": {
"value": 78,
"unit": "celsius"
},
"duration": 5
}
],
"fermentation": {
"temp": {
"value": 21,
"unit": "celsius"
}
},
"twist": "Soured naturally using the kettle souring technique, Yuzu fruit: 50g at middle, Yuzu juice: 200ml at FV"
},
"ingredients": {
"malt": [
{
"name": "Propino Pale Malt",
"amount": {
"value": 1.63,
"unit": "kilograms"
}
},
{
"name": "Wheat Malt",
"amount": {
"value": 1.63,
"unit": "kilograms"
}
},
{
"name": "Propino Pale Malt for kettle 0.03kg souring",
"amount": {
"value": 0.03,
"unit": "kilograms"
}
},
{
"name": "Acidulated Malt for kettle souring",
"amount": {
"value": 0.03,
"unit": "kilograms"
}
}
],
"hops": [
{
"name": "Bramling Cross",
"amount": {
"value": 10,
"unit": "grams"
},
"add": "middle",
"attribute": "bitter"
}
],
"yeast": "Wyeast 1056 - American Ale\u2122"
}
3个回答
2
投票
投票
使用可选绑定来避免这个问题
使用
if let ibu = item?.ibu {
labelAmargor.text = "\(String(describing: ibu))"
}
而不是
labelAmargor.text = "\(String(describing: item!.ibu))"
0
投票
投票
0
投票
投票
环球银行金融电信协会5.7
为了避免或删除“可选”文本，当（打印）函数与可选一起使用时，您必须放置一个“！”在容器的末尾（变量常量等）。 示例：
var name:String? = "jack"
print(name!)
//the "!" ^ is the reason for the optional text not to appear.
最新问题
- 如何让我的代码拒绝无效输入并重复提示？
- 如何将 pdfjs-dist 从 <3.x
- HTML 输入类型数字不适用于 maxlength
- 使用新的结帐块编辑 woocommerce 结帐页面“订单备注”
- SQL 镜像。在 C# 中检测当前服务器
- AvaloniaUI UserControl 属性无法绑定到另一个属性
- 出现该错误的可能原因是什么？
- Sublime Text 2 / Sublime Text 3 在 osx 上恢复未保存的文件
- 在javascript中，我可以将iframe doc分配给文档变量吗？
- 从 localStorage 获取数据时无法更新状态[已关闭]
- 如何忽略特定的div而不在html2pdf中留下空白
- jhipster Angular编译成功，但是AggregateError
- 预检请求成功，但 GET 请求失败，CORS 错误状态代码 200 OK
- 多个 Firebase 项目 |登录
- 这段代码中展开运算符的意义是什么？
- 如何从 Python 中的列表列表中删除超集列表？
- 如何解决“django.db.migrations.exceptions.InconsistentMigrationHistory”错误？ （使用 powershell/VSCode）
- 发生异常时继续 Laravel 作业
- Netsuite Rest Api：销售订单项目履行
- Flutter Web 应用程序在发布模式下不会发生变化
© www.soinside.com 2019 - 2024. All rights reserved.