ios - 从 JSON 加载信息
<p><p>我的 JSON 文件中有 3 行(问题)。当应用程序启动时，我想从 JSON 加载信息。在 <code>title</code> 我想从 <code>question.number</code> 加载信息，在 <code>textLabel.text</code> 我想从 <code>question.text< 加载信息</code>，在 <code>showAnswerLabel.text</code> 我想从 <code>question.answer</code> 加载信息。当我从 <code>question.answer</code> 中写入 <code>textField</code> 正确答案并按下键盘上的完成按钮时，我想看到 <code>print("right")</code>在控制台和我的设备中，我想查看下一个问题。但我有一个问题。当应用程序启动时，我从 JSON 加载第一行 (<code>{"number": "1", "text": "1", "answer": "1"},</code>)。在我的 <code>showAnswerLabel.text</code> answer = <code>1</code> 中。但是当我在 <code>textField</code> 中编写 <code>1</code> 并按下完成按钮时，我没有在控制台中得到 <code>print("right")</code> 。但是如果我从第二行写 answer = <code>2</code> (<code>{"number": "2", "text": "2", "answer": "2"},</code>) 从 <code>textField</code> 中的 JSON 并按完成按钮，我在控制台中得到 <code>print("right")</code>。但正确答案应该是 <code>showAnswerLabel.text</code> 中的数字，即 <code>1</code>。如何解决？ </p>
<p>我的新代码:</p>
<pre><code>{
"questions" : [{"number": "1", "text": "1", "answer": "1"},
{"number": "2", "text": "2", "answer": "2"},
{"number": "3", "text": "3", "answer": "3"}]
}
struct Root : Decodable {
let questions :
}
struct Question : Decodable {
let number, text, answer : String
}
class ViewController: UIViewController, UITextFieldDelegate {
var counter = 0
var questions = ()
@IBOutlet var textLabel: UILabel!
@IBOutlet var showAnswerLabel: UILabel!
@IBOutlet weak var textField: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
let url = Bundle.main.url(forResource: "0", withExtension: "json")!
let data = try! Data(contentsOf: url)
let result = try! JSONDecoder().decode(Root.self, from: data)
self.questions = result.questions
textField.delegate = self
textField.returnKeyType = .done
_ = textFieldShouldReturn(textField)
}
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
textField.resignFirstResponder()
let question = questions
title = question.number
textLabel.text = question.text
showAnswerLabel.text = question.answer
counter = (counter + 1) % questions.count
if textField.text == question.answer {
print("right")
}
return true
}
</code></pre></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>从 <code>textFieldShouldReturn</code> 中提取 UI 更新并绑定(bind)到 <code>counter</code> 的更改的可能修复:</p>
<pre><code>class ViewController: UIViewController, UITextFieldDelegate
{
var questions = ()
@IBOutlet var textLabel: UILabel!
@IBOutlet var showAnswerLabel: UILabel!
@IBOutlet weak var textField: UITextField!
var counter: Int = -1 {
didSet {
guard counter >= 0, counter < questions.count else { fatalError() }
let question = questions
updateUI(with: question)
}
}
override func viewDidLoad()
{
super.viewDidLoad()
let url = Bundle.main.url(forResource: "0", withExtension: "json")!
let data = try! Data(contentsOf: url)
let result = try! JSONDecoder().decode(Root.self, from: data)
self.questions = result.questions
textField.delegate = self
textField.returnKeyType = .done
counter = 0 // will trigger `updateUI(with: questions)`
}
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
textField.resignFirstResponder()
let question = questions
if textField.text == question.answer {
print("right")
// increment counter only answer is right
// will trigger an UI update
counter = (counter + 1) % questions.count
}
return true
}
func updateUI(with question: Question) {
title = question.number
textLabel.text = question.text
showAnswerLabel.text = question.answer
}
}
</code></pre>
<p>我不会完全这样做，但你明白了。</p></p>
<p style="font-size: 20px;">关于ios - 从 JSON 加载信息，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/48183879/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/48183879/
</a>
</p>
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