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[英]How do I access a variable in one view controller from another view controller?
[英]How do I get a value from a variable in another View Controller
我试图从 ViewController 的 PrefsViewController 中的 4 个不同变量中获取值,但是当 PrefsViewController 被解除时,这些值会重置。
class ViewController: NSViewController, NSWindowDelegate {
var triesEnabled = false
var minNumber = 0
var maxNumber = 20
var maxTries = 3
@objc func applyPrefs() {
let mainSB = NSStoryboard(name: "Main", bundle: nil)
let prefsVC: PrefsViewController = mainSB.instantiateController(withIdentifier: "prefsViewController") as! PrefsViewController
minNumber = prefsVC.prefsMinNum
maxNumber = prefsVC.prefsMaxNum
triesEnabled = prefsVC.prefsTriesEnabled
maxTries = prefsVC.prefsMaxTries
print("\(minNumber) \(maxNumber) \(triesEnabled) \(maxTries)") // here I can see that it has been reset to the default values
resetGame(minRange: minNumber, maxRange: maxNumber, isTriesEnabled: triesEnabled, triesLimit: maxTries)
}
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(applyPrefs), name: Notification.Name("notifyApplyPrefs"), object: nil )
resetGame(minRange: minNumber, maxRange: maxNumber, isTriesEnabled: triesEnabled, triesLimit: maxTries)
}
}
class PrefsViewController: NSViewController {
var triesOn = false
var prefsMinNum: Int = 0
var prefsMaxNum: Int = 20
var prefsTriesEnabled: Bool = false
var prefsMaxTries: Int = 3
@IBAction func closeButton(_ sender: Any) {
if (!minNumTextField.stringValue.isInt || !maxNumTextField.stringValue.isInt || !triesTextField.stringValue.isInt) {
let alert = NSAlert()
alert.messageText = "Error"
alert.informativeText = "You can only enter (whole) numbers in the text fields."
alert.alertStyle = .warning
alert.addButton(withTitle: "OK")
alert.runModal()
return
}
prefsMinNum = Int(minNumTextField.intValue)
prefsMaxNum = Int(maxNumTextField.intValue)
prefsTriesEnabled = triesOn
prefsMaxTries = Int(minNumTextField.intValue)
print("minNumTextField: \(prefsMinNum) maxNumTextField: \(prefsMaxNum) triesCheckBox: \(prefsTriesEnabled) triesTextField: \(prefsMaxTries)")
NotificationCenter.default.post(name: Notification.Name("notifyApplyPrefs"), object: nil)
self.dismiss(self)
}
}
首选项视图显示为工作表(我不知道这是否重要)
当您使用instantiateController
您正在创建一个新的、以前从未使用过的控制器实例。 如果要使用通知传输数据,请在调用post
时将self
作为对象发送,然后使用它来获取变量。
您还需要更改applyPrefs
以便它采用 Notification 参数,以便您可以使用通知对象。
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