[英]UIButton inside UISegmentedControl action
我正在继续我的计算程序,以提高我在Swift代码中的技能。 现在,我遇到一个问题:我希望UISegmentedControl选择我的操作的运算符(+,-ecc ..),并且当选择一个操作符时,UIButton函数会根据UISegmentedControl的决定来计算值。
这是代码,但不起作用。
谢谢,Matteo
import UIKit
class ViewController: UIViewController {
@IBOutlet weak var firstNumber: UITextField!
@IBOutlet weak var secondNumber: UITextField!
@IBOutlet weak var resultButton: UIButton!
@IBOutlet weak var resultNumber: UILabel!
@IBOutlet weak var operatorSelector: UISegmentedControl!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
@IBAction func operatorSelectorChanged(_ sender: UISegmentedControl) {
switch operatorSelector.selectedSegmentIndex {
case 0:
@IBAction func resultFunction(_ sender: AnyObject) {
if let firstNumberConv :Int = Int(firstNumber.text!), let secondNumberConv :Int = Int(secondNumber.text!) {
let result = firstNumberConv + secondNumberConv
resultNumber.text = "\(result)"
} else { resultNumber.text = "Inserire solo valori numerici"}
}
case 1:
@IBAction func resultFunction(_ sender: AnyObject) {
if let firstNumberConv :Int = Int(firstNumber.text!), let secondNumberConv :Int = Int(secondNumber.text!) {
let result = firstNumberConv - secondNumberConv
resultNumber.text = "\(result)"
} else { resultNumber.text = "Inserire solo valori numerici"}
}
default:
break;
}
}
}
尝试在开关盒内使用@IBAction func ...
删除行。
我认为您的@IBAction func operatorSelectorChanged
应该看起来像这样:
@IBAction func operatorSelectorChanged(_ sender: UISegmentedControl) {
switch operatorSelector.selectedSegmentIndex {
case 0:
if let firstNumberConv = Int(firstNumber.text!), let secondNumberConv = Int(secondNumber.text!) {
let result = firstNumberConv + secondNumberConv
resultNumber.text = "\(result)"
} else { resultNumber.text = "Inserire solo valori numerici"}
case 1:
if let firstNumberConv = Int(firstNumber.text!), let secondNumberConv = Int(secondNumber.text!) {
let result = firstNumberConv - secondNumberConv
resultNumber.text = "\(result)"
} else { resultNumber.text = "Inserire solo valori numerici"}
default:
break;
}
}
您的问题的可能解决方案是定义一个IBAction来计算两个数字相加/相减的结果
@IBAction func calculate(_ sender: AnyObject) {
if let a = Int(firstNumber.text!), let b = IntsecondNumber.text!) {
switch operatorSelector.selectedSegmentIndex {
case 0:
resultNumber.text = "\(a+b)"
case 1:
resultNumber.text = "\(a-b)"
default:
print("❗️unknown operator selected")
}
}
}
然后,您可以将此操作绑定到从用户界面发送的事件:例如,文本字段(firstNumber和secondNumber)的Editing Changed
事件和分段控件的Value Changed
(operatorSelector)
我创建了一个示例项目来说明这一点: https : //github.com/dev1an/calculator
用代码写下IBAction(就像我上面写的calculate动作一样)。 转到情节提要,然后打开辅助编辑器( Alt Cmd Enter )。 在界面构建器中选择一个UI元素(如文本字段)。 打开“连接”检查器( Alt Cmd 6 ),然后从已发送事件(例如,“ Edited Changed”)旁边的圆圈拖动到IBAction代码。
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