add +/- button to DecimalButtonInputCell

Author: haojianzong

Sources/ObjectForm/view/DecimalButtonInputCell.swift

@@ -24,6 +24,7 @@ public class DecimalButtonInputCell: FormInputCell {
     }
 
     var numberLocale: Locale?
+    private weak var alertController: UIAlertController?
 
     private lazy var decimalButton: UIButton = {
         let button = UIButton(type: .system)
@@ -109,12 +110,19 @@ public class DecimalButtonInputCell: FormInputCell {
 
     public func showDecimalInput(in viewController: UIViewController) {
         let alertController = UIAlertController(title: "", message: nil, preferredStyle: .alert)
+        self.alertController = alertController
 
-        alertController.addTextField { textField in
+        alertController.addTextField { [weak self] textField in
+            guard let self = self else { return }
             textField.keyboardType = .decimalPad
             if let currentValue = self.outputValue {
                 textField.text = self.numberFormatter.string(from: currentValue)
             }
+            
+            // Add +/- button to keyboard toolbar
+            let minusButton = KeyboardToolbarFactory.factoryKeyboardButton(title: "+/-")
+            minusButton.addTarget(self, action: #selector(self.minusButtonTapped(_:)), for: .touchUpInside)
+            textField.inputAccessoryView = KeyboardToolbarFactory.factoryKeyboardToolbar(leadingButtonList: [UIBarButtonItem(customView: minusButton)])
         }
 
         let cancelAction = UIAlertAction(title: "Cancel", style: .cancel)
@@ -142,4 +150,18 @@ public class DecimalButtonInputCell: FormInputCell {
 
         viewController.present(alertController, animated: true)
     }
+    
+    @objc private func minusButtonTapped(_ button: UIButton) {
+        guard let textField = alertController?.textFields?.first,
+              let text = textField.text else {
+            return
+        }
+        
+        let token = "-"
+        if text.hasPrefix(token) {
+            textField.text = text.replacingOccurrences(of: token, with: "")
+        } else {
+            textField.text = token + text
+        }
+    }
 }

Sources/ObjectForm/view/KeyboardToolbarFactory.swift

@@ -0,0 +1,42 @@
+import UIKit
+
+struct KeyboardToolbarFactory {
+    static func factoryKeyboardButton(title: String) -> UIButton {
+        let button = UIButton(type: .custom)
+        var config = UIButton.Configuration.bordered()
+        config.attributedTitle = AttributedString(title, attributes: {
+            var container = AttributeContainer()
+            container.font = .systemFont(ofSize: 17.0, weight: .medium)
+            return container
+        }())
+        config.baseForegroundColor = .label
+        config.baseBackgroundColor = Self.keyboardToolbarButtonBackground
+        button.layer.shadowOffset = CGSize(width: 0, height: 1)
+        button.layer.shadowRadius = 1.0
+        button.layer.shadowColor = UIColor.black.cgColor
+        button.layer.shadowOpacity = 0.3
+        button.configuration = config
+        return button
+    }
+
+    static var keyboardToolbarButtonBackground: UIColor {
+        return UIColor { (traitCollection: UITraitCollection) -> UIColor in
+            if traitCollection.userInterfaceStyle == .dark {
+                return .systemGray2
+            } else {
+                return .systemBackground
+            }
+        }
+    }
+
+    static func factoryKeyboardToolbar(leadingButtonList: [UIBarButtonItem], trailingButtonList: [UIBarButtonItem]? = nil) -> UIToolbar {
+        let toolbar = UIToolbar(frame: CGRect(x: 0, y: 0, width: 100, height: 50))
+        var buttonItemList = leadingButtonList
+        buttonItemList.append(UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil))
+        if let trailingButtonList {
+            buttonItemList.append(contentsOf: trailingButtonList)
+        }
+        toolbar.setItems(buttonItemList, animated: true)
+        return toolbar
+    }
+}