Example code for article about UndoManager - Recording Commands

RecordingCommands.swift

// 1
func redButtonPressed(_ sender: UIButton) {
    recordColorChangeCommand(newColor: .red)
}

// 2
func recordColorChangeCommand(newColor: UIColor) {
    let currentColor = colorView.backgroundColor
    let command = Command(
        execute: { self.colorView.backgroundColor = newColor },
        reverse: { self.colorView.backgroundColor = currentColor }
    )
    historyService.record(command: command)
    updateActionButtons()
}

// 3
func updateActionButtons() {
    undoButton.isEnabled = historyService.canUndo
    redoButton.isEnabled = historyService.canRedo
}

// 4
func undoButtonPressed(_ sender: UIButton) {
    historyService.undo()
    updateActionButtons()
}