ios - 如何: check for nil on every value before presentation of ViewController

Question

下面我有一个tableView委托(delegate)方法

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    tableView.deselectRow(at: indexPath, animated: true)

    lessonView?.lessonName = (capturedLessons?[indexPath.row].name)!

    lessonView?.instructorGradedTracked = capturedLessons![indexPath.row].instructorGraded!

    lessonView?.expectedCompletionTimeTracked = capturedLessons![indexPath.row].expectedCompletionTime!

    self.present(self.lessonView!, animated: true, completion: nil)

}

lessonName: String
instructorGraded: Bool
expectedCompletionTime: Int

我在设置对 bool 和 int 值的 nil 检查时遇到问题。实现此错误处理的最佳做法是什么？

Answer 1

你可以试试

guard let item = capturedLessons?[indexPath.row] ,let name = item.name,  let graded = item.instructorGraded , let completionTime = item.expectedCompletionTime else { return }
lessonView?.lessonName = name
lessonView?.instructorGradedTracked = graded
lessonView?.expectedCompletionTimeTracked = completionTime
self.present(self.lessonView!, animated: true, completion: nil)