changeDeleteMode.swift

@IBAction func changeDeleteMode(_ sender: Any) {
        
        // 遍歷 listTableView 將所有被選取的 cell 取消選取
        for row in 0...myTask.count - 1{
            listTableView.cellForRow(at: [0,row])?.isSelected = false
        }
        
        // 判斷左上角的 BarButtonItem.title，進行相對的模式切換
        if self.navigationItem.leftBarButtonItem?.title == "Single" {
            self.navigationItem.leftBarButtonItem?.title = "Multiple"
            deleteMode = UITableViewCellEditingStyle.insert
        } else {
            self.navigationItem.leftBarButtonItem?.title = "Single"
            deleteMode = UITableViewCellEditingStyle.delete
        }
        
        // 如果正在修改的話，則回復到沒有修改的狀態
        if listTableView.isEditing {
            setEditing(false, animated: true)
            listTableView.isEditing = false
        }
        
    }