在领域Swift中检索存储的数据 [英] Retriving stored data in realm Swift
问题描述
我有一个待办事项应用程序,正在使用领域来存储数据.我已经写了用于写入数据库并检索的数据库代码.之前,我还以单个页面代码的形式处理了这个特定项目,但现在我想使用MVC方法进行改进.这是我的密码.
I have a todo application which I am using realm to store data. i have writen the database codes for writing to the database and retrive. I have also worked on this particular project before in as a single page code but now I want to improve it by using the MVC approach. this is my codes.
//MARK:- Create Category
func createCategory(name: String, color: String, isCompleted: Bool) -> Void {
category.name = name
category.color = color
category.isCompleted = false
DBManager.instance.addData(object: category)
}
//MARK:- Read Category
func readCategory(completion: @escaping CompletionHandler) -> Void {
DBManager.instance.getDataFromDB().forEach({ (category) in
let category = CategoryModel()
Data.categoryModels.append(category)
})
}
数据库模型
private init() {
database = try! Realm()
}
func getDataFromDB() -> Results<CategoryModel> {
let categoryArray: Results<CategoryModel> = database.objects(CategoryModel.self)
return categoryArray
}
func addData(object: CategoryModel) {
try! database.write {
database.add(object, update: true)
print("Added new object")
}
}
TodoList单元格
func setup(categoryModel: CategoryModel) -> Void {
categoryNameLabel.text = categoryModel.name
}
Todo tableviewcontroller func tableView(_ tableView:UITableView,cellForRowAt indexPath:IndexPath)-> UITableViewCell {
Todo tableviewcontroller func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: Constants.CATEGORY_CELL) as! CategoryCell
cell.setup(categoryModel: Data.categoryModels[indexPath.row])
return cell
}
我能够添加到数据库,就像添加到数据库后可以打印一样,但是我对如何检索添加的数据感到困惑.
I am able to add to the database as I can print after adding to the database but I am confused as to how to retrieve the added data.
没有MVC categorylist.swift
let realm = try! Realm()
var categoryArray : Results<Category>?
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of rows
//nil coalising operator
return Data.categoryModels.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
//tapping into the super class
let cell = super.tableView(tableView, cellForRowAt: indexPath)
if let category = categoryArray?[indexPath.row] {
cell.textLabel?.text = "#\(category.name)"
guard let categoryColor = UIColor(hexString: category.color) else {fatalError()}
cell.backgroundColor = categoryColor
cell.textLabel?.textColor = ContrastColorOf(categoryColor, returnFlat: true)
}
return cell
}
推荐答案
因为您在此处创建了单例
Since you create a singleton here
DBManager.instance
您可以在numberOfRowsInSection
return DBManager.instance.getDataFromDB().count
和cellForRowAt
let item = DBManager.instance.getDataFromDB()[indexPath.row]
但这会在每次执行时继续读取数据,因此最好只删除
but this will keep reading the data every execute , so it's better to remove only
let realm = try! Realm()
当重构为 MVC 并在viewDidLoad
categoryArray = DBManager.instance.getDataFromDB()
并保留其他部分不变,请注意:在这里,我假设 Category = CategoryModel
and leave the other parts unchanged , note: here i assume that Category = CategoryModel
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