When the number of my cells is relatively small, the table view runs smoothly, but when my number of cells becomes four, it becomes very unsmooth. I need my table view to run very smoothly. And there are some warnings in Xcode. when I add a new cell, it shows
"2019-04-04 14:00:15.939875+0800 ToDoList[12259:2660300] [UIWorkIntervalTiming] workIntervalStart: startTimestamp > targetTimestamp; rolling forward by 11.383334 2019-04-04 14:00:15.943008+0800 ToDoList[12259:2660300] [UIWorkIntervalTiming] workIntervalStart: startTimestamp > targetTimestamp; rolling forward by 5.616667 2019-04-04 14:01:05.601183+0800 ToDoList[12259:2660300] [UIWorkIntervalTiming] workIntervalStart: startTimestamp > targetTimestamp; rolling forward by 2.150000 2019-04-04 14:01:05.602619+0800 ToDoList[12259:2660300] [UIWorkIntervalTiming] workIntervalStart: startTimestamp > targetTimestamp; rolling forward by 43.433334" .
How can I solve this problem?
Nothing I have tried, I don't know where to begin.
and this my UI:
import UIKit
class TableViewController: UITableViewController, UICollectionViewDelegate, UICollectionViewDataSource {
@IBOutlet var emptyItemView: UIView!
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
if toDoItems.count == 1 {
return 1
} else if toDoItems.count == 2 {
return 2
} else if toDoItems.count == 0 {
return 0
} else {
return 3
}
}
func numberOfSections(in collectionView: UICollectionView) -> Int {
return 1
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath) as! imageViewCollectionViewCell
cell.imageView.image = UIImage(data: toDoItems[indexPath.row].imageDataOfItem)
cell.generalLabel.text = toDoItems[indexPath.row].themeOfItem
cell.titleLabel.text = toDoItems[indexPath.row].nameOfItem
cell.subTitleLabel.text = toDoItems[indexPath.row].descriptionOfItem
if toDoItems[indexPath.row].descriptionOfItem == "" {
cell.subTitleLabel.isHidden = true
}
cell.layer.cornerRadius = 10.0
cell.layer.masksToBounds = true
return cell
}
@IBOutlet weak var collectionView: UICollectionView! {
didSet {
collectionView.backgroundColor = .clear
}
}
// 第二组需要自定义cell，这里使用XIB来完成
let nib = UINib(nibName: "BookTableViewCell", bundle: nil)
override func viewDidLoad() {
super.viewDidLoad()
// 必须带上这两句话才有数据
collectionView.delegate = self
collectionView.dataSource = self
navigationItem.leftBarButtonItem = editButtonItem
// 需要用代码注册Nib
self.tableView.register(nib, forCellReuseIdentifier: "TableViewCell")
if let savedToDoLtems = ToDoItem.loadToDoItems() {
toDoItems = savedToDoLtems
} else {
toDoItems = ToDoItem.loadSampleToDoItems()
}
tableView.backgroundView = emptyItemView
tableView.backgroundView?.isHidden = true
}
override func viewWillAppear(_ animated: Bool) {
collectionView.reloadData()
tableView.reloadData()
}
/**
* 这里是第二部分
* 我想要在 CollectionView 下方展示一系列项目，使用 TableViewCell 来显示
* 想要在静态的 cell 里面实现动态的 cell 需要使用 xib 文件
*/
// 以下代理方法必须实现
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if (indexPath.section == 1) {
let cell = tableView.dequeueReusableCell(withIdentifier: "TableViewCell") as? TableViewCell
cell?.classLabel.text = toDoItems[indexPath.row].themeOfItem
cell?.titleLabel.text = toDoItems[indexPath.row].nameOfItem
cell?.subTitle.text = toDoItems[indexPath.row].descriptionOfItem
let image = UIImage(data: toDoItems[indexPath.row].imageDataOfItem)
cell?.backgroundImage.image = image
return cell!
}
return super.tableView(tableView, cellForRowAt: indexPath)
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if section == 1 {
return toDoItems.count //这里返回第二组的行数
}
return super.tableView(tableView, numberOfRowsInSection: section)
}
override func numberOfSections(in tableView: UITableView) -> Int {
if toDoItems.count > 0 {
tableView.backgroundView?.isHidden = true
tableView.separatorStyle = .singleLine
tableView.isScrollEnabled = true
} else {
tableView.backgroundView?.isHidden = false
tableView.separatorStyle = .none
tableView.isScrollEnabled = false
}
return 2
}
override func tableView(_ tableView: UITableView, indentationLevelForRowAt indexPath: IndexPath) -> Int {
if indexPath.section == 1 {
return super.tableView(tableView, indentationLevelForRowAt: IndexPath(row: 0, section: 1))
}
return super.tableView(tableView, indentationLevelForRowAt: indexPath)
}
override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
if indexPath.section == 1 {
return 120
}
return super.tableView(tableView, heightForRowAt: indexPath)
}
// Override to support conditional editing of the table view.
override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
if indexPath.section == 1 {
return true
} else {
return false
}
}
// Override to support editing the table view.
override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
if indexPath.section == 1 {
if editingStyle == .delete {
toDoItems.remove(at: indexPath.row)
tableView.deleteRows(at: [indexPath], with: .fade)
self.collectionView.reloadData()
ToDoItem.saveToDoItems(toDoItems)
}
}
}
// --- 这个功能为了实现点击每一个cell实现跳转 ---
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
if indexPath.section == 1 {
let todoitem = toDoItems[indexPath.row]
self.performSegue(withIdentifier: "EachItem", sender: todoitem)
}
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
// Get the new view controller using segue.destination.
// Pass the selected object to the new view controller.
if segue.identifier == "EachItem" {
let todoTableViewController = segue.destination as! ToDoTableViewController
let indexPath = tableView.indexPathForSelectedRow!
let selectedToDoItem = toDoItems[indexPath.row]
todoTableViewController.todoItem = selectedToDoItem
todoTableViewController.todos = selectedToDoItem.todos
todoTableViewController.positionOfToDoItem = indexPath.row
}
if segue.identifier == "CollectionSegue" {
if let indexPaths = collectionView.indexPathsForSelectedItems {
let destinationController = segue.destination as! ToDoTableViewController
destinationController.todoItem = toDoItems[indexPaths[0].row]
destinationController.todos = toDoItems[indexPaths[0].row].todos
destinationController.positionOfToDoItem = indexPaths[0].row
collectionView.deselectItem(at: indexPaths[0], animated: false)
}
}
}
@IBAction func unwindToToDoItem(segue: UIStoryboardSegue) {
if segue.identifier == "SaveNewItemSegue" {
let sourceViewController = segue.source as! EditItemTableViewController
if let item = sourceViewController.toDoItem {
let newIndexPath = IndexPath(row: toDoItems.count, section: 1)
toDoItems.append(item)
tableView.insertRows(at: [newIndexPath], with: .automatic)
ToDoItem.saveToDoItems(toDoItems)
}
}
}
}
