使用将单元格插入表格时，UITableViewCell 不使用自动布局高度 [英] UITableViewCell doesn't use autolayout height when using insert cell into table
问题描述
背景
我使用 purelayout 以编程方式创建我的 UITableViewCells，按照
问题
一切正常，除非我在 tableView 中插入新行.我得到这个效果:
而其他(格式正确)单元格的高度为 25:
虽然您关注的 StackOverflow 答案有很多赞成票，但您似乎选择了一个没有很好解释的要点(可能已经过时)，我认为这可能是导致您出现问题的原因.
您会发现许多评论/帖子/文章指出您应该在 updateConstraints() 中添加约束，但是，
Background
I use purelayout to programmatically create my UITableViewCells, following the instructions here, which basically states that you gotta set the top/bottom constraints on a cell, then use
self.tableView.rowHeight = UITableViewAutomaticDimension;
to get it right:
Problem
Everything works fine, except when I insert a new row into a tableView. I get this effect: https://youtu.be/eTGWsxwDAdk
To explain: as soon as I click on one of the tip cells, the table is supposed to insert a driver tip row. However you'll notice that wen i refresh the section (by clicking on a tip box), all the cells height inexplicably increases, but when i click on tip boxes again, they go back to their normal height this is done with this code
self.tableView.beginUpdates()
self.tableView.reloadSections(IndexSet(integer:1), with: .automatic)
self.tableView.endUpdates()
this is the implementation of the cellfor row
// init table
self.tableView.register(OrderChargeTableViewCell.self,
forCellReuseIdentifier: OrderChargeTableViewCell.regularCellIdentifier)
self.tableView.register(OrderChargeTableViewCell.self,
forCellReuseIdentifier: OrderChargeTableViewCell.boldCellIdentifier)
self.tableView.estimatedRowHeight = 25
self.tableView.rowHeight = UITableViewAutomaticDimension
public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
var cell: OrderChargeTableViewCell?
if (indexPath.row == filteredModel.count-1) {
cell = tableView.dequeueReusableCell(withIdentifier: OrderChargeTableViewCell.boldCellIdentifier,
for: indexPath) as? OrderChargeTableViewCell
} else if (indexPath.row < filteredModel.count) {
cell = tableView.dequeueReusableCell(withIdentifier: OrderChargeTableViewCell.regularCellIdentifier,
for: indexPath) as? OrderChargeTableViewCell
}
// add data to cell labels
return cell!
}
and this is the code for the UITableViewCell itself:
final class OrderChargeTableViewCell: UITableViewCell {
// MARK: - init
static let boldCellIdentifier = "TTOrderDetailBoldTableViewCell"
static let regularCellIdentifier = "TTOrderDetailRegularTableViewCell"
private var didSetupConstraints = false
..
override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
self.keyLabel = TTRLabel()
self.valueLabel = TTRLabel()
if (reuseIdentifier == OrderChargeTableViewCell.regularCellIdentifier) {
self.isCellStyleBold = false
} else if (reuseIdentifier == OrderChargeTableViewCell.boldCellIdentifier) {
self.isCellStyleBold = true
} else {
self.isCellStyleBold = false
assertionFailure( "Attempt to create an OrderCharge cell with the wrong cell identifier: \(String(describing: reuseIdentifier))")
}
super.init(style: style, reuseIdentifier: reuseIdentifier)
contentView.addSubview(keyLabel)
contentView.addSubview(valueLabel)
}
override func updateConstraints()
{
if !didSetupConstraints {
if (isCellStyleBold) {
self.applyBoldFormatting()
} else {
self.applyRegularFormatting()
}
didSetupConstraints = true
}
super.updateConstraints()
}
public func applyBoldFormatting() {
keyLabel.font = .ttrSubTitle
valueLabel.font = .ttrBody
keyLabel.autoPinEdge(.leading, to: .leading, of: contentView, withOffset: 15)
keyLabel.autoAlignAxis(.vertical, toSameAxisOf: contentView)
keyLabel.autoPinEdge(.top, to: .top, of: contentView, withOffset: 8)
keyLabel.autoPinEdge(.bottom, to: .bottom, of: contentView, withOffset: -8)
valueLabel.autoPinEdge(.trailing, to: .trailing, of: contentView, withOffset: -15)
valueLabel.autoAlignAxis(.baseline, toSameAxisOf: keyLabel)
}
public func applyRegularFormatting() {
keyLabel.font = .ttrCaptions
valueLabel.font = TTRFont.Style.standard(.h3).value
keyLabel.autoPinEdge(.leading, to: .leading, of: contentView, withOffset: 15)
keyLabel.autoAlignAxis(.vertical, toSameAxisOf: contentView)
keyLabel.autoPinEdge(.top, to: .top, of: contentView, withOffset: 6)
keyLabel.autoPinEdge(.bottom, to: .bottom, of: contentView, withOffset: -4)
valueLabel.autoPinEdge(.trailing, to: .trailing, of: contentView, withOffset: -15)
valueLabel.autoAlignAxis(.baseline, toSameAxisOf: keyLabel)
}
the driver tip row that gets inserted has the standard 44 pixel height of a cell:
whereas the other (properly formatted) cells have the 25 height:
While the StackOverflow answer you followed has a lot of up-votes, it appears you took one bullet point which was not very well explained (and may be outdated), and I think that may be what's causing your problems.
You'll find many comments / posts / articles stating you should add your constraints in updateConstraints(), however, Apple's docs also state:
Override this method to optimize changes to your constraints.
Note
It is almost always cleaner and easier to update a constraint immediately after the affecting change has occurred. For example, if you want to change a constraint in response to a button tap, make that change directly in the button’s action method.
You should only override this method when changing constraints in place is too slow, or when a view is producing a number of redundant changes.
I think you'll get much better results in what you're attempting if you add your subviews and their constraints when your cell is init'd.
Here is a simple example which has a similar layout to what you've shown. It creates a table with 2 sections - first section has a row with a "show/hide" button. When tapped, the second section will add/remove the "Driver Tip" row.
//
// InsertRemoveViewController.swift
//
// Created by Don Mag on 12/4/18.
//
import UIKit
struct MyRowData {
var title: String = ""
var value: CGFloat = 0.0
}
class OrderChargeTableViewCell: UITableViewCell {
static let boldCellIdentifier: String = "TTOrderDetailBoldTableViewCell"
static let regularCellIdentifier: String = "TTOrderDetailRegularTableViewCell"
var keyLabel: UILabel = {
let v = UILabel()
v.translatesAutoresizingMaskIntoConstraints = false
return v
}()
var valueLabel: UILabel = {
let v = UILabel()
v.translatesAutoresizingMaskIntoConstraints = false
return v
}()
override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
commonInit()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
commonInit()
}
func commonInit() -> Void {
contentView.addSubview(keyLabel)
contentView.addSubview(valueLabel)
let s = type(of: self).boldCellIdentifier
if self.reuseIdentifier == s {
NSLayoutConstraint.activate([
keyLabel.topAnchor.constraint(equalTo: contentView.topAnchor, constant: 8.0),
keyLabel.bottomAnchor.constraint(equalTo: contentView.bottomAnchor, constant: -8.0),
keyLabel.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 15.0),
valueLabel.centerYAnchor.constraint(equalTo: keyLabel.centerYAnchor, constant: 0.0),
valueLabel.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -15.0),
])
keyLabel.font = UIFont.systemFont(ofSize: 15, weight: .bold)
valueLabel.font = UIFont.systemFont(ofSize: 15, weight: .bold)
} else {
NSLayoutConstraint.activate([
keyLabel.topAnchor.constraint(equalTo: contentView.topAnchor, constant: 6.0),
keyLabel.bottomAnchor.constraint(equalTo: contentView.bottomAnchor, constant: -4.0),
keyLabel.leadingAnchor.constraint(equalTo: contentView.leadingAnchor, constant: 15.0),
valueLabel.centerYAnchor.constraint(equalTo: keyLabel.centerYAnchor, constant: 0.0),
valueLabel.trailingAnchor.constraint(equalTo: contentView.trailingAnchor, constant: -15.0),
])
keyLabel.font = UIFont.systemFont(ofSize: 12, weight: .bold)
valueLabel.font = UIFont.systemFont(ofSize: 12, weight: .regular)
}
}
}
class TipCell: UITableViewCell {
var callBack: (() -> ())?
var theButton: UIButton = {
let b = UIButton()
b.translatesAutoresizingMaskIntoConstraints = false
b.setTitle("Tap to Show/Hide Add Tip row", for: .normal)
b.setTitleColor(.blue, for: .normal)
b.backgroundColor = .yellow
return b
}()
override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
commonInit()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
commonInit()
}
func commonInit() -> Void {
contentView.addSubview(theButton)
NSLayoutConstraint.activate([
theButton.topAnchor.constraint(equalTo: contentView.topAnchor, constant: 20.0),
theButton.bottomAnchor.constraint(equalTo: contentView.bottomAnchor, constant: -20.0),
theButton.centerXAnchor.constraint(equalTo: contentView.centerXAnchor, constant: 0.0),
])
theButton.addTarget(self, action: #selector(btnTapped(_:)), for: .touchUpInside)
}
@objc func btnTapped(_ sender: Any?) -> Void {
callBack?()
}
}
class InsertRemoveViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
var myData = [
MyRowData(title: "SUBTOTAL", value: 4),
MyRowData(title: "DELIVERY CHARGE", value: 1.99),
MyRowData(title: "DISCOUNT", value: -1.99),
MyRowData(title: "TOTAL", value: 4),
]
var tableView: UITableView = {
let v = UITableView()
v.translatesAutoresizingMaskIntoConstraints = false
return v
}()
func tipRowShowHide() {
let iPath = IndexPath(row: 3, section: 1)
if myData.count == 4 {
myData.insert(MyRowData(title: "DRIVER TIP", value: 2.0), at: 3)
tableView.insertRows(at: [iPath], with: .automatic)
} else {
myData.remove(at: 3)
tableView.deleteRows(at: [iPath], with: .automatic)
}
}
override func viewDidLoad() {
super.viewDidLoad()
tableView.register(OrderChargeTableViewCell.self,
forCellReuseIdentifier: OrderChargeTableViewCell.regularCellIdentifier)
tableView.register(OrderChargeTableViewCell.self,
forCellReuseIdentifier: OrderChargeTableViewCell.boldCellIdentifier)
tableView.register(TipCell.self, forCellReuseIdentifier: "TipCell")
tableView.delegate = self
tableView.dataSource = self
tableView.rowHeight = UITableViewAutomaticDimension
tableView.estimatedRowHeight = 25
view.backgroundColor = .red
view.addSubview(tableView)
NSLayoutConstraint.activate([
tableView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 200.0),
tableView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor, constant: -20.0),
tableView.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor, constant: 20.0),
tableView.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor, constant: -20.0),
])
}
func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
return " "
}
func numberOfSections(in tableView: UITableView) -> Int {
return 2
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return section == 0 ? 1 : myData.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if indexPath.section == 0 {
let cell = tableView.dequeueReusableCell(withIdentifier: "TipCell", for: indexPath) as! TipCell
cell.callBack = {
self.tipRowShowHide()
}
return cell
}
var cell: OrderChargeTableViewCell?
if indexPath.row == myData.count - 1 {
cell = tableView.dequeueReusableCell(withIdentifier: OrderChargeTableViewCell.boldCellIdentifier,
for: indexPath) as? OrderChargeTableViewCell
} else {
cell = tableView.dequeueReusableCell(withIdentifier: OrderChargeTableViewCell.regularCellIdentifier,
for: indexPath) as? OrderChargeTableViewCell
}
cell?.keyLabel.text = myData[indexPath.row].title
let val = myData[indexPath.row].value
cell?.valueLabel.text = String(format: "%0.02f USD", val)
return cell!
}
}
This is the result:
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