更改包装在UITableViewCell中的视图的高度约束 [英] Change Height Constraint for View wrapped in UITableViewCell
问题描述
我有一个UITableView，其中包含一个包含视图的自定义单元格.
I have a UITableView with a custom cell that contains a view.
显示视图后，我想更改嵌套视图的高度.
After the view is displayed, I want to change the hight of the nested view.
我正在使用SnapKit框架的updateConstraints函数.
Im using the updateConstraints function of the SnapKit framework.
但是，我得到了一个错误，即更新的约束与显然来自初始设置高度的UIView-Encapsulated-Layout-Height冲突.
However, I get the error, that the updated constraint conflicts with the UIView-Encapsulated-Layout-Height that apparently comes from the initial set height.
"<SnapKit.LayoutConstraint:0x2807666a0@ViewController.swift#89 SnapKitTest.NestedView:0x102005ef0.height == 100.0>",
"<SnapKit.LayoutConstraint:0x280766880@ViewController.swift#70 SnapKitTest.NestedView:0x102005ef0.top == SnapKitTest.TestCell:0x10280e200.top>",
"<SnapKit.LayoutConstraint:0x280766940@ViewController.swift#70 SnapKitTest.NestedView:0x102005ef0.bottom == SnapKitTest.TestCell:0x10280e200.bottom>",
"<NSLayoutConstraint:0x280058a50 'UIView-Encapsulated-Layout-Height' SnapKitTest.TestCell:0x10280e200.height == 20 (active)>"
)
Will attempt to recover by breaking constraint
<SnapKit.LayoutConstraint:0x2807666a0@ViewController.swift#89 SnapKitTest.NestedView:0x102005ef0.height == 100.0>
下面是一些运行示例应用程序的源代码:
Below is some source code to run a sample app:
import UIKit
import SnapKit
class ViewController: UIViewController {
let tableView = UITableView.init(frame: .zero)
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(tableView)
tableView.snp.makeConstraints { make in
make.edges.equalTo(self.view)
}
tableView.register(UITableViewCell.self, forCellReuseIdentifier: "X")
tableView.rowHeight = UITableView.automaticDimension
tableView.estimatedRowHeight = 100
tableView.delegate = self
tableView.dataSource = self
}
override func viewDidAppear(_ animated: Bool) {
if let c = tableView.cellForRow(at: IndexPath(row: 5, section: 0)) as? TestCell {
c.nestedView.snp.updateConstraints { make in
make.height.equalTo(100)
}
} else {
print("didnt geht cell")
}
}
}
extension ViewController: UITableViewDelegate, UITableViewDataSource {
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if indexPath.row == 5 {
let c = TestCell.init(style: .default, reuseIdentifier: nil)
return c
}
let c = tableView.dequeueReusableCell(withIdentifier: "X")
c?.backgroundColor = .orange
return c!
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 10
}
}
class TestCell: UITableViewCell {
let nestedView = NestedView()
override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
addSubview(nestedView)
nestedView.snp.makeConstraints { make in
make.edges.equalTo(self)
}
backgroundColor = .blue
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
class NestedView: UIView {
init() {
super.init(frame: .zero)
backgroundColor = .yellow
snp.makeConstraints { make in
make.height.equalTo(20)
}
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
推荐答案
您不想这样做.据我所知，那是行不通的.您需要在单元格的init中设置约束.或在您的cellForRow函数中.
You don't wanna do that. And that won't work, as far as I know. You need to setup your constraints, either in your cell's init. Or in your cellForRow function.
因此，在下面的代码中，我修改了您的代码，并在TestCell单元格内添加了NestedView的属性(高度约束).然后在cellForRow中更新该高度.
So in my codes below, I modified yours, and I add a property (height constraint) of your NestedView inside your TestCell cell. And I update that height inside the cellForRow.
如果要切换单元格的高度，当然可以用相同的方法进行操作，只需要重新加载tableView的行/节或整个数据即可.
if you want to toggle a cell height, of course you do it the same way, you just need to reload the rows/sections or whole data of your tableView.
ViewController.swift
import UIKit
import SnapKit
class ViewController: UIViewController {
let tableView = UITableView.init(frame: .zero)
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(tableView)
tableView.snp.makeConstraints { make in
make.edges.equalTo(self.view)
}
tableView.register(UITableViewCell.self, forCellReuseIdentifier: "X")
tableView.rowHeight = UITableView.automaticDimension
tableView.estimatedRowHeight = 100
tableView.delegate = self
tableView.dataSource = self
}
}
extension ViewController: UITableViewDelegate, UITableViewDataSource {
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if indexPath.row == 5 {
let c = TestCell.init(style: .default, reuseIdentifier: nil)
c.constraint_HeightOfNestedView?.update(offset: 100.0)
return c
}
let c = tableView.dequeueReusableCell(withIdentifier: "X")
c?.backgroundColor = .orange
return c!
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 10
}
}
TestCell.swift
import SnapKit
class TestCell: UITableViewCell {
var constraint_HeightOfNestedView: Constraint?
let nestedView = NestedView()
override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
addSubview(nestedView)
nestedView.snp.makeConstraints { make in
make.edges.equalTo(self)
self.constraint_HeightOfNestedView = make.height.equalTo(20.0).priority(999).constraint
}
backgroundColor = .blue
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
NestedView.swift
import UIKit
class NestedView: UIView {
override init(frame: CGRect) {
super.init(frame: frame)
backgroundColor = .yellow
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
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