- html - 出于某种原因,IE8 对我的 Sass 文件中继承的 html5 CSS 不友好?
- JMeter 在响应断言中使用 span 标签的问题
- html - 在 :hover and :active? 上具有不同效果的 CSS 动画
- html - 相对于居中的 html 内容固定的 CSS 重复背景?
我正在尝试将 UIStackView 添加到我的窗口,但它没有显示。如下所示,我已经成功添加了 UINavigationBar。我还尝试添加各种其他控件,但实际上只出现了另一个 UIView。我已经附上了我的 ViewController 类:
class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
var pickerData: [String] = [String]()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
pickerData = ["Select a segment..."]
let guide = view.safeAreaLayoutGuide
let safeHeight = guide.layoutFrame.size.height
let safeWidth = guide.layoutFrame.size.width
let navBar = UINavigationBar(frame: CGRect(x: 0, y: safeHeight, width: 20, height: 44))
self.view.addSubview(navBar)
navBar.leadingAnchor.constraint(equalTo: self.view.leadingAnchor, constant: 0).isActive = true
navBar.trailingAnchor.constraint(equalTo: self.view.trailingAnchor, constant: 0).isActive = true
navBar.topAnchor.constraint(equalTo: guide.topAnchor, constant: 0).isActive = true
navBar.translatesAutoresizingMaskIntoConstraints = false
let navItem = UINavigationItem(title: "Add Binge Segment")
let cancelItem = UIBarButtonItem(barButtonSystemItem: UIBarButtonItem.SystemItem.cancel, target: nil, action: #selector(cancel))
navItem.leftBarButtonItem = cancelItem
navBar.setItems([navItem], animated: false)
var items:[UIView] = [UIView]()
let picker = UIPickerView(frame: CGRect(x: safeWidth, y: navBar.frame.height + 50, width: 320, height: 230))
picker.showsSelectionIndicator = true
picker.delegate = self
picker.dataSource = self
items.append(picker)
let stackView = UIStackView()
stackView.axis = .vertical
stackView.distribution = .fillProportionally
stackView.alignment = .fill
stackView.spacing = 10
stackView.backgroundColor = .green
stackView.translatesAutoresizingMaskIntoConstraints = false
self.view.addSubview(stackView)
stackView.topAnchor.constraint(equalTo: navBar.bottomAnchor, constant: 50).isActive = true
stackView.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 50).isActive = true
stackView.trailingAnchor.constraint(equalTo: guide.trailingAnchor, constant: 0).isActive = true
stackView.leadingAnchor.constraint(equalTo: guide.leadingAnchor, constant: 0).isActive = true
stackView.addArrangedSubview(picker)
}
@objc func cancel() {
print("Clicked")
}
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 0
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return pickerData.count
}
}
关于为什么没有显示有什么想法吗?我看到的大多数答案都建议添加约束,但我已经有了它们
编辑:新 View Controller :
class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
var pickerData: [String] = [String]()
var guide: UILayoutGuide = UILayoutGuide()
var safeHeight: CGFloat = 0.0
var safeWidth: CGFloat = 0.0
var navBar: UINavigationBar = UINavigationBar()
var stackView: UIStackView = UIStackView()
var picker: UIPickerView = UIPickerView()
var currentSelection: String = ""
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
pickerData = ["Select a segment..."]
guide = view.safeAreaLayoutGuide
safeHeight = guide.layoutFrame.size.height
safeWidth = guide.layoutFrame.size.width
navBar = UINavigationBar(frame: CGRect(x: 0, y: safeHeight, width: 20, height: 44))
self.view.addSubview(navBar)
picker = UIPickerView(frame: CGRect(x: safeWidth, y: navBar.frame.height + 50, width: 320, height: 230))
self.view.addSubview(picker)
stackView.axis = .vertical
stackView.distribution = .fillProportionally
stackView.alignment = .fill
stackView.spacing = 10
self.view.addSubview(stackView)
}
override func viewWillLayoutSubviews() {
navBar.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 0)
navBar.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: 0)
navBar.topAnchor.constraint(equalToSystemSpacingBelow: guide.topAnchor, multiplier: 0)
navBar.translatesAutoresizingMaskIntoConstraints = false
let navItem = UINavigationItem(title: "Add Binge Segment")
let cancelItem = UIBarButtonItem(barButtonSystemItem: UIBarButtonItem.SystemItem.cancel, target: nil, action: #selector(cancel))
navItem.leftBarButtonItem = cancelItem
navBar.setItems([navItem], animated: false)
var items:[UIView] = [UIView]()
picker.showsSelectionIndicator = true
picker.delegate = self
picker.dataSource = self
items.append(picker)
stackView.translatesAutoresizingMaskIntoConstraints = false
stackView.topAnchor.constraint(equalTo: navBar.bottomAnchor, constant: 50).isActive = true
stackView.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 50).isActive = true
stackView.trailingAnchor.constraint(equalTo: guide.trailingAnchor, constant: 0).isActive = true
stackView.leadingAnchor.constraint(equalTo: guide.leadingAnchor, constant: 0).isActive = true
stackView.addArrangedSubview(picker)
}
@objc func cancel() {
print("Clicked")
}
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 0
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return pickerData.count
}
// The data to return fopr the row and component (column) that's being passed in
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return pickerData[row]
}
// Capture the picker view selection
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
// This method is triggered whenever the user makes a change to the picker selection.
// The parameter named row and component represents what was selected.
currentSelection = pickerData[row]
}
最佳答案
首先,使用约束时不需要指定框架。让自动布局引擎为您完成工作。
其次,约束都可以在 viewDidLoad()
中设置——您不需要在 viewWillLayoutSubviews()
中设置任何内容。
第三,不太清楚您希望选择器 View 在哪里显示,或者为什么将其放在堆栈 View 中?我假设您希望选择器从导航栏底部下方 50 点处开始,并且您将向堆栈 View 添加其他元素?
所以,有一些提示:
调试 View 层次结构
帮助找出错误/缺失的约束这是我得到的:
对代码进行这些修改:
class BenDentViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {
var pickerData: [String] = [String]()
// instantiate navBar, stackView and picker
var navBar: UINavigationBar = UINavigationBar()
var stackView: UIStackView = UIStackView()
var picker: UIPickerView = UIPickerView()
var currentSelection: String = ""
override func viewDidLoad() {
super.viewDidLoad()
// sample picker data
pickerData = [
"Select a segment...",
"Segment 1",
"Segment 2",
"Segment 3",
"Segment 4",
]
// set navBar properties
let navItem = UINavigationItem(title: "Add Binge Segment")
let cancelItem = UIBarButtonItem(barButtonSystemItem: UIBarButtonItem.SystemItem.cancel, target: self, action: #selector(cancel))
navItem.leftBarButtonItem = cancelItem
navBar.setItems([navItem], animated: false)
// set picker properties
picker.showsSelectionIndicator = true
picker.delegate = self
picker.dataSource = self
// give it a background color so we can see its frame
picker.backgroundColor = .yellow
// set stackView properties
stackView.axis = .vertical
stackView.distribution = .fill
stackView.alignment = .fill
stackView.spacing = 10
// add the picker to the stack view
stackView.addArrangedSubview(picker)
// add elements to self.view
self.view.addSubview(navBar)
self.view.addSubview(stackView)
// we're using auto-layout constraints
[navBar, stackView, picker].forEach {
$0.translatesAutoresizingMaskIntoConstraints = false
}
let guide = view.safeAreaLayoutGuide
NSLayoutConstraint.activate([
// constrain navBar to top, leading, trailing and height of 44
navBar.topAnchor.constraint(equalToSystemSpacingBelow: guide.topAnchor, multiplier: 0),
navBar.leadingAnchor.constraint(equalTo: guide.leadingAnchor, constant: 0),
navBar.trailingAnchor.constraint(equalTo: guide.trailingAnchor, constant: 0),
navBar.heightAnchor.constraint(equalToConstant: 44.0),
// constrain stackView leading and trailing
stackView.trailingAnchor.constraint(equalTo: guide.trailingAnchor, constant: 0),
stackView.leadingAnchor.constraint(equalTo: guide.leadingAnchor, constant: 0),
// constrain stackView top: 50-pts from bottom of navBar
stackView.topAnchor.constraint(equalTo: navBar.bottomAnchor, constant: 50),
// not needed, depending on desired layout
//stackView.bottomAnchor.constraint(equalTo: guide.bottomAnchor, constant: -50),
])
}
@objc func cancel() {
print("Cancel Clicked")
}
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 1
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return pickerData.count
}
// The data to return fopr the row and component (column) that's being passed in
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return pickerData[row]
}
// Capture the picker view selection
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
// This method is triggered whenever the user makes a change to the picker selection.
// The parameter named row and component represents what was selected.
currentSelection = pickerData[row]
print("Selected row: \(row) value: \(pickerData[row])")
}
}
关于swift - UIStackView 未显示,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/58053655/
有没有办法在 .swift 文件(编译成 .swift 模块)中声明函数,如下所示: 你好.swift func hello_world() { println("hello world")
我正在尝试使用 xmpp_messenger_ios 和 XMPPFramework 在 iOS 上执行 MUC 这是加入房间的代码。 func createOrJoinRoomOnXMPP()
我想在我的应用程序上创建一个 3D Touch 快捷方式,我已经完成了有关快捷方式本身的所有操作,它显示正确,带有文本和图标。 当我运行这个快捷方式时,我的应用程序崩溃了,因为 AppDelegate
我的代码如下: let assetTag = Expression("asset_tag") let query2 = mdm.select(mdm[assetTag],os, mac, lastRe
我的 swift 代码如下所示 Family.arrayTuple:[(String,String)]? = [] Family.arrayTupleStorage:String? Family.ar
这是我的 JSON,当我读取 ord 和 uniq 数据时出现错误 let response2 : [String: Any] = ["Response":["status":"SUCCESS","
我想将 swift 扩展文件移动到 swift 包中。但是,将文件移动到 swift 包后,我遇到了这种错误: "Type 'NSAttributedString' has no member 'ma
使用CocoaPods,我们可以设置以下配置: pod 'SourceModel', :configurations => ['Debug'] 有什么方法可以用 Swift Package Manag
我正在 Xcode 中开发一个 swift 项目。我将其称为主要项目。我大部分都在工作。我在日期选择器、日期范围和日期数学方面遇到了麻烦,因此我开始了另一个名为 StarEndDate 的项目,其中只
这是 ObjectiveC 代码: CCSprite *progress = [CCSprite spriteWithImageNamed:@"progress.png"]; mProgressBar
我正在创建一个命令行工具,在 Xcode 中使用 Swift。我想使用一个类似于 grunt 的配置文件确实如此,但我希望它是像 Swift 包管理器的 package.swift 文件那样的快速代码
我假设这意味着使用系统上安装的任何 swift 运行脚本:#!/usr/bin/swift 如何指定脚本适用的解释器版本? 最佳答案 Cato可用于此: #!/usr/bin/env cato 1.2
代码说完全没问题,没有错误,但是当我去运行模拟器的时候,会出现这样的字样: (Swift.LazyMapCollection (_base:[ ] 我正在尝试创建一个显示报价的报价应用。 这是导入
是否可以在运行 Swift(例如 Perfect、Vapor、Kitura 等)的服务器上使用 RealmSwift 并使用它来存储数据? (我正在考虑尝试将其作为另一种解决方案的替代方案,例如 no
我刚开始学习编程,正在尝试完成 Swift 编程书中的实验。 它要求““编写一个函数,通过比较两个 Rank 值的原始值来比较它们。” enum Rank: Int { case Ace = 1 ca
在您将此问题标记为重复之前,我检查了 this question 它对我不起作用。 如何修复这个错误: error: SWIFT_VERSION '5.0' is unsupported, suppo
从 Xcode 9.3 开始,我在我的模型中使用“Swift.ImplicitlyUnwrappedOptional.some”包裹了我的字符串变量 我不知道这是怎么发生的,但它毁了我的应用程序! 我
这个问题在这里已经有了答案: How to include .swift file from other .swift file in an immediate mode? (2 个答案) 关闭 6
我正在使用 Swift Package Manager 创建一个应用程序,我需要知道构建项目的配置,即 Debug 或 Release。我试图避免使用 .xcodeproj 文件。请有人让我知道这是否
有一个带有函数定义的文件bar.swift: func bar() { println("bar") } 以及一个以立即模式运行的脚本foo.swift: #!/usr/bin/xcrun s
我是一名优秀的程序员,十分优秀!