swiftui

swiftui

Before SwiftUI 2, there was no way of creating a toolbar like in UIKit, so I decided to implement my own. It is available on GitHub as a Swift package called ToolbarSUI.

在SwiftUI 2之前，无法像在UIKit中那样创建工具栏，因此我决定实现自己的工具栏。 它可以在GitHub上作为称为ToolbarSUI的Swift软件包获得。

The main component of the package is a SwiftUI view called ToolbarView. Here is the code:

该软件包的主要组件是一个称为ToolbarView的SwiftUI视图。 这是代码：

// // ToolbarView.swift // // Created by Keith Lander on 24/07/2020. // Copyright © 2020 Keith Lander. All rights reserved. // import SwiftUI #if os(iOS) || targetEnvironment(macCatalyst) public struct ToolbarView : View { @State private var selectedIndex = -1 public let items: [ToolbarItem] public let action: (Int)->Void public var label: String? /// View Initialiser /// - Parameters: /// - label: Test to appear on the left of the toolbar. Omit if not needed. /// - items: An array of ToolbarItems. Each entry specifies a button. /// - action: This is a closure that manages button presses. It has a single Int argument /// with values in the range 0 to the number of buttons. public init(label: String? = nil, items: [ToolbarItem], action:@escaping (Int)->Void) { self.items = items self.action = action self.label = label } func itemView(at index: Int) -> some View { Button(action: { withAnimation { self.action(index) } }) { ToolbarItemView(selected: self.$selectedIndex, index: index, item: items[index]) }.disabled(items[index].disabled) } public var body: some View { HStack(alignment: .bottom) { HStack(alignment: .center) { if label != nil { Text(label!) .foregroundColor(Color.gray) .padding(EdgeInsets(top: 0, leading: 10, bottom: 0, trailing: 0)) } ForEach(0..<items.count) { index in Spacer() self.itemView(at: index) Spacer() } } } .modifier(RectangleOverlay()) } } #endif

As you can see, the view initialiser takes three arguments:

如您所见，视图初始化程序采用三个参数：

Text for a label to appear on the left of the toolbar. If you don’t want a label, leave this blank.

标签的文本显示在工具栏的左侧。 如果您不想要标签，请将其留空。

An array of ToolbarItems.

ToolbarItems的数组。

An action closure.

动作关闭。

Here is an example of the view in use:

这是使用中的视图的示例：

ToolbarView(label:self.textFile.versionLabel(), items: [ToolbarItem(icon: "chevron.left.circle", title: "Show previous version", disabled: self.textFile.atFirstVersion()), ToolbarItem(icon: "chevron.right.circle", title: "Show next version", disabled: self.textFile.atLastVersion()), ToolbarItem(icon: "plus.circle", title: "Duplicate this version", disabled: false), ToolbarItem(icon: "trash.circle", title: "Delete this version", disabled: self.textFile.versions!.count <= 1)] ) { (action) in if action == 0 { self.textFile.changeVersion(by: -1) } else if action == 1 { self.textFile.changeVersion(by: 1) } else { self.textFile.perform(action) } }

Here is what it looks like:

看起来是这样的：

Photo by the author. 图片由作者提供。

Each button in the toolbar is defined by a ToolbarItem, as shown below:

工具栏中的每个按钮均由ToolbarItem定义，如下所示：

// // ToolbarItem.swift // // Created by Keith Lander on 24/07/2020. // Copyright © 2020 Keith Lander. All rights reserved. // import SwiftUI #if os(iOS) || targetEnvironment(macCatalyst) public struct ToolbarItem { public let icon: Image public let title: String public let disabled:Bool public init(icon: Image, title: String, disabled: Bool){ self.icon = icon self.title = title self.disabled = disabled } public init(icon: String, title: String, disabled: Bool) { self = ToolbarItem(icon: Image(systemName: icon), title: title, disabled: disabled) } } #endif

Each entry consists of three items:

每个条目包含三个项目：

The name of an image in SF Symbols.

SF Symbols中图像的名称。 A title. This is not displayed but is there for accessibility purposes. It should be a good description of the button.

一个标题。 这不会显示，但是可以访问。 它应该是按钮的良好描述。

A boolean value that determines the state of the button — true for active, false otherwise. As you can see, its value is changed whenever the view is updated.

一个布尔值，它确定按钮的状态- true表示有效状态， false否则。 如您所见，只要更新视图，它的值就会更改。

Thanks for reading. I hope you find the package useful. If you have any problems, please post an issue on GitHub.

谢谢阅读。 我希望您觉得该软件包有用。 如果您有任何问题，请在GitHub上发布问题。

翻译自: https://medium.com/better-programming/a-swiftui-toolbar-777523c03b7d

swiftui

相关资源：macOS SwiftUI 三栏App架构动态修改标题和设置工具栏