Form
A container for grouping controls used for data entry, such as in settings or inspectors
SwiftUI gives us a dedicated view type for this purpose, called Form. Forms are scrolling lists of static controls like text and images, but can also include user interactive controls like text fields, toggle switches, buttons, and more.
Declaration
struct Form<Content> where Content : View
Overview
SwiftUI applies platform-appropriate styling to views contained inside a form, to group them together. Form-specific styling applies to things like buttons, toggles, labels, lists, and more. Keep in mind that these stylings may be platform-specific. For example, forms apppear as grouped lists on iOS, and as aligned vertical stacks on macOS.
The following example shows a simple data entry form on iOS, grouped into two sections. The supporting types (NotifyMeAboutType and ProfileImageSize) and state variables (notifyMeAbout, profileImageSize, playNotificationSounds, and sendReadReceipts) are omitted for simplicity.
var body: some View {
NavigationView {
Form {
Section(header: Text("Notifications")) {
Picker("Notify Me About", selection: $notifyMeAbout) {
Text("Direct Messages").tag(NotifyMeAboutType.directMessages)
Text("Mentions").tag(NotifyMeAboutType.mentions)
Text("Anything").tag(NotifyMeAboutType.anything)
}
Toggle("Play notification sounds", isOn: $playNotificationSounds)
Toggle("Send read receipts", isOn: $sendReadReceipts)
}
Section(header: Text("User Profiles")) {
Picker("Profile Image Size", selection: $profileImageSize) {
Text("Large").tag(ProfileImageSize.large)
Text("Medium").tag(ProfileImageSize.medium)
Text("Small").tag(ProfileImageSize.small)
}
Button("Clear Image Cache") {}
}
}
}
}
截屏2021-09-27 上午8.56.51.png
Creating a Form
init(content: () -> Content)
Simple Example
1、 Form包含一个Text，可滚动
// 定义结构体ContentView，遵守View协议
struct ContentView: View {
// 定义计算属性body
// some View：表示返回的内容将遵守View协议
var body: some View {
// 返回一个具体类型的View
Form {
Text("Hello, World!")
}
}
}
效果：
form1.png
2、包含多个Text,但是最多10控件
struct ContentView: View {
var body: some View {
Form {
Text("Hello, World!")
Text("Hello, World!")
Text("Hello, World!")
Text("Hello, World!")
Text("Hello, World!")
}
}
}
form2.png
3、要想使用多个，可以使用Group进行分组，界面UI效果不变
struct ContentView: View {
var body: some View {
Form {
Group {
Text("Hello, World!")
Text("Hello, World!")
Text("Hello, World!")
}
Group {
Text("Hello, World!")
Text("Hello, World!")
Text("Hello, World!")
}
}
}
}
4、如果想明显看到区分群组，可以使用Section
struct ContentView: View {
var body: some View {
Form {
Section {
Text("Hello, World!")
Text("Hello, World!")
Text("Hello, World!")
}
Section {
Text("Hello, World!")
Text("Hello, World!")
Text("Hello, World!")
}
}
}
}
form3.png
设置header和footer视图
struct ContentView: View {
var body: some View {
Form {
Section(header: Text("Section 1")) {
Text("Hello, World!")
Text("Hello, World!")
Text("Hello, World!")
}
Section(header: Text("Section 2")) {
ForEach(0..<5) {
Text("Dynamic row \($0)")
}
}
Section(header: Text("Section 3"), footer: Text("Section 3 footer")) {
Text("Static row")
Text("Static row")
}
}
}
}
form5.png
5、使用ForEach循环创建view
struct ContentView: View {
var body: some View {
Form {
ForEach(0..<100) {
Text("Row: \($0)")
}
}
}
}
form4.png
6、通过NavigationView和Form布局一个简单的设置界面
struct ContentView: View {
// 用户名
@State var username: String = ""
@State var isPrivate: Bool = true
@State var notificationsEnabled: Bool = false
@State private var previewIndex = 0
var previewOptions = ["Always","When Unlocked", "Never"]
var body: some View {
NavigationView {
Form {
Section(header: Text("PROFILE")) {
TextField("Username", text: $username)
Toggle(isOn: $isPrivate) {
Text("Private Account")
}
}
Section(header: Text("NOTIFICATIONS")) {
Toggle(isOn: $notificationsEnabled) {
Text("Enabled")
}
Picker(selection: $previewIndex, label: Text("Show Previews")) {
ForEach(0 ..< previewOptions.count) {
Text(self.previewOptions[$0])
}
}
}
Section(header: Text("ABOUT")) {
HStack {
Text("Version")
Spacer()
Text("2.2.1")
}
}
Section {
Button(action: {
print("Perform an action here...")
}) {
Text("Reset All Settings")
}
}
}
.navigationBarTitle("Settings")
}
}
}
Simulator Screen Shot - iPhone 12 - 2021-09-27 at 09.05.57.png
具体详情可查看SwiftUI Form tutorial – how to create and use Form in SwiftUI
如果要去除两边间距，可以将From改为List，并添加listStyle
struct ContentView: View {
// 用户名
@State var username: String = ""
@State var isPrivate: Bool = true
@State var notificationsEnabled: Bool = false
@State private var previewIndex = 0
var previewOptions = ["Always","When Unlocked", "Never"]
var body: some View {
NavigationView {
List {
Section(header: Text("PROFILE")) {
TextField("Username", text: $username)
Toggle(isOn: $isPrivate) {
Text("Private Account")
}
}
Section(header: Text("NOTIFICATIONS")) {
Toggle(isOn: $notificationsEnabled) {
Text("Enabled")
}
Picker(selection: $previewIndex, label: Text("Show Previews")) {
ForEach(0 ..< previewOptions.count) {
Text(self.previewOptions[$0])
}
}
}
Section(header: Text("ABOUT")) {
HStack {
Text("Version")
Spacer()
Text("2.2.1")
}
}
Section {
Button(action: {
print("Perform an action here...")
}) {
Text("Reset All Settings")
}
}
}.listStyle(GroupedListStyle()).navigationBarTitle("Settings")
}
}
}
form6.png
网友评论