Xcode 预览错误 - '@objc' 只能应用于类的扩展
问题描述 投票：0回答：1
我使用的是 Xcode 14.2，其中包含 SwiftUI 文件和 Objective-C 文件，该文件使用
NotificationCenter'@objc'只能应用于类的扩展
如何在 iPhone8 上查看此内容，以便修复布局，使所有内容都适合屏幕？
快速代码：
import Foundation
import SwiftUI
@objc public protocol CMWUploadViewV2Delegate: NSObjectProtocol {
@objc func uploadOKButtonPushed()
@objc func uploadAbortButtonPushed()
@objc func uploadErrorLogButtonPushed()
@objc func uploadRetryButtonPushed()
}
@objc class CMWSTUploadViewV2Controller: UIViewController {
@IBOutlet var ProgressBarView: UIView!
// embed SwiftUI into the UIKit storyboard view controller
override func viewDidLoad() {
super.viewDidLoad()
let childView = UIHostingController(rootView: ContentView())
addChild(childView)
childView.view.frame = ProgressBarView.bounds
ProgressBarView.addSubview(childView.view)
childView.didMove(toParent: self)
}
@objc weak var delegate: CMWUploadViewV2Delegate?
//creating function for dictionary to store changes and create notification
//This takes a value between 0 and 1
@objc func UpdateUploadProgress(progressValue: Float)
{
//First, we need to normalize the value which is between 0 and 0.99 to 0 and 0.8999996
let normalizedValue = progressValue * 0.8999996
let valueUpdate:[String: Float] = ["ProgressValue": normalizedValue]
NotificationCenter.default.post(name:NSNotification.Name("COM.CMW.UpdateUploadProgress"), object: nil, userInfo:valueUpdate)
}
@objc func UpdateInitialText(InitialTextParameter: String)
{
let textUpdate:[String: String] = ["InitialTextParameter": InitialTextParameter]
NotificationCenter.default.post(name:NSNotification.Name("COM.CMW.UpdateInitialText"), object: nil, userInfo:textUpdate)
}
@objc func UpdateAddressText(AddressTextParameter: String)
{
let textUpdate:[String: String] = ["AddressTextParameter": AddressTextParameter]
NotificationCenter.default.post(name:NSNotification.Name("COM.CMW.UpdateAddressText"), object: nil, userInfo:textUpdate)
}
@objc func UpdateOrangeText(OrangeTextParameter: String)
{
let textUpdate:[String: String] = ["OrangeTextParameter": OrangeTextParameter]
NotificationCenter.default.post(name:NSNotification.Name("COM.CMW.UpdateOrangeText"), object: nil, userInfo:textUpdate)
}
@objc func UpdateGreySubText(GreySubTextParameter: String)
{
let textUpdate:[String: String] = ["GreySubTextParameter": GreySubTextParameter]
NotificationCenter.default.post(name:NSNotification.Name("COM.CMW.UpdateGreySubText"), object: nil, userInfo:textUpdate)
}
@objc func UpdateControllerTypeText(ControllerTypeTextParameter: String)
{
let textUpdate:[String: String] = ["ControllerTypeTextParameter": ControllerTypeTextParameter]
NotificationCenter.default.post(name:NSNotification.Name("COM.CMW.UpdateControllerTypeText"), object: nil, userInfo:textUpdate)
}
@objc func UpdateConnectionTypeText(ConnectionTypeTextParameter: String)
{
let textUpdate:[String: String] = ["ConnectionTypeTextParameter": ConnectionTypeTextParameter]
NotificationCenter.default.post(name:NSNotification.Name("COM.CMW.UpdateConnectionTypeText"), object: nil, userInfo:textUpdate)
}
@objc func UpdateStatusText(StatusTextParameter: String)
{
let textUpdate:[String: String] = ["StatusTextParameter": StatusTextParameter]
NotificationCenter.default.post(name:NSNotification.Name("COM.CMW.UpdateStatusText"), object: nil, userInfo:textUpdate)
}
struct ContentView: View {
//creating vars
@State var progressValue: Float = 0.3
//let timer = Timer.publish(every: 1, on: .main, in: .common).autoconnect()
@State private var degress: Double = -110
//@State var GreySubText = ""
let label = UILabel()
@State var buttonText1 = ""
@State var buttonText2 = ""
@State var controllerTypeText = ""
@State var connectionTypeText = "CAN"
@State var statusText = "Status text here"
@State var fourLinesText = "More status text here. Controller responding. This text will be 4 lines in length. 1234567891011121314151617181920. Controller responding. This text will be 4 lines in length. 1234567891011121314151617181920. Controller responding. This text will be 4 lines in length. 1234567891011121314151617181920"
@State var initialText = "Resetting to upload mode."
//setting up notification center to listen to addresses
let publisher = NotificationCenter.default.publisher(for: NSNotification.Name("COM.CMW.UpdateUploadProgress"))
let publisher8 = NotificationCenter.default.publisher(for: NSNotification.Name("COM.CMW.UpdateInitialText"))
//let publisher6 = NotificationCenter.default.publisher(for: NSNotification.Name("COM.CMW.UpdateAddressText"))
//let publisher7 = NotificationCenter.default.publisher(for: NSNotification.Name("COM.CMW.UpdateOrangeText"))
//let publisher5 = NotificationCenter.default.publisher(for: NSNotification.Name("COM.CMW.UpdateGreySubText"))
let publisher2 = NotificationCenter.default.publisher(for: NSNotification.Name("COM.CMW.UpdateControllerTypeText"))
let publisher3 = NotificationCenter.default.publisher(for: NSNotification.Name("COM.CMW.UpdateConnectionTypeText"))
let publisher4 = NotificationCenter.default.publisher(for: NSNotification.Name("COM.CMW.UpdateStatusText"))
//display
var body: some View {
VStack {
Spacer()
.frame(height: 70)
if #available(iOS 16.0, *) {
Label(initialText, systemImage: "clock")
.font(.title)
.foregroundColor(Color(hex: "000"))
.fontWeight(.bold)
.onReceive(publisher8) { obj in
let initialTextVal = obj.userInfo?["InitialTextParameter"] as? String
initialText = initialTextVal!
}
} else {
// Fallback on earlier versions
Label(initialText, systemImage: "clock")
.font(.title)
.foregroundColor(Color(hex: "000"))
.onReceive(publisher8) { obj in
let initialTextVal = obj.userInfo?["InitialTextParameter"] as? String
initialText = initialTextVal!
}
}
ZStack{
//background rectangle
RoundedRectangle(cornerRadius: 25)
.fill(Color(hex: "494949"))
.frame(width: 300, height: 300)
ProgressBar(progress: self.$progressValue)
.frame(width: 250.0, height: 250.0)
.padding(40.0)
.onReceive(publisher) { obj in
let progVal = obj.userInfo?["ProgressValue"] as? Float
progressValue = progVal!
}
ProgressBarTriangle(progress: self.$progressValue).frame(width: 280.0, height: 290.0).rotationEffect(.degrees(degress), anchor: .bottom)
.offset(x: 0, y: -150)
}
//***Controller, Connection, and Status labels/text
Spacer()
.frame(height: 20)
VStack(alignment :.leading, spacing: 30) {
HStack {
if #available(iOS 16.0, *) {
Label("Controller type:", image: "ControllerIcon")
.foregroundColor(Color(hex: "000"))
.fontWeight(.bold)
} else {
// Fallback on earlier versions
Label("Controller type:", image: "ControllerIcon")
.foregroundColor(Color(hex: "000"))
}
Text(controllerTypeText)
//app crashes when following code active:
//onReceive(publisher2) { obj in
//let controllerTextVal = //obj.userInfo?["ControllerTypeTextParameter"] as? String
//controllerTypeText = controllerTextVal!
//}
}
HStack {
if #available(iOS 16.0, *) {
Label("Connection type:", image: "CANIconSmall")
.foregroundColor(Color(hex: "000"))
.fontWeight(.bold)
} else {
// Fallback on earlier versions
Label("Connection type:", image: "CANIconSmall")
.foregroundColor(Color(hex: "000"))
}
Text(connectionTypeText)
.onReceive(publisher3) { obj in
let connectionTextVal = obj.userInfo?["ConnectionTypeTextParameter"] as? String
connectionTypeText = connectionTextVal!
}
}
HStack {
if #available(iOS 16.0, *) {
Label("Status:", image: "StatusIcon")
.foregroundColor(Color(hex: "000"))
.fontWeight(.bold)
} else {
// Fallback on earlier versions
Label("Status:", image: "StatusIcon")
.foregroundColor(Color(hex: "000"))
}
}
//four lines of status text
Text(fourLinesText)
.foregroundColor(Color(hex: "000"))
.lineLimit(4)
.multilineTextAlignment(.leading)
.onReceive(publisher4) { obj in
let statusTextVal = obj.userInfo?["StatusTextParameter"] as? String
fourLinesText = statusTextVal!
}
Spacer()
}
.padding(.leading, 20)
.padding(.trailing, 20)
}
}
public struct ProgressBar: View {
//creating vars
@Binding var progress: Float
@State var addressText = "0x1c000"
@State var orangeText = "Orange Text"
@State var GreySubText = ""
let publisher7 = NotificationCenter.default.publisher(for:
NSNotification.Name("COM.CMW.UpdateOrangeText"))
let publisher6 = NotificationCenter.default.publisher(for: NSNotification.Name("COM.CMW.UpdateAddressText"))
let publisher5 = NotificationCenter.default.publisher(for: NSNotification.Name("COM.CMW.UpdateGreySubText"))
public func UpdateProgressValue(progressValue: Float)
{
progress = progressValue
}
var body: some View {
VStack (alignment :.center, spacing: 30){
HStack {
Label("Address:", systemImage: "target")
.foregroundColor(Color(hex: "8f8f8f"))
.padding(.top, 15)
Text(addressText)
.foregroundColor(Color(hex: "8f8f8f"))
.padding(.top, 15)
.onReceive(publisher6) { obj in
let addressTextVal = obj.userInfo?["AddressTextParameter"] as? String
addressText = addressTextVal!
}
}
ZStack {
Circle()
.trim(from: 0.35, to: 0.85)
.stroke(style: StrokeStyle(lineWidth: 12.0, lineCap: .round, lineJoin: .round))
.opacity(0.3)
.foregroundColor(Color.gray)
.rotationEffect(.degrees(54.5))
Circle()
.trim(from: 0.35, to: CGFloat(self.progress))
.stroke(style: StrokeStyle(lineWidth: 12.0, lineCap: .round, lineJoin: .round))
.fill(AngularGradient(gradient: Gradient(stops: [
.init(color: Color.init(hex: "daff00"), location: 0.39000002),
.init(color: Color.init(hex: "00ff04"), location: 0.5999999),
.init(color: Color.init(hex: "32E1A0"), location: 0.8099997)]), center: .center))
.rotationEffect(.degrees(54.5))
VStack(alignment :.center, spacing: 10) {
Text("824").font(Font.system(size: 44)).bold().foregroundColor(Color.init(hex: "ffffff"))
if #available(iOS 16.0, *) {
Label(orangeText, systemImage: "clock")
.foregroundColor(Color(hex: "FF6600"))
.fontWeight(.bold)
.onReceive(publisher7) { obj in
let statusTextVal = obj.userInfo?["OrangeTextParameter"] as? String
orangeText = statusTextVal!
}
} else {
// Fallback on earlier versions
Label(orangeText, systemImage: "clock")
.foregroundColor(Color(hex: "FF6600"))
.onReceive(publisher7) { obj in
let statusTextVal = obj.userInfo?["OrangeTextParameter"] as? String
orangeText = statusTextVal!
}
}
Text(GreySubText)
.foregroundColor(Color(hex: "8f8f8f"))
.multilineTextAlignment(.center)
.onReceive(publisher5) { obj in
let GreySubTextVal = obj.userInfo?["GreySubTextParameter"] as? String
GreySubText = GreySubTextVal!
}
}
}
}
}
}
struct ProgressBarTriangle: View {
@Binding var progress: Float
var body: some View {
ZStack {
Image("triangle").resizable().frame(width: 10, height: 10, alignment: .center)
}
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
}
extension Color {
init(hex: String) {
let hex = hex.trimmingCharacters(in: CharacterSet.alphanumerics.inverted)
var int: UInt64 = 0
Scanner(string: hex).scanHexInt64(&int)
let a, r, g, b: UInt64
switch hex.count {
case 3: // RGB (12-bit)
(a, r, g, b) = (255, (int >> 8) * 17, (int >> 4 & 0xF) * 17, (int & 0xF) * 17)
case 6: // RGB (24-bit)
(a, r, g, b) = (255, int >> 16, int >> 8 & 0xFF, int & 0xFF)
case 8: // ARGB (32-bit)
(a, r, g, b) = (int >> 24, int >> 16 & 0xFF, int >> 8 & 0xFF, int & 0xFF)
default:
(a, r, g, b) = (1, 1, 1, 0)
}
self.init(
.sRGB,
red: Double(r) / 255,
green: Double(g) / 255,
blue: Double(b) / 255,
opacity: Double(a) / 255
)
}
}
目标C代码：
-(void)summerTestUploadViewController
{
CMWSTUploadViewV2Controller* myView = [[UIStoryboard storyboardWithName:@"MainStoryboard_iPhone" bundle:nil] instantiateViewControllerWithIdentifier:@"ID_CMW_UPLOADVIEWV2_VIEW"];
// myView.delegate = self;
[self presentViewController:myView animated:YES completion:^{
[myView UpdateUploadProgressWithProgressValue:0.7];
[myView UpdateInitialTextWithInitialTextParameter:@"Initial text here"];
[myView UpdateAddressTextWithAddressTextParameter:@"Address text here"];
[myView UpdateOrangeTextWithOrangeTextParameter:@"Orange text here"];
[myView UpdateGreySubTextWithGreySubTextParameter:@"Grey sub text here"];
[myView UpdateControllerTypeTextWithControllerTypeTextParameter:@"Controller text here"];
[myView UpdateConnectionTypeTextWithConnectionTypeTextParameter:@"Connection text here"];
[myView UpdateStatusTextWithStatusTextParameter:@"Status text here. 4 lines of text will be allowed in this area. 4 lines of text will be allowed in this area. 4 lines of text will be allowed in this area. 4 lines of text will be allowed in this area. 4 lines of text will be allowed in this area."];
}];
}
1个回答
0
投票
投票
要解决 SwiftUI 预览不显示的问题以及 Xcode 14.2 中有关“@objc”的错误消息，并在 iPhone 8 上查看布局以进行调整，以下是您可以执行的操作的摘要：
修复“@objc”错误：错误消息““@objc”只能应用于类的扩展”表明代码中使用“@objc”属性的方式不匹配。确保它们仅应用于 Objective-C 兼容类的成员或此类类的扩展。
在 iPhone 8 上预览:
- 使用 iPhone 8 模拟器：不要依赖 SwiftUI 预览，而是在 iPhone 8 模拟器上运行您的应用程序，以查看它在该特定设备上的外观和行为。这可以通过从模拟器列表中选择 iPhone 8 直接从 Xcode 完成。
- 调整较小屏幕的布局：如果 iPhone 8 上的文本被截断，则表明您的布局可能无法响应较小的屏幕尺寸。利用 SwiftUI 的自适应布局功能，例如
、GeometryReader
或flexible frames
，使您的 UI 元素动态调整以适应不同的屏幕尺寸。ScrollView - 在模拟器中调试：在模拟器中运行应用程序时使用 Xcode 的调试工具来检查 UI 并确定导致文本被截断的原因。您可以使用断点并查看 UI 层次结构，以更好地了解布局问题。
一般提示：
- 针对多种设备进行优化：设计您的 SwiftUI 视图，使其灵活并响应不同的屏幕尺寸和方向。这确保了所有设备上一致的用户体验。
- 定期测试：定期在各种设备和模拟器上测试您的应用程序，以便在开发过程的早期发现并修复布局问题。
通过修复代码中的“@objc”用法并使用 iPhone 8 模拟器测试和调整布局，您应该能够有效解决文本截断问题。请记住定期在不同设备上进行测试，以确保兼容性和良好的用户体验。
让我知道它是否对您有用。 :)
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