在 Swift 游乐场中更改实时视图的框架

您需要定义preferredContentSize的UIHostingController，如下所示：

import PlaygroundSupport
import SwiftUI

public struct PlaygroundRootView: View {
    public var body: some View {
        Rectangle()
            .frame(width: 200, height: 100, alignment: .center)
            .foregroundColor(Color.blue.opacity(0.7))
            .cornerRadius(20)
     }
}

let host = UIHostingController(rootView: PlaygroundRootView())
host.preferredContentSize = CGSize(width: 600, height: 600)
PlaygroundPage.current.liveView = host

结果