iOS Playground 不显示 UI 预览 [英] iOS Playground doesn't show UI preview

问题描述

我使用 XCode 7.1 创建了一个简单的 Playground，并且输入了以下简单代码:

导入 UIKit导入 XCPlaygroundvar str = "你好，游乐场"让 color = UIColor (red: 1 , green: 1 , blue: 0 , alpha: 0 )让视图 = UIView()view.backgroundColor = UIColo (colorLiteralRed: 1 , green: 0 , blue: 0 , alpha: 0 )view.frame = CGRect (x: 0 ,y: 0 ,width: 100 ,height: 100 )let label = UILabel (frame: CGRect (x: 5 , y: 5 , width: 50 , height: 20 ))标签.text = strview.addSubview(标签)

playground 运行时不显示 UIKit 对象预览，只显示调试信息:

我做错了什么?

解决方案

打开预览面板:View > Assistant Editor > Show Assistant Editor

然后在你的代码中:

导入 PlaygroundSupportPlaygroundPage.current.liveView = 查看

<块引用>

别忘了给你的视图一个可见的框架.

<小时>

Ps:在 Xcode 9 之后，你可以创建一个默认视图的 Playground

I've created a simple playground with XCode 7.1 and I've typed this simple code:

import UIKit 
import XCPlayground 

var str = "Hello, playground" 

let color = UIColor (red: 1 , green: 1 , blue: 0 , alpha: 0 ) 

let view = UIView() 
view.backgroundColor = UIColo (colorLiteralRed: 1 , green: 0 , blue: 0 , alpha: 0 ) 

view.frame = CGRect (x: 0 ,y: 0 ,width: 100 ,height: 100 ) 

let label = UILabel (frame: CGRect (x: 5 , y: 5 , width: 50 , height: 20 )) 

label.text = str 

view.addSubview(label) 

When the playground runs, it doesn't show UIKit object preview, but only debug information:

What am I doing wrong?

解决方案

Open the preview panel: View > Assistant Editor > Show Assistant Editor

Then in your code:

import PlaygroundSupport
PlaygroundPage.current.liveView = view

Don't forget to give your view a visible frame.

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Ps: after Xcode 9, you can create a playground with default view

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