WKWebView LayoutConstraints问题

Question

我创建了一个简单的webview应用程序。但是有一个小问题，我无法解决它。它加载第一页没有问题。

当我点击第一个输入时，程序崩溃，错误代码如下：

2017-10-28 23:50:54.289690+0400 BFI Schools[68425:3885613] [LayoutConstraints] Unable to simultaneously satisfy constraints.
Probably at least one of the constraints in the following list is one you don't want. 
Try this: 
    (1) look at each constraint and try to figure out which you don't expect; 
    (2) find the code that added the unwanted constraint or constraints and fix it. 
(Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand, refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints) 

我的代码如下：

//
//  ViewController.swift
//  BFI Schools
//
//  Created by Kamandar Abdullayev on 10/28/17.
//  Copyright © 2017 ROOM404.AZ. All rights reserved.
//

import UIKit
import WebKit

class ViewController: UIViewController , UIWebViewDelegate {
    @IBOutlet weak var webView: UIWebView!
    @IBOutlet weak var spinner: UIActivityIndicatorView!

    override func viewDidLoad() {
        super.viewDidLoad()

        view.translatesAutoresizingMaskIntoConstraints=false

        let url = URL(string: "https://www.parent.e-hism.co")!
        let request = URLRequest(url: url)

        if Reachability.isConnectedToNetwork() == true {
            webView.loadRequest(request)
        } else {
            let alert = UIAlertView(title: "No Internet Connection", message: "Make sure your device is connected to the internet.", delegate: nil, cancelButtonTitle: "OK")
            alert.show()
        }
    }

    func webViewDidStartLoad(_ : UIWebView) {
        spinner.startAnimating()
    }

    func webViewDidFinishLoad(_ : UIWebView) {
        spinner.stopAnimating()
    }
}

我已经尝试过在互联网上找到的所有帮助，但没有运气。

Answer 1

一般来说，你应该遵循下一个流程

1. 将webView作为子视图添加到UIViewController的视图中（您可以 已在XIB或Storyboard中完成）
2. 在webView和UIViewController的视图中添加Autolayout约束 代码或在Interface Builder中

3. 另外，请删除

   view.translatesAutoresizingMaskIntoConstraints=false

如果一切正常，请附上您的XIB或故事板。

<强>更新 这是我的ViewController，仅显示WKWebView。

    class ViewController: UIViewController {

        lazy var webView: WKWebView = {
            let webView = WKWebView(frame: .zero)
            webView.translatesAutoresizingMaskIntoConstraints = false
            return webView
        }()

        override func viewDidLoad() {
            super.viewDidLoad()

            // layout code
            view.addSubview(webView)
            view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|[webView]|", options: [], metrics: nil, views: ["webView": webView]))
            view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|[webView]|", options: [], metrics: nil, views: ["webView": webView]))

            // and then code to load request

        }
    }

Answer 2

值得注意的是，很多人都会遇到这种情况。我有一个干净的项目正在运行，没有其他控件并且遇到同样的问题：点击搜索（键盘弹出窗口）时的布局限制。

这可能表示为iOS 11错误：WKWebView constrains issue when keyboard pops up

Answer 3

根据以下来自Reveal的记录，这似乎是Apple代码中的自动版式问题。我敢打赌他们会在某个时候解决它。