WKWebView LayoutConstraints问题 [英] WKWebView LayoutConstraints issue

问题描述

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.它加载第一页没有问题.

I have created a simple webview app. But there is a small problem and I can not fix it. It loads the first page without issue.

当我单击第一个输入时，程序崩溃，错误代码如下:

When I click to the first input, the program crashes and the error code is below:

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()
    }
}

我尝试了所有可以在Internet上找到的帮助，但是没有运气.

I have tried all help that I find on the Internet, but no luck.

推荐答案

通常，您应该遵循下一个流程

In general you should follow next flow

1. 将webView作为子视图添加到UIViewController的视图中(您可能会 已经在XIB或Storyboard中完成了
2. 在以下位置的webView和UIViewController的视图之间添加自动布局约束 代码或在Interface Builder中

3. 另外，请删除

1. Add webView as a subview to UIViewController's view (you might have done it in XIB or Storyboard)
2. Add Autolayout constraints between webView and UIViewController's view in code or in Interface Builder

3. Also, please remove

view.translatesAutoresizingMaskIntoConstraints=false

如果一切正常，请附加您的XIB或情节提要.

If everything about is OK, please attach your XIB or Storyboard.

更新 这是我的ViewController，仅显示WKWebView.

Update Here is my ViewController that shows WKWebView only.

    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

        }
    }

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