One of the reasons why the WebView web page cannot be opened (and some WebView problem records encountered by myself)

prospect

WebView stay loadUrl When , There may be a problem that the web page cannot be opened , There are a lot of such problems on the Internet , But maybe after looking around, there is no answer you want , Maybe one possibility is that you usually OkHttp The request is not ignored but is configuring WebView I ignored , Please read the last article directly .

cause

I'm replacing x5WebView When I met this problem , This is the second replacement of , The first replacement did not encounter any obstacles at all , If some students encounter some configuration problems , You can go to Tencent browsing service to check the steps Portal

The problems I encountered are shown in the figure , also I tried to load Baidu home page directly , It can't be opened ！

The process

Someone on the Internet said it was android:networkSecurityConfig="" There is no configuration problem , Of course not , Because these configurations have been configured before , I didn't write this project from scratch , Just take it to maintain and modify it . Follow this train of thought , I carefully compared some on the Internet WebView Configuration problem , These big differences are not bad ,domStorageEnabled = true It must have been set , None of those key configurations are missing , What could be the reason ？

In the process of replacement, I wrote a new one myself WebView Base class , I didn't look at the previous code , Just take it over and turn it over , Find yourself rewriting one less method , Replace this method x5WebView already WebView I didn't see it in the basic settings , But I thought about it , You do encounter this problem when sending network requests , Namely onReceivedSslError() Method , newly build WebViewClient This method is not rewritten ！ Maybe we're doing demo I didn't rewrite it, but there's no problem , But for finished product projects , If this method is not rewritten , It should be impossible to pass .

Android Application WebView visit https SSL Certificate web page ,Google Play Always report WebView Of onReceivedSslError error (ERR_SSL_PROTOCOL_ERROR ). To avoid Google security warnings , To rewrite WebView Of onReceivedSslError Method , At this point, a pop-up box will prompt the user , Whether to ignore SSL error , Continue to visit the web page .

Baidu said .

The specific method can be seen from the old man's writing , It's still very clear Portal

What you do depends on what you do , I must be direct here SslErrorHandler.proceed 了 , There's nothing else to deal with

Treatment method

rewrite WebView Set in the WebViewClient Of onReceivedSslError() Method . Ignore ssl Certificate error , Carry on ,

		webViewClient = object : WebViewClient() {
    

                override fun onReceivedSslError(p0: WebView?, p1: SslErrorHandler?, p2: SslError?) {
    
                    p1?.proceed()
                }

                override fun shouldOverrideUrlLoading(view: WebView?, url: String?): Boolean {
    
                    //  Rewriting this method indicates that the link in the web page is still in the current webview Jump in , Don't jump to the browser 
                   
                }
            }

Other problems encountered

The search box cursor is missing
After the replacement, there is a search page , When you jump in, you should pop up the keyboard , The cursor is displayed in the search box , But the ideal is always beautiful , The display is not like this . Check ,mWebView.requestFocus() Set , Re examination

	android:focusable="true"
    android:focusableInTouchMode="true"

WebView The change property has been set . It's strange , It didn't work ？
No , The keyboard pops out , But the cursor doesn't show , Probability is a focus problem , Fortunately, this problem is not very troublesome , Compared with Baidu's previous articles, there is a case to solve , Portal ！ Is to put it on xml The available code for setting focus in WebView In the parent layout of , such as FrameLayout in , Run again , solve the problem .

Sliding compression problem
This problem bothered me for more than half a year , Because of this problem , I have been urged twice by the leader , The coincidence was solved , Fortunately, too web The end personnel actively cooperate .
Is to load the local static list page or the list page of some network requests , Sliding will be compressed , It's a very serious kind of , It will also appear on the real machine .
When something goes wrong , On the Internet, it is said that it is the problem of turning on hardware acceleration , But I made it clear , Didn't drive ！ It is not turned on under various configurations ,app To Activity To view. I compared uncompressed WebView Set up , Two comparisons were made , In fact, there is no big problem , After copying, it will still be compressed , Then for the first time x5 after , Still compress , But it's not that good . Later, I will the static list page html Copy the content , I wrote a html, There are no styles and js, Put in... Again WebView, A magical scene appeared , No compression , Whether native or x5, All run smoothly ！
And then web The style of the end has been modified , After he cancelled some style , Really no longer compress , But I can't , This style is used globally , It'll be a while and a half. It can't be cancelled （ If there are similar problems , It can make web Check first , After all WebView The only settings are those , Maybe not Native The problem of ）.
This settlement is also a coincidence , Replaced the latest x5 after , I cancelled all settings related to acceleration according to the document , By default , Use a style that will cause compression , The simulator will compress slightly , But the real machine won't , I'll send the specific configuration below , It's a muddle headed way to solve this problem . summary ：html Style a pot with a part on the back , Another part , It should still be with WebView of . At present, I am app Turn on hardware acceleration , however view The layer is not set , I have set this part in comparison , This is not the key to solving the problem . It's just for your reference , What causes the setting and how to solve it , I am also in a state where I can't touch my head .
To rush ！

	init {
    
        //WebSettings Set up 
        settings.apply {
    
            // Set the default encoding format to “UTF-8”
            defaultTextEncodingName = "UTF-8"
            // Set up DOM Storage available 
            domStorageEnabled = true
            //js You can use 
            javaScriptEnabled = true
            // Support js Open a new window 
            javaScriptCanOpenWindowsAutomatically = true
            // Support automatic loading of pictures 
            loadsImagesAutomatically = true
            // Set the availability of database storage 
            databaseEnabled = true
            // stay File Under domain , Be able to execute arbitrary JavaScript Code , Cross domain access of the same origin policy can access private directory files and so on 
            allowFileAccess = true
            blockNetworkImage = false
            blockNetworkLoads = false
            // Set application cache availability 
            setAppCacheEnabled(true)
            // Set cache path 
            setAppCachePath(context.applicationContext.getDir("cache", Context.MODE_PRIVATE).path)
            // Cache mode ： Do not use cache 
            cacheMode = WebSettings.LOAD_NO_CACHE
            // Support page scaling 
            setSupportZoom(true)
            // Zoom is controlled using the zoom in and zoom out buttons 
            builtInZoomControls = true
            // Do not display the boundary slider 
            displayZoomControls = false
            // Use browser components , It is recommended to use 
            useWideViewPort = true
            loadWithOverviewMode = true
            // Enable geolocation 
            setGeolocationEnabled(true)
            // Support Http And Https Mixed mode 
            mixedContentMode = 0
            // Set whether to allow  file url  Loaded  Js Code to read other local files （ There are risks , Non internal pages are recommended to be closed ）
            setAllowFileAccessFromFileURLs(true)
            // Set whether to allow  file url  Loaded  Javascript  You can access other sources ( Include http、https Etc )（ There are risks , Non internal pages are recommended to be closed ）
            setAllowUniversalAccessFromFileURLs(true)
            // Adjust thread priority （ Generally, adjustment is not recommended , Default normal）
            setRenderPriority(WebSettings.RenderPriority.HIGH)
            // Cancel the vertical and horizontal sliding bars 
            isVerticalScrollBarEnabled = false
            isHorizontalScrollBarEnabled = false
            // Elastic sliding is not allowed 
            overScrollMode = View.OVER_SCROLL_NEVER
            // Hardware acceleration 
            //setLayerType(View.LAYER_TYPE_HARDWARE, null)
            webViewClient = object : WebViewClient() {
    

                override fun onReceivedSslError(p0: WebView?, p1: SslErrorHandler?, p2: SslError?) {
    
                    p1?.proceed()
                }

                override fun shouldOverrideUrlLoading(view: WebView?, url: String?): Boolean {
    
                    //  Rewriting this method indicates that the link in the web page is still in the current webview Jump in , Don't jump to the browser 
                    return super.shouldOverrideUrlLoading(view, url)
                }
            }
            addJavascriptInterface(javascriptInterface, JS_OBJ_NAME)
        }
    }