Android WebView randomly doesn't show content for the same link - android

I have a link to the PDF or XML file. By default, a web view doesn't render such links. From another StackOverflow post, I figured out I need to wrap by link by google doc or google drive link (http://docs.google.com/viewer?url=myPDFLink). It works, the web view displays content but not in all cases. For the same link, the content randomly might be not displayed or be displayed. If the page is not displayed I can just retry several times and content displays. Cannot find a reason for such behavior. Even if the web view is blank, the onPageFinished callback is being called but not any error callbacks.
Update: onPageStarted is not being called but onPageFinished is being
WebViewClient:
val webViewClient = object : WebViewClient() {
override fun onPageStarted(view: WebView, url: String, favicon: Bitmap?) {
super.onPageStarted(view, url, favicon)
updateOnBackPressedCallbackState()
toolbarActivity?.setToolBarTitle(url)
onPageStateListener?.onPageStarted(view, url)
}
override fun onPageFinished(view: WebView, url: String) {
super.onPageFinished(view, url)
progressBar?.visibility = View.GONE
toolbarActivity?.setToolBarTitle(view.title)
onPageStateListener?.onPageFinished(view)
}
override fun onReceivedError(
view: WebView?,
errorCode: Int,
description: String?,
failingUrl: String?
) {
super.onReceivedError(view, errorCode, description, failingUrl)
}
override fun onReceivedError(
view: WebView?,
request: WebResourceRequest?,
error: WebResourceError?
) {
super.onReceivedError(view, request, error)
}
override fun onReceivedHttpError(
view: WebView?,
request: WebResourceRequest?,
errorResponse: WebResourceResponse?
) {
super.onReceivedHttpError(view, request, errorResponse)
}
override fun onReceivedSslError(
view: WebView?,
handler: SslErrorHandler?,
error: SslError?
) {
super.onReceivedSslError(view, handler, error)
}
}
Settings:
webViewer.webViewClient = webViewClient
webViewer.settings.javaScriptEnabled = true
webViewer.isHorizontalScrollBarEnabled = true
webViewer.settings.mixedContentMode = WebSettings.MIXED_CONTENT_COMPATIBILITY_MODE

Try to handle SSL errors within onReceivedSslError to proceed with the certificate
override fun onReceivedSslError(
view: WebView?,
handler: SslErrorHandler?,
error: SslError?
) =
if (handler != null) {
handler.proceed()
} else {
super.onReceivedSslError(view, handler, error)
}

Related

Trying to load params through webViewClient but getting error from mnemonics not defined

Here is my code and it's working in demo project but not in my project. I am trying to add these parameters through webView Client but it is showing from mnemonics not found.
fun sendTrx(c:Context, from_address: String, fromMnemonics: String, amount: String, toAddress: String) {
mycontext=c
var webvw = WebView(mycontext)
webvw.addJavascriptInterface(this, "Android")
webvw.settings.javaScriptEnabled = true
webvw.settings.domStorageEnabled=true
webvw.webViewClient = object : WebViewClient() {
override fun shouldOverrideUrlLoading(
view: WebView?,
request: WebResourceRequest?
): Boolean {
getCustomHeaders()?.let { view!!.loadUrl(request!!.url.toString(), it) };
return true;
}
}
webvw.loadUrl("file:///android_asset/send.html")
val amtChanged = amount.toDouble() * 1000000000000
val amtTobeTransferred = BigDecimal(amtChanged).toBigInteger()
webvw.webViewClient = object : WebViewClient() {
override fun onPageStarted(view: WebView?, url: String?, favicon: Bitmap?) {
super.onPageStarted(view, url, favicon)
webvw.loadUrl("javascript:from_address(\"$from_address\")")
webvw.loadUrl("javascript:fromMnemonics(\"$fromMnemonics\")")
webvw.loadUrl("javascript:amtTobeTransferred(\"$$amtTobeTransferred\")")
webvw.loadUrl("javascript:toAddress(\"$toAddress\")")
// webvw.loadUrl("javascript:toAddress(\"$toAddress\")")
}
}
check in your javascript code that you have field/ method named "fromMnemonics" or not

WebView Issue when using thumbnail page

Some time page with poster thumbnail throws null pointer exception in web view[Andoid].
I have already tried this code.
`lateinit var webView: WebView
webView = view.findViewById(R.id.webView) as WebView
webView.settings.javaScriptEnabled = true
webView.isHorizontalScrollBarEnabled = false
webView.postDelayed({ webView.loadUrl(url) }, 100)
webView.webViewClient = object : WebViewClient() {
override fun onPageStarted(view: WebView?, url: String?, favicon: Bitmap?) {
super.onPageStarted(view, url, favicon)
progressLayout.visibility = View.VISIBLE
}
override fun onPageFinished(view: WebView, url: String) {
// do your stuff here
progressLayout.visibility = View.INVISIBLE
homeScreenImage.visibility = View.GONE
}
}`
Please try this if it works
you can use web chrome client and override default video poster and load default bitmap in case of loading fails
webView.webChromeClient = object : WebChromeClient() {
override fun getDefaultVideoPoster(): Bitmap? {
val result = super.getDefaultVideoPoster()
return result ?: Bitmap.createBitmap(1, 1, Bitmap.Config.RGB_565)
}
override fun onProgressChanged(view: WebView?, newProgress: Int) {
super.onProgressChanged(view, newProgress)
}
}

Android WebView not showing content at Api 20

I have a WebView in my app. It works properly but at Api 20, WebView does not show the content.
I checked the logs and see these errors
I/chromium: [INFO:CONSOLE(7)] "The key "shrink-to-fit" is not recognized and ignored.", source: https://...
I/chromium: [INFO:CONSOLE(43)] "Uncaught SyntaxError: Block-scoped declarations (let, const, function, class) not yet supported outside strict mode", source: https://... (43)
I overviewed some answers and they generally suggest to use
webView.settings.useWideViewPort = true
webView.settings.loadWithOverviewMode = true
I have already implement these settings but still same error happens. WebView shows noting
Here is my WebView Settings
/**
* Initialize the WebView
*/
#SuppressLint("SetJavaScriptEnabled")
private fun initWebView() {
webView.webViewClient = object : WebViewClient() {
#RequiresApi(Build.VERSION_CODES.LOLLIPOP)
override fun shouldOverrideUrlLoading(view: WebView, request: WebResourceRequest): Boolean {
return super.shouldOverrideUrlLoading(view, request)
}
override fun onPageStarted(
view: WebView, url: String, favicon: Bitmap?) {
showProgressDialog()
}
override fun onPageFinished(view: WebView, url: String) {
hideProgressDialog()
}
#RequiresApi(api = Build.VERSION_CODES.M)
override fun onReceivedError(view: WebView, request: WebResourceRequest, error: WebResourceError) {
// Your code to do
hideProgressDialog()
}
override fun onReceivedError(view: WebView, errorCode: Int, description: String, failingUrl: String) {
// Handle the error
hideProgressDialog()
}
override fun onReceivedSslError(view: WebView, handler: SslErrorHandler?, error: SslError) {
// ignore ssl error
if (handler != null) {
handler.proceed()
} else {
super.onReceivedSslError(view, null, error)
}
}
}
webView.isHorizontalScrollBarEnabled = false
webView.settings.javaScriptEnabled = true
webView.settings.useWideViewPort = true
webView.setInitialScale(1)
webView.settings.loadWithOverviewMode = true
context?.let { webView.setBackgroundColor(ContextCompat.getColor(it, R.color.colorDarkBlue)) }
}
/**
* Load url
*/
private fun loadPage(url: String) {
webView.loadUrl(url)
}
Someone have a idea? I will be appreciate for any help

Solve too many redirect in android webview

I created an android WebView and open my website who server with https and authentication redirection anyway this work successfully in all of modern browsers like opera, chrome, Firefox , edge and eth but in android WebView i got 'too many redirect' error
By the way when I set WebView cache mode to none, this error had gone, but i need the cache mode,
Any body can help me?
Use this code to initialize webview and set url, it is work fine with me with all Android versions
#SuppressLint("SetJavaScriptEnabled")
private fun initWebView() {
webView.settings.javaScriptEnabled = true
webView.settings.loadsImagesAutomatically = true
webView.scrollBarStyle = View.SCROLLBARS_INSIDE_OVERLAY
webView.setLayerType(View.LAYER_TYPE_SOFTWARE, null)
}
private fun webViewListener() {
webView.webViewClient = object : WebViewClient() {
override fun onPageStarted(view: WebView?, url: String?, favicon: Bitmap?) {
super.onPageStarted(view, url, favicon)
Log.d(TAG, url)
}
override fun onReceivedError(view: WebView, request: WebResourceRequest,
error: WebResourceError) {
super.onReceivedError(view, request, error)
//Error load url
}
override fun shouldOverrideUrlLoading(view: WebView?, request: WebResourceRequest?): Boolean {
//Loading url
view?.loadUrl(url)
return true
}
}
}
Add this line in Manifest File
<application
...
android:usesCleartextTraffic="true">
You can read more about usesCleartextTraffic

Handle Multiple Tab in Android WebView

I am making an Android browser app, I want to handle link click that has target='_blank', which will open in a new tab in normal browsers.
There is a method call onCreateWindow in WebChromeClient which is triggering when a _blank link clicked. But my question is how can I get the link URL? following code is just returning the current URL
override fun onCreateWindow(view: WebView?, isDialog: Boolean, isUserGesture: Boolean, resultMsg: Message?): Boolean {
Toast.makeText(context, view?.url, Toast.LENGTH_LONG).show()
return super.onCreateWindow(view, isDialog, isUserGesture, resultMsg)
}
Finally, I found a way to capture the link URL.
#SuppressLint("SetJavaScriptEnabled")
override fun onCreateWindow(view: WebView?, isDialog: Boolean, isUserGesture: Boolean, resultMsg: Message?): Boolean {
val newWebView = WebView(context)
addView(context, newWebView)
val transport = resultMsg?.obj as WebView.WebViewTransport
transport.webView = newWebView
val settings = newWebView.getSettings()
settings.javaScriptEnabled = true
settings.javaScriptCanOpenWindowsAutomatically = true
settings.setSupportMultipleWindows(true)
settings.useWideViewPort = false
newWebView.webViewClient = object : WebViewClient() {
override fun onPageFinished(view: WebView?, url: String?) {
super.onPageFinished(view, url)
}
override fun onPageStarted(view: WebView?, url: String?, favicon: Bitmap?) {
Toast.makeText(context, url, Toast.LENGTH_LONG).show()
super.onPageStarted(view, url, favicon)
}
}
resultMsg.sendToTarget()
return true
}
By creating a new web and adding it to the WebViewTransport, you can add a new WebViewClient to that new WebView then its easy to capture that URL from onPageStarted method.

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