save webview html file

mkvidyashankar · May 26, 2011

is it possible to save webview html file for offline reading

Erel · Aug 29, 2011

You can save any string to a file by calling File.WriteString.

mkvidyashankar · Aug 30, 2011

Error in saving html file

B4X:

Sub Process_Globals
Dim hc As HttpClient
Dim req As HttpRequest
End Sub

Sub Globals
   'These global variables will be redeclared each time the activity is created.
   'These variables can only be accessed from this module.
   Dim WebView1 As WebView
   
End Sub

Sub Activity_Create(FirstTime As Boolean)
   Activity.LoadLayout("layoutMain")
   '   add the B4A javascript namespace to the WebView
   'WebInterface.addJSInterface(WebView1, "B4A")
   '   now load a web page
   WebView1.LoadUrl("http://www.b4x.com/")
End Sub

Sub Activity_Resume
End Sub

Sub Activity_Pause (UserClosed As Boolean)
End Sub

Sub WebView1_PageFinished (Url As String)
   getremotemessages("http://www.b4x.com/")
End Sub

Sub GetRemoteMessages(postUrl As String)               
   'Set up an http request connection
     req.InitializeGet(PostUrl)
   hc.Execute(req, 1)                                                
End Sub

Sub hc_ResponseSuccess (Response As HttpResponse, TaskId As Int)         'We got connection and data !!

    Dim resultString As String
    resultString = Response.GetString("UTF8")   'This holds the returned data 
    WebView1.LoadHtml(resultString)
   response.Release
   File.WriteList(File.DirDefaultExternal,"trial.html",resultstring)         
            
End Sub
Sub hc_ResponseError (Response As HttpResponse, Reason As String, StatusCode As Int, TaskId As Int)      'No connection :-(
    Log("Error connecting: " & Reason & " " & StatusCode)
    If Response <> Null Then
        Log(Response.GetString("UTF8"))
      ProgressDialogHide
        Response.Release
    End If
End Sub

I tried your code with save option, but not able to retrieve and save, please help:sign0085:

Erel · Aug 30, 2011

I've added [ code ] tags to your post. It makes it much easier to read code.

Which part doesn't work?
You should use File.WriteString not File.WriteList.

knarf123 · Dec 27, 2011

error when executing scripts

warwound said:
Here's an alternative that should do as the OP originally asked.

First you need to use my JSInterface library.
Now you can execute javascript in your WebView from your B4A code and your WebView can also now call a B4A Sub.

B4X:

'Activity module Sub Process_Globals 'These global variables will be declared once when the application starts. 'These variables can be accessed from all modules. End Sub Sub Globals 'These global variables will be redeclared each time the activity is created. 'These variables can only be accessed from this module. Dim myInterface As JSInterface Dim WebView1 As WebView End Sub Sub Activity_Create(FirstTime As Boolean) Activity.LoadLayout("layoutMain") WebView1.Width=100%x WebView1.Height=100%y ' add the B4A javascript interface to the WebView myInterface.addJSInterface(WebView1, "B4A") ' now load a web page WebView1.LoadUrl("http://www.b4x.com/android/help/jsinterface.html") End Sub Sub Activity_Resume End Sub Sub Activity_Pause (UserClosed As Boolean) End Sub Sub WebView1_PageFinished (Url As String) ' Now that the web page has loaded we can get the page content as a String Dim jsStatement As String jsStatement="B4A.CallSub('processHTML', document.documentElement.outerHTML)" Log("PageFinished: "&jsStatement) myInterface.execJS(WebView1, jsStatement) End Sub Sub processHTML(html As String) ' This is the Sub that we'll get the web page to send it's HTML content to ' Log may truncate a large page so you'll not see all of the HTML in the log but the 'html' String should still contain all of the web page HTML Log("processHTML: "&html) End Sub

You can see that the code waits for the PageFinished event before requesting that the web page sends it's HTML content to the B4A Sub 'processHTML'.

This method has an advantage over the previously posted examples - that is when a web page had been dynamically created and it's content is not static.
The user may have submitted a form for example and be viewing a (dynamically generated) web page that cannot be requested using HttpClient.

Martin.

Martin,
I tried your example but I am getting the following error:
"Compiling code. Error
Error parsing program.
Error description: Unknown type: jsinterface
Are you missing a library reference?
Occurred on line: 12
Dim myInterface As JSInterface"

I added the reference files to C:\Basic4android\Libraries

Do I also need to add it in B4A?
I am new to B4.
Regards,
Frank

Erel · Dec 27, 2011

Yes, you need to select it in the Lib tab (right side of the IDE).

knarf123 · Dec 28, 2011

Worked

Thanks that worked. I saw it was also one of the tips

peacemaker · Mar 4, 2012

I use 5 pcs of WebViews, all of them set as:

WvE(i).addJavascriptInterface(wv(i), "B4A")

After:

jsStatement="B4A.CallSub('processHTML', document.documentElement.outerHTML)"
WvE(i).executeJavascript(wv(i), jsStatement)

the application is silently closed :-((((

warwound · Mar 4, 2012

The syntax you are using in your CallSub statement is the syntax for my older JSInterface library.

The newer WebViewExtras requires an extra parameter callUIThread:

CallSub(subName As String, callUIThread As boolean, parameter1 As String)

The callUIThread parameter is an important update - it's not available with JSInterface.

Does the Sub called by your javascript modify your activity UI?
If the answer is yes then you need to pass boolean true as callUIThread otherwise you can pass false.
If you pass false and then the Sub tries to modify your activity UI you will get an exception.

So you need to modify your code to:

B4X:

Dim callUIThread As Boolean
callUIThread=??
jsStatement="B4A.CallSub('processHTML', callUIThread, document.documentElement.outerHTML)"
WvE(i).executeJavascript(wv(i), jsStatement)

Choosing a value for callUIThread based on whether the javascript causes your B4A activity to make any changes to the user interface.

Generally, if the javascript is not going to receive a return value from B4A you can use True even if the UI is not modified.

Martin.

peacemaker · Mar 4, 2012

No help, with True or False.
with
jsStatement="B4A.CallSub('processHTML', True\False, document.documentElement.outerHTML)" - also

warwound · Mar 4, 2012

Oops...!

The javascript statement String should be:

B4X:

"B4A.CallSub('processHTML', true, document.documentElement.outerHTML)"

OR

B4X:

"B4A.CallSub('processHTML', false, document.documentElement.outerHTML)"

Javascript uses all lower case for true and false.

If that still fails then add the WebChromeClient to your WebView and look at the Log for any relevant error messages:

B4X:

MyWebViewExtras.addWebChromeClient(WvE(i))

If your app force closes then look at the unfiltered Log for errors.

Martin.

peacemaker · Mar 4, 2012

Strange, but does not help. Adding WebChromeClient also.

B4X:

Sub SaveHTML (i As Int)
    '    Now that the web page has loaded we can get the page content as a String
    Dim jsStatement As String
    jsStatement="B4A.CallSub('processHTML', false, document.documentElement.outerHTML)"
    
    WvE(i).executeJavascript(wv(i), jsStatement)
End Sub

Sub processHTML(html As String) As String
   
    Log("processHTML: "&html)
   Return html
End Sub

warwound · Mar 4, 2012

First thing i see in your log is a problem with the WebViewXtended library:

Could not find method android.webkit.WebView.canZoomIn, referenced from method thalmy.webviewxtended.xtender.canZoomIn
VFY: unable to resolve virtual method 412: Landroid/webkit/WebView;.canZoomIn ()Z
VFY: replacing opcode 0x6e at 0x0000
VFY: dead code 0x0003-0008 in Lthalmy/webviewxtended/xtender;.canZoomIn (Landroid/webkit/WebViewLjava/lang/Boolean;
Could not find method android.webkit.WebView.canZoomOut, referenced from method thalmy.webviewxtended.xtender.canZoomOut
VFY: unable to resolve virtual method 413: Landroid/webkit/WebView;.canZoomOut ()Z
VFY: replacing opcode 0x6e at 0x0000
VFY: dead code 0x0003-0008 in Lthalmy/webviewxtended/xtender;.canZoomOut (Landroid/webkit/WebViewLjava/lang/Boolean;

The parts of the log that look to be WebViewExtras related make no sense to me:

JNI WARNING: jarray 0x40580f90 points to non-array object (Ljava/lang/String
"WebViewCoreThread" prio=5 tid=11 NATIVE
| group="main" sCount=0 dsCount=0 obj=0x40583d68 self=0x267ab8
| sysTid=12760 nice=0 sched=0/0 cgrp=default handle=2523448
| schedstat=( 509754101 354504239 113 )
at android.webkit.BrowserFrame.stringByEvaluatingJavaScriptFromString(Native Method)
at android.webkit.BrowserFrame.stringByEvaluatingJavaScriptFromString(Native Method)
at android.webkit.BrowserFrame.loadUrl(BrowserFrame.java:246)
at android.webkit.WebViewCore.loadUrl(WebViewCore.java:1570)
at android.webkit.WebViewCore.access$1400(WebViewCore.java:53)
at android.webkit.WebViewCore$EventHub$1.handleMessage(WebViewCore.java:956)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:123)
at android.webkit.WebViewCore$WebCoreThread.run(WebViewCore.java:629)
at java.lang.Thread.run(Thread.java:1019)

Yet a Google for jarray points to non-array object took me to this thread at StackOverflow:

This is a bug with 2.3.x. simulator - Javascript->Java bridge is bugged.

The Google bug specifically uses this demo code. Issue 12987 - android - Javascript to Java Bridge Throws Exception on Android 2.3 - Android - An Open Handset Alliance Project - Google Project Hosting

Go star it so they know to fix it soon.

You can workaround this for now by just using a 2.2 emulator.

Are you running your code on a 2.3 emulator?

Martin.

peacemaker · Mar 4, 2012

warwound said:
Are you running your code on a 2.3 emulator?
Martin.

EXACTLY ! 2.2 emulator works OK !
Thank you very much !
And update the first post with the lib to warn users about this emulator problem, pls.

zeuspower · May 30, 2012

hello from Greece,to all the team here and a big BRAVO to the makers of
B4a !!!

My problem is this:

I want to save the contents of a webview to a string
(i can't use http methods,because the page is not directly accessible,it
needs javascripts to go to the page i want...)

so i make some "games" with the pageFinished and some javascripts
and i go to the desired page but i can't get it as string..

to get the page to a string, i use the following :

B4X:

Dim jsStatement

             jsStatement="B4A.CallSub('processHTML',true, document.documentElement.outerHTML)"

MyWebViewExtras.executeJavascript(WebView1,jsStatement)

---------------
Sub processHTML(html As String)

   Log("processHTML: " & html)
   
   End Sub

it did nothing,until i used the addwebchromeclient method and i discovered
at the log the following error:

ReferenceError: Can't find variable: B4A in undefined (Line: 1)

oh,I forgot,i tried it on both 2.2 and 2.3 emulators...

warwound · May 30, 2012

ReferenceError: Can't find variable: B4A in undefined (Line: 1)

B4A is undefined - you try to execute the javascript B4A.CallSub('processHTML',true, document.documentElement.outerHTML) which causes this error.

Sounds to me as though you have either not used WebViewExtras to add a JavascriptInterface OR you have not used 'B4A' as the interface name.

B4X:

MyWebViewExtras.addJavascriptInterface(WebView1, "B4A")

That will add the JavascriptInterface with the "B4A" interface name and now you should be able to execute B4A.CallSub('processHTML',true, document.documentElement.outerHTML).

Martin.

zeuspower · May 30, 2012

Thanks for the fast responce...It worked !

Gregg Homan · Jan 23, 2014

Hello,

WarWound wrote example code (see below) on 7/11/2011 that demonstrated how to use his library WebViewExtras to save html content via WebView. I am using B4A V3.20 and WebViewExtras V1.40 and I saw no forum posts that suggest that this code fails yet when I execute this example code it fails and I get the following error showing up in the log:

Ignoring event: processhtml. Raised from the wrong thread.

Can anyone suggest what is causing the example code below (per WarWound) to fail?

Thanks,
Gregg

B4X:

'Activity module
Sub Process_Globals
End Sub

Sub Globals
    Dim myInterface As WebViewExtras 'Requires WebViewExtras library which replaced JSInterface Library
    Dim WebView1 As WebView
End Sub

Sub Activity_Create(FirstTime As Boolean)
    Activity.LoadLayout("layoutMain")
    myInterface.addJavascriptInterface(WebView1, "B4A")
    WebView1.LoadUrl("http://www.b4x.com/android/help/jsinterface.html")
End Sub

Sub Activity_Resume
End Sub

Sub Activity_Pause (UserClosed As Boolean)
End Sub

Sub WebView1_PageFinished (Url As String)
    Dim jsStatement As String = "B4A.CallSub('processHTML', document.documentElement.outerHTML)"
    myInterface.executeJavascript(WebView1, jsStatement)
End Sub

Sub processHTML(html As String)
    Log("processHTML: "&html)
End Sub

warwound · Jan 24, 2014

@Gregg Homan

What device are you running this on?
What version of android is that device running?

Martin.

billzhan · Jan 24, 2014

I don't have 3.2,but I think it it something to do with obfuscation. See: http://www.b4x.com/android/forum/threads/android-code-obfuscation.13773/

If you are running with the sample code under Run(obfuscation), the Sub processHTML will be lost. You need to change it to process_HTML(something with _) .

The revised sample code is attached.

warwound · Jan 24, 2014

billzhan said:
I don't have 3.2,but I think it it something to do with obfuscation. See: http://www.b4x.com/android/forum/threads/android-code-obfuscation.13773/

If you are running with the sample code under Run(obfuscation), the Sub processHTML will be lost. You need to change it to process_HTML(something with _) .

But the posted error was:

Ignoring event: processhtml. Raised from the wrong thread.

Martin.

save webview html file

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