Android WebView and loadData

Question

It s possible to use following method for content s setting of a web-view loadData String data  String mimeType  String encoding   How to handle the problem with unknown encoding of html data    Is there a list of encodings    I know from my college that in my case html comes from DB and is encoded with latin-1  I try to set encoding parameter to latin-1  to ISO-8859-1   iso-8859-1  but still have problem with displaying of special signs like              I ll be very thankful for any advice

User · Answer

String strWebData  html          Your html string     WebView webDetail  WebView  findViewById R id webView1     WebSettings websetting   webDetail getSettings      websetting setDefaultTextEncodingName  utf-8      webDetail loadData strWebData   text html  charset utf-8   null

User · Answer

The safest way to load htmlContent in a Web view is to    use base64 encoding  official recommendation  specify UFT-8 for html content type  i e    text html  charset utf-8  instead of  text html   personal advice     Base64 encoding  is an official recommendation that has been written again  already present in Javadoc  in the latest 01 2019 bug in Chrominium  present in WebView M72  72 0 3626 76     https   bugs chromium org p chromium issues detail id 929083  Official statement from Chromium team    Recommended fix  Our team recommends you encode data with Base64  We ve provided examples for how to do so    API docs  https   developer android com reference android webkit WebView html loadData java lang String  20java lang String  20java lang String  Video talk  https   youtu be HGZYtDZhOEQ t 598  jump to time stamp 9 58    This fix is backwards compatible  it works on earlier WebView versions   and should also be future-proof  you won t hit future compatibility problems with respect to content encoding     Code sample   webView loadData      Base64 encodeToString          htmlContent getBytes StandardCharsets UTF 8           Base64 DEFAULT      encode in Base64 encoded       text html  charset utf-8      utf-8 html content  personal recommendation       base64       always use Base64 encoded data  NEVER PUT  utf-8  here  using base64 or not   This is wrong

User · Answer

As I understand it  loadData   simply generates a data  URL with the data provide it   Read the javadocs for loadData        If the value of the encoding parameter is  base64   then the data must be encoded as base64  Otherwise  the data must use ASCII encoding for octets inside the range of safe URL characters and use the standard  xx hex encoding of URLs for octets outside that range  For example                     should be replaced by  23   25   27   3f respectively       The  data  scheme URL formed by this method uses the default US-ASCII charset  If you need need to set a different charset  you should form a  data  scheme URL which explicitly specifies a charset parameter in the mediatype portion of the URL and call loadUrl String  instead  Note that the charset obtained from the mediatype portion of a data URL always overrides that specified in the HTML or XML document itself    Therefore  you should either use US-ASCII and escape any special characters yourself  or just encode everything using Base64  The following should work  assuming you use UTF-8  I haven t tested this with latin1    String data            the html data String base64   android util Base64 encodeToString data getBytes  UTF-8    android util Base64 DEFAULT   webView loadData base64   text html  charset utf-8    base64

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use this   String   customHtml  text               wb loadDataWithBaseURL null customHtml  text html    UTF-8   null

User · Answer

WebView loadData   is not working properly at all  What I had to do was   String header     lt  xml version   1 0   encoding   UTF-8     gt    myWebView loadData header myHtmlString   text html    UTF-8      I think in your case you should replace UTF-8 with latin1 or ISO-8859-1 both in header and in WebView loadData     And  to give a full answer  here is the official list of encodings  http   www iana org assignments character-sets  I update my answer to be more inclusive   To use WebView loadData   with non latin1 encodings you have to encode html content  Previous example was not correctly working in Android 4   so I have modified it to look as follows   WebSettings settings   myWebView getSettings    settings setDefaultTextEncodingName  utf-8    if  Build VERSION SDK INT  gt   Build VERSION CODES FROYO        String base64   Base64 encodeToString htmlString getBytes    Base64 DEFAULT       myWebView loadData base64   text html  charset utf-8    base64      else       String header     lt  xml version   1 0   encoding   UTF-8     gt        myWebView loadData header   htmlString   text html  charset UTF-8   null        But later I have switched to WebView loadDataWithBaseURL   and the code became very clean and not depending on Android version   WebSettings settings   myWebView getSettings    settings setDefaultTextEncodingName  utf-8    myWebView loadDataWithBaseURL null  htmlString   text html    utf-8   null     For some reason these functions have completely different implementation

User · Answer

the answers above doesn t work in my case  You need to specify utf-8 in meta tag   lt html gt       lt head gt           lt meta http-equiv  Content-Type  content  text html  charset utf-8  gt       lt  head gt       lt body gt           lt  -- you content goes here -- gt       lt  body gt   lt  html gt

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webview loadDataWithBaseURL null  text   text html    UTF-8   null

User · Answer

myWebView loadData myHtmlString   text html  charset UTF-8   null     This works flawlessly  especially on Android 4 0  which apparently ignores character encoding inside HTML   Tested on 2 3 and 4 0 3   In fact  I have no idea about what other values besides  base64  does the last parameter take  Some Google examples put null in there

User · Answer

I have this problem  but   String content     lt html gt  lt head gt  lt meta http-equiv   content-type   content   text html  charset utf-8     gt  lt  head gt  lt body gt    content    mydata     lt  body gt  lt  html gt    WebView1 loadData content   text html    UTF-8      not work in all devices  And I merge some methods   String content             lt  xml version   1 0   encoding   UTF-8     gt             lt html gt  lt head gt             lt meta http-equiv   content-type   content   text html  charset utf-8     gt             lt  head gt  lt body gt     content    myContent     lt  body gt  lt  html gt     WebView WebView1    WebView  findViewById R id webView1   WebView1 loadData content   text html  charset utf-8    UTF-8      It works

[android] Android. WebView and loadData

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