Android WebView style background-color transparent ignored on android 2 2

Question

I m struggling to create a WebView with transparent background   webView setBackgroundColor 0x00FFFFFF   webView setBackgroundDrawable myDrawable     Then I load a html page with    lt body style  background-color transparent         The background color of the WebView is transparent but as soon as the page is loaded  it s overwritten by a black background from the html page  This only happens on android 2 2  it works on android 2 1   So is there something to add in the html page code to make it really transparent

User · Answer

I was trying to put a transparent HTML overlay over my GL view but it has always black flickering which covers my GL view. After several days trying to get rid of this flickering I found this workaround which is acceptable for me (but a shame for android).

The problem is that I need hardware acceleration for my nice CSS animations and so webView.setLayerType(View.LAYER_TYPE_SOFTWARE, null); is not an option for me.

The trick was to put a second (empty) WebView between my GL view and the HTML overlay. This dummyWebView I told to render in SW mode, and now my HTML overlays renders smooth in HW and no more black flickering.

I don't know if this works on other devices than My Acer Iconia A700, but I hope I could help someone with this.

public class MyActivity extends Activity {

    @Override
    protected void onCreate(Bundle icicle) {
        super.onCreate(icicle);

        RelativeLayout layout = new RelativeLayout(getApplication());
        setContentView(layout);

        MyGlView glView = new MyGlView(this);

        RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.MATCH_PARENT);

        dummyWebView = new WebView(this);
        dummyWebView.setLayoutParams(params);
        dummyWebView.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
        dummyWebView.loadData("", "text/plain", "utf8");
        dummyWebView.setBackgroundColor(0x00000000);

        webView = new WebView(this);
        webView.setLayoutParams(params);
        webView.loadUrl("http://10.0.21.254:5984/ui/index.html");
        webView.setBackgroundColor(0x00000000);


        layout.addView(glView);
        layout.addView(dummyWebView);
        layout.addView(webView);
    }
}

User · Answer

You can user BindingAdapter like this   Java   BindingAdapter  setBackground   public static void setBackground WebView view  ColorRes int resId            view setBackgroundColor view getContext   getResources   getColor resId            view setLayerType WebView LAYER TYPE SOFTWARE  null       XML    lt layout  gt        lt data gt            lt import type  com tdk sekini R    gt         lt  data gt           lt WebView                             app setBackground    R color grey 10 transparent    gt    lt  layout gt    Resources   lt color name  grey 10 transparent  gt  11e6e6e6 lt  color gt

User · Answer

This didn t work  android background  quot  android color transparent quot   Setting the webview background color as worked webView setBackgroundColor 0   Additionally  I set window background drawable as transparent

User · Answer

below code works fine Android 3 0  but when you try this code below android 3 0 then your app forcefully closed   webView setLayerType WebView LAYER TYPE SOFTWARE  null     You try below code on your less then API 11   webview setBackgroundColor Color parseColor   919191       Or  you can also try below code which works on all API fine       webview setBackgroundColor Color parseColor   919191         if  Build VERSION SDK INT  gt   11            webview setLayerType WebView LAYER TYPE SOFTWARE  null           above code use full for me

User · Answer

I had the same issue with 2 2 and also in 2 3  I solved the problem by giving the alpa value in html not in android  I tried many things and what I found out is setBackgroundColor    color doesnt work with alpha value  webView setBackgroundColor Color argb 128  0  0  0    will not work   so here is my solution  worked for me         String webData   StringHelper addSlashes   lt  DOCTYPE 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 div style   background-color  rgba 10 10 10 0 5              padding  20px  height  260px  border-radius  8px    gt      Content Goes Here        lt  div gt   lt  body gt  lt  html gt       And in Java       webView    WebView  findViewById R id webview       webView setBackgroundColor 0       webView loadData webData   text html    UTF-8      And here is the Output screenshot below

User · Answer

set the bg after loading the html from quick tests it seems loading the html resets the bg color   this is for 2 3    if you re loading the html from data you already got  just doing a  postDelayed in which you just set the bg to for example transparent  is enough

User · Answer

Try out   myWebView setAlpha 0 2f

User · Answer

This worked for me  try setting the background color after the data is loaded  for that setWebViewClient on your webview object like       webView setWebViewClient new WebViewClient              Override         public void onPageFinished WebView view  String url                        super onPageFinished view  url               webView setBackgroundColor Color BLACK

User · Answer

myWebView setAlpha 0     is the best answer  It works

User · Answer

Try webView setBackgroundColor Color parseColor   EDEDED

User · Answer

If webview is scrollable    Add this to the Manifest   android hardwareAccelerated  false     OR   Add the following to WebView in the layout   android background   android color transparent  android layerType  software   Add the following to the parents scroll view   android layerType  software

User · Answer

After trying everything given above  I found it doesn t matter either you specify webView setBackgroundColor Color TRANSPARENT  before or after loadUrl    loadData    The thing that matters is you should explicitly declare android hardwareAccelerated  false  in the manifest    Tested on IceCream Sandwich

User · Answer

The most important thing was not mentioned  The html must have a body tag with background-color set to transparent  So the full solution would be   HTML      lt body style  quot display  flex  background-color transparent quot  gt some content lt  body gt   Activity     WebView wv    WebView  findViewById R id webView       wv setBackgroundColor 0       wv setLayerType View LAYER TYPE SOFTWARE  null       wv loadUrl  quot file    android asset myview html quot

User · Answer

Just use these lines        webView loadDataWithBaseURL null  Hello    text html    utf-8   null   webView setBackgroundColor 0x00000000     And remember a point that Always set background color after loading data in webview

User · Answer

Actually it s a bug and nobody found a workaround so far  An issue has been created  The bug is still here in honeycomb   Please star it if you think it s important   http   code google com p android issues detail id 14749

User · Answer

Try  webView setBackgroundColor 0

User · Answer

Following code work for me  though i have multiple webviews and scrolling between them is bit sluggish   v setBackgroundColor Color TRANSPARENT   Paint p   new Paint    v setLayerType LAYER TYPE SOFTWARE  p

User · Answer

This is how you do it   First make your project base on 11  but in AndroidManifest set minSdkVersion to 8  android hardwareAccelerated  false  is unnecessary  and it s incompatible with 8  wv setBackgroundColor 0x00000000   if  Build VERSION SDK INT  gt   11  wv setLayerType WebView LAYER TYPE SOFTWARE  null    this wv setWebViewClient new WebViewClient          Override     public void onPageFinished WebView view  String url                wv setBackgroundColor 0x00000000           if  Build VERSION SDK INT  gt   11  wv setLayerType WebView LAYER TYPE SOFTWARE  null               For safety put this in your style   BODY  HTML  background  transparent    worked for me on 2 2 and 4

User · Answer

Use this   WebView myWebView    WebView  findViewById R id my web    myWebView setBackgroundColor 0

User · Answer

webView setBackgroundColor 0x00000000   webView setLayerType WebView LAYER TYPE SOFTWARE  null     this will definitely work    set background in XML with Editbackground   Now that background will be shown

User · Answer

If nothing helps  then most probably you have fixed sized webView  change the width and height to wrap content or match parent  it should work  That worked for me when I tried to load a Gif

User · Answer

At the bottom of this earlier mentioned issue there is an solution  It s a combination of 2 solutions  webView setBackgroundColor Color TRANSPARENT   webView setLayerType WebView LAYER TYPE SOFTWARE  null    When adding this code to the WebViewer after  loading the url  it works  API 11    It even works when hardeware acceleration is ON

User · Answer

This worked for me   mWebView setBackgroundColor Color TRANSPARENT

[android] Android WebView style background-color:transparent ignored on android 2.2

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