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

A

23

174

I'm struggling to create a WebView with transparent background.

webView.setBackgroundColor(0x00FFFFFF);
webView.setBackgroundDrawable(myDrawable);

Then I load a html page with

<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 ?

Amytal answered 15/2, 2011 at 11:39 Comment(1)

I'm sorry to say, but for my problem no solution listed here worked... :=( thx anyways.. the webpage always used a white background... – Valerio 6/9, 2012 at 5:53

A

31

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

Amytal answered 1/3, 2011 at 8:28 Comment(0)

N

319

This worked for me,

mWebView.setBackgroundColor(Color.TRANSPARENT);

Noreennorene answered 5/5, 2011 at 14:47 Comment(7)

Have you really tested on os 2.2 ? – Amytal 8/5, 2011 at 9:13

I found that this has to be called AFTER loading the url or data. – Detriment 21/7, 2011 at 18:7

it doesn't work in android 3.x if you are using android:hardwareAccelerated="true" – Goodly 28/7, 2011 at 18:46

Note that on ICS(4.0.3), in addition to above comments; I had to disable "Settings -> Developer Options -> Force GPU Rendering" to get transparency to work with API level 10. – Candlemaker 28/8, 2012 at 21:57

Well, HW accel dont handle alpha, and a bunch of other nice canvas related features. It makes me sad ... – Lecherous 25/9, 2012 at 12:14

ACtually I don't understand why this answer gets so many up votes. webView.setBackgroundColor(0x00000000); is exactly the same as webView.setBackgroundColor(0x00FFFFFF); the alpha value is 0x00. – Amytal 26/9, 2012 at 22:26

Some code for different devices always yields randomly different result. Android or "Randroid"? – Sycamore 18/3, 2015 at 18:46

G

133

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

Gianna answered 20/8, 2012 at 14:24 Comment(7)

It Works as long as the Webview is not scrollable. – Kailyard 16/11, 2012 at 13:14

I needed set background color after force software rendering on samsung S3 – Scorekeeper 16/5, 2013 at 10:34

webView.setBackgroundColor(Color.argb(1, 0, 0, 0)); if you want no background flickering on scroll – Chiarra 12/7, 2013 at 20:22

@Trent I tried your method and if fixed the flicker problem on Jelly Bean, but now it displays a black background on Gingerbread. Any other suggestion? – Faison 28/8, 2013 at 23:33

Only true way for make webview background transparent. Great solution! – Truant 28/2, 2014 at 13:43

@Trent getting the same black background issue on 4.0.4 - did you get a solution for this? – Selfmortification 23/10, 2014 at 19:59

This disables hardware acceleration for the webview ! ! This was not obvious to me (blame on me for not looking it up before using :D), and the last sentence of the answer leaves the opposite impression. This actually affects a lot of things, videos, UI transformations, scrolling, canvas etc. A possible workaround https://mcmap.net/q/144533/-transparent-webview-not-working-on-android-v4-0 – Hypothecate 9/1, 2016 at 0:59

D

38

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("<!DOCTYPE html><head> <meta http-equiv=\"Content-Type\" " +
      "content=\"text/html; charset=utf-8\"> </head><body><div style=\"background-color: rgba(10,10,10,0.5); " +
      "padding: 20px; height: 260px; border-radius: 8px;\"> $$$ Content Goes Here ! $$$ </div> </body></html>");

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. enter image description here

Demotic answered 1/6, 2012 at 7:14 Comment(0)

A

31

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

Amytal answered 1/3, 2011 at 8:28 Comment(0)

C

22

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 >= 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 >= 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

Culler answered 10/12, 2012 at 17:16 Comment(1)

this works for me: android:hardwareAccelerated="false" BODY, HTML {background: transparent} – Usable 4/4, 2013 at 7:39

C

16

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

    <body style="display: flex; background-color:transparent">some content</body>

Activity

    WebView wv = (WebView) findViewById(R.id.webView);
    wv.setBackgroundColor(0);
    wv.setLayerType(View.LAYER_TYPE_SOFTWARE, null);
    wv.loadUrl("file:///android_asset/myview.html");

Chokebore answered 29/6, 2014 at 11:32 Comment(1)

It's mentioned in the question. But this seems to be a nice resume of what you have to do if you want it to work on all android versions. – Amytal 30/6, 2014 at 10:10

V

9

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 >= 11) {
        webview.setLayerType(WebView.LAYER_TYPE_SOFTWARE, null);
    }

above code use full for me.

Vortumnus answered 28/12, 2012 at 9:27 Comment(1)

I don't recommend you setLayerType to LAYER_TYPE_SOFTWARE. It drastically decreases performance especially when scrolling. – Have 27/1, 2014 at 16:53

D

8

Try webView.setBackgroundColor(0);

Daggerboard answered 28/2, 2011 at 19:50 Comment(1)

There is no difference between webView.setBackgroundColor(0x00FFFFFF); and webView.setBackgroundColor(0x00); Both are supposed to be transparent color. – Amytal 1/3, 2011 at 8:26

C

7

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);

Coniology answered 6/12, 2011 at 10:54 Comment(3)

This works on Honeycomb, but unfortunately not on ICS. Damn. But if you use it, it is more easier to specify it in the layout file using the "android:layerType" property as this will also work well on older releases where the tag will simply be ignored. – Hummingbird 1/3, 2012 at 21:10

What's working even on ICS is to deactivate hardware acceleration for the whole activity using android:hardwareAccelerated="false" in the AndroidManifest for the activity element. – Hummingbird 1/3, 2012 at 22:22

There is unnecessarily to create Paint object. v.setLayerType(LAYER_TYPE_SOFTWARE, null); also will work. – Gurney 12/3, 2012 at 12:24

T

6

Use this

WebView myWebView = (WebView) findViewById(R.id.my_web);

myWebView.setBackgroundColor(0);

Tale answered 2/9, 2012 at 4:34 Comment(1)

0 (0x00000000) = Color.TRANSPARENT see developer.android.com/reference/android/graphics/… – Phlogopite 2/8, 2015 at 0:3

C

6

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

Charmeuse answered 1/11, 2012 at 6:0 Comment(0)

F

5

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.

Fenrir answered 13/2, 2013 at 6:30 Comment(0)

I

3

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

Invalid answered 21/2, 2014 at 14:35 Comment(0)

V

3

This didn't work,

android:background="@android:color/transparent"

Setting the webview background color as worked

webView.setBackgroundColor(0)

Additionally, I set window background drawable as transparent

Vincenty answered 28/9, 2020 at 11:20 Comment(0)

B

2

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..

Brandie answered 6/2, 2012 at 8:53 Comment(0)

T

2

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"
```

Trustless answered 28/10, 2013 at 19:8 Comment(0)

C

1

Try

webView.setBackgroundColor(Color.parseColor("#EDEDED"));

Cristophercristy answered 29/10, 2012 at 11:46 Comment(0)

H

0

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);
    }
}

Horodko answered 5/7, 2013 at 9:13 Comment(1)

I tested this on a Galaxy Nexus and flickering remained, unfortunately. – Have 27/1, 2014 at 16:59

F

0

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);
        }
    });

Faux answered 3/11, 2014 at 10:17 Comment(0)

F

0

Try out:

myWebView.setAlpha(0.2f);

Flowered answered 18/4, 2018 at 19:11 Comment(0)

L

0

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.

Luhey answered 19/10, 2018 at 8:9 Comment(0)

W

0

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:

<layout >

    <data>

        <import type="com.tdk.sekini.R" />


    </data>

       <WebView
            ...
            app:setBackground="@{R.color.grey_10_transparent}"/>

</layout>

Resources

<color name="grey_10_transparent">#11e6e6e6</color>

Whitehouse answered 27/1, 2020 at 18:10 Comment(0)

V

-3

myWebView.setAlpha(0);

is the best answer. It works!

Vaporimeter answered 13/2, 2019 at 4:12 Comment(1)

Please explain why as well. – Emendate 13/2, 2019 at 4:26

The most important thing was not mentioned.

So the full solution would be:

HTML

Activity

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