WebView.draw(android.graphics.Canvas) won't draw HTML5 canvas to android.graphics.Canvas -

hey i'm trying draw webview bitmap following way:

customwebview webview = (customwebview) findviewbyid(r.id.chart_webview_renderer);  string capturepathstring = environment.getexternalstoragedirectory().getpath() + "/temp/ms_" + system.currenttimemillis() + ".png";  bitmap bm = bitmap.createbitmap(webview.getmeasuredwidth(), webview.getmeasuredheight(), bitmap.config.argb_8888);  canvas bigcanvas = new canvas(bm); paint paint = new paint(); int iheight = bm.getheight(); bigcanvas.drawbitmap(bm, 0, iheight, paint); webview.draw(bigcanvas);  if (bm != null) {     try {         outputstream fout = null;         file file = new file(capturepathstring);         fout = new fileoutputstream(file);          bm.compress(bitmap.compressformat.png, 50, fout);         fout.close();         fout.flush();         bm.recycle();     } catch (exception e) {         e.printstacktrace();     } } 

this works fine on tablets have available testing here (galaxy tab 2 , 3). results in white bitmap of correct size on sony xperia z , samsung galaxy s2.

the webpage trying draw bitmap contains html5 canvas , when add normal html it, draw html bitmap fine.

the webview set invisible behind views, although have tried making visible , on top of views produced no different results.

i wasn't able solve issue original method used. added following javascript fix html: https://code.google.com/p/todataurl-png-js/ allow use of

canvas.todataurl()  

which returns base64 encoded png image. used

webview.addjavascriptinterface 

to allow javascript send base64 encoded image java, saved on device.

a rough example of did this:

// after initializing webview: javascriptinterface jsinterface = new javascriptinterface(); webview.getsettings().setjavascriptenabled(true); webview.addjavascriptinterface(jsinterface, "android");  // class used javascript interface saving image file public class javascriptinterface {     @javascriptinterface     public void canvastoimage(string base64imagedata){         string capturepathstring = environment.getexternalstoragedirectory().getpath() + "/temp/ms_" + system.currenttimemillis() + ".png";          try{             file file = new file(capturepathstring);             file.getparentfile().mkdirs();             fileoutputstream fos = new fileoutputstream(file);             byte[] decodedstring = android.util.base64.decode(base64imagedata, android.util.base64.default);             fos.write(decodedstring);              fos.flush();             fos.close();         }catch(exception e){             e.printstacktrace();         }     } }  // in javascript looks function canvastoimage(){     var dataurl = canvas.todataurl();      window.android.canvastoimage(dataurl.replace("data:image/png;base64,", "")); } 

it isn't clean i'd hope be, works on devices here now!