Android Web Console Uncaught ReferenceError

Question

I am calling a native android function via java script loaded in a webview but is not working Here is what i have done with WebView

paintView = (WebView) findViewById(R.id.webView1);
WebSettings Websettings = paintView.getSettings();
Websettings.setBuiltInZoomControls(true);
Websettings.setSupportZoom(true);
Websettings.setJavaScriptEnabled(true);
Websettings.setBuiltInZoomControls(true);
Websettings.setRenderPriority(RenderPriority.HIGH);
paintView.getSettings().setPluginState(PluginState.ON);
paintView.setWebChromeClient(new WebChromeClient());
final MyJavaScriptInterface myJavaScriptInterface = new MyJavaScriptInterface(this);
paintView.loadUrl("file:///android_asset/index_jQueryMobile.html");

and here is the android method

@JavascriptInterface
public void byteToImage(String base64img, String ImageName) throws IOException
{
    byte[] pdfAsBytes = Base64.decode(base64img.toString(), 0);
    File file = new File(Environment.getExternalStorageDirectory()+"/AndroPaint");
    if(!file.exists()) {
        file.mkdirs();
    }
    File filePath = new File(Environment.getExternalStorageDirectory()+"/AndroPaint/"+ImageName+".png");
    FileOutputStream os = new FileOutputStream(filePath, true);
    os.write(pdfAsBytes);
    os.flush();
    os.close();
}

and here is the JS function

function getImageBytes()
{
    var canvas = document.getElementById('canvas');
    var imageName = document.getElementById('imgName');
    var imgData= canvas.toDataURL();
    activity.byteToImage(imgData,imageName);
}

here is the exception

01-04 10:48:50.409: E/Web Console(15681): Uncaught ReferenceError: activity is not defined:72

Answer 1

You made a connection interface MyJavaScriptInterface, but you forgot to attach it to the WebView:

paintView.addJavascriptInterface(new MyJavaScriptInterface(this), "activity");

That is why you are getting activity is not defined error. activity object cannot be found by JS engine.

Here is a small tutorial on that