Webview does not load javascript to get content

Question

I want to get all text in body tag of a url but it doesn't work. I have searched many but i could not find anything. I have also added android.permission.INTERNET also.

so what is the problem?

This is my code:

public class Activity_Main  extends Activity {

@SuppressLint("JavascriptInterface")
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    final WebView webView = (WebView) findViewById(R.id.webView);

    webView.getSettings().setJavaScriptEnabled(true);
    webView.getSettings().setDomStorageEnabled(true);

    final TextView contentView = (TextView) findViewById(R.id.contentView);

    class MyJavaScriptInterface
    {
        private TextView contentView;

        public MyJavaScriptInterface(TextView aContentView)
        {
            contentView = aContentView;
        }

        @SuppressWarnings("unused")

        public void processContent(String aContent)
        {
            final String content = aContent;
            contentView.setText(content);
        }
    }

    webView.getSettings().setJavaScriptEnabled(true);
    webView.addJavascriptInterface(new MyJavaScriptInterface(contentView), "INTERFACE");
    webView.setWebViewClient(new WebViewClient() {
        @Override
        public void onPageFinished(WebView view, String url)
        {
            webView.loadUrl("javascript:window.INTERFACE.processContent(document.getElementsByTagName('body')[0].innerText);");
        }
    });

    webView.loadUrl("https://stackoverflow.com");
  }
}

What should processContent do? There may be a problem with that function. — Ali Sheikhpour, Nov 26 '19 at 11:03
is `processContent` a function in your html page or in Android codes? — Ali Sheikhpour, Nov 26 '19 at 11:16
my code is based on https://stackoverflow.com/questions/9579772/android-get-text-out-of-webview — mohammad noori, Nov 26 '19 at 11:27

Damodhar · Accepted Answer · 2019-11-26T16:32:35.827

update @JavascriptInterface for your interface function and check

class MyJavaScriptInterface
    {
        private TextView contentView;

        public MyJavaScriptInterface(TextView aContentView)
        {
            contentView = aContentView;
        }

        @JavascriptInterface
        public void processContent(String aContent)
        {
            final String content = aContent;
            contentView.setText(content);
        }
    }

and there is another way to do this is this for above KITKAT

 webView.evaluateJavascript("alert('pass here some ...')", new ValueCallback<String>() {
       @Override
       public void onReceiveValue(String s) {

        }
    });

this is update solution for executing js in android

full code is here

final WebView webView = (WebView) findViewById(R.id.webView);

    webView.getSettings().setJavaScriptEnabled(true);
    webView.getSettings().setDomStorageEnabled(true);

    final TextView contentView = (TextView) findViewById(R.id.contentView);

    class MyJavaScriptInterface
    {
        private TextView contentView;

        public MyJavaScriptInterface(TextView aContentView)
        {
            contentView = aContentView;
        }

        @JavascriptInterface
        public void processContent(String aContent)
        {
            final String content = aContent;
            contentView.setText(content);
        }
    }

    webView.getSettings().setJavaScriptEnabled(true);
    webView.addJavascriptInterface(new MyJavaScriptInterface(contentView), "INTERFACE");
    webView.setWebViewClient(new WebViewClient() {
        @Override
        public void onPageFinished(WebView view, String url)
        {
            super.onPageFinished(view,url);


            if (Build.VERSION.SDK_INT>=Build.VERSION_CODES.KITKAT) {
                webView.evaluateJavascript("document.getElementsByTagName('body')[0].innerText", new ValueCallback<String>() {
                    @Override
                    public void onReceiveValue(String s) {
                        contentView.setText(s);
                    }
                });
            }
            else {
                webView.loadUrl("javascript:window.INTERFACE.processContent(document.getElementsByTagName('body')[0].innerText)");

            }


                       }
    });

    webView.loadUrl("https://stackoverflow.com");

it returns null again – mohammad noori Nov 26 '19 at 15:01 — mohammad noori, Nov 26 '19 at 15:01

score 0 · Answer 2 · answered Nov 26 '19 at 11:28

To call a JavaScript function from Android you don't need to add interface prefix:

webView.loadUrl("javascript:processContent(document.getElementsByTagName('body')[0].innerText);");

Note: You must implement the called javascript function in your HTML page. So If you are calling a third party website in your webview, you have only access to the current existing functions in that page.

e.g https://stackoverflow.com has no javascript function named INTERFACE.processContent!

On the contrary when you want to call and Android method from javascript then you need that prefix:

<script>INTERFACE.myAndroidMethod()</script>

Finally if you want to proccess the HTML content of a thirdparty webpage you can not extract the content using a Webview and JavaScript function (that not exists in that page) but you need Android codes to load the webpage content without the WebView mediation.

Webview does not load javascript to get content

2 Answers2