Passing array from js to android

Question

Hi I have this activity code:

public class WebActivity extends ActionBarActivity {

    TextView number;

    WebView mWebView;
    CountDownTimer mTimer;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_web);


        number = (TextView) findViewById(R.id.number);
        mTimer=new CountDownTimer(10000, 1000) {
            String[] myArray={"javascript:document.getElementById(\"utente\").value=\""+LoginActivity.username+"\"; document.getElementById(\"j_password\").value=\""+LoginActivity.password+"\"; document.querySelector(\"input[type=submit]\").click();","javascript:document.getElementById(\"menu-servizialunno:_idJsp14\").click();"};


            int currentIndex=0;
            public void onTick(long millisUntilFinished) {

                number.setText("seconds remaining: " + millisUntilFinished / 1000 + " " + (currentIndex + 1) + "/" + (myArray.length + 1));
            }
            //code comment start
            // i think this part could be written better
            // but it works!!
            public void onFinish() {
                if (currentIndex<myArray.length) {
                    number.setText("done!");
                    mWebView.loadUrl(myArray[currentIndex]);
                    currentIndex++;
                    mTimer.start();
                } else{
                    mTimer.cancel();

                }

            }
            //code comment end
        };

        mTimer.start();
        mWebView = (WebView) findViewById(R.id.webview);
        mWebView.getSettings().setJavaScriptEnabled(true);
        mWebView.setWebViewClient(new WebSliderWebViewClient() {
            @Override
            public void onPageFinished(WebView view, String url) {
                super.onPageFinished(mWebView, url);
                Toast.makeText(getApplicationContext(), "Done!", Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
                Toast.makeText(getApplicationContext(), "Oh no! " + description, Toast.LENGTH_SHORT).show();

            }
        });
        mWebView.loadUrl("http://www.ss16374.scuolanext.info");



    }

and this js function:

function voti( showSubject, showData, showVote ){
    var votitotali = []
    document.getElementById("menu-servizialunno:_idJsp14").click();
    setTimeout(function(){
        elems = document.querySelectorAll("td, legend");
        for(var i = 0; i < elems.length; i++){
            curText = elems[i].innerHTML;
            if( elems[i].tagName == "LEGEND" && showSubject ){
                votitotali += [curText]
                //console.log( curText );
            }else if( elems[i].innerHTML.indexOf("Voto") != -1 && showVote ){
                votitotali += [curText.replace(/.*\(([0-9\.]+)\)/,"$1")]
                //console.log( curText.replace(/.*\(([0-9\.]+)\)/,"$1") );
            }else if( /\d{2}\/\d{2}\/\d{4}/.test(elems[i].innerHTML) && showData ){
                votitotali += [curText.replace(/.*(\d{2}\/\d{2}\/\d{4}).*/,"$1")]
                //console.log( curText.replace(/.*(\d{2}\/\d{2}\/\d{4}).*/,"$1") );
            }
        }
        document.getElementsByClassName("btl-modal-closeButton")[0].click()
    },3000);
    return votitotali
}

Can I store the votitotali array in my android app? Because I need to get some informations from a site and I have to print them on a textView in the app, but I really do not know how to do this using webview...

Answer 1

That's actually easy. You need to inject a Java object which has a method receiving an array:

class MyReceiver {
    @JavascriptInterface
    public void receive(String[] input) {
        // input is your data!
    }
}

// At the very beginning
mWebView.addJavascriptInterface(new MyReceiver(), "receiver");
// ...

Then if you call it like that in your JavaScript code:

receiver.receive(voti( ... ));

You will get the array inside MyReceiver.receive.

Note that non-string array elements (e.g. numbers) will not be converted into strings, and will be replaced by nulls instead.