Calling javascript function from the android activity

Question

I am using the following code in the main activity , its giving the function display() is not defined

public class cordovaExample extends DroidGap {
    Context mcontext;
    private novel n;
    private Server s;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        new Thread(new Server(this)).start();
        try {
            Thread.sleep(500);
        } catch (InterruptedException e) { }
        new Thread(new Client()).start();

        super.init();

        n = new novel(this, appView); 
        s = new Server(this,appView);

        appView.getSettings().setJavaScriptEnabled(true);
        appView.addJavascriptInterface(n, "novel");
        appView.addJavascriptInterface(s, "Server");

        super.loadUrl("file:///android_asset/www/index.html");
        super.loadUrl("javascript:display()");
    }
}

At the last line it giving the error display() is not defined

function display() {
    alert("abc");
}

Above code shows the display function which is I am using in the html file

Any type of help will be appreciated

Zathrus Writer · Accepted Answer · 2012-09-20T14:24:48.460

6

It's a bad idea to make Cordova load JavaScript on page load. This should be handled by your local JavaScript. Try to call your display() function like this in the HTML page itself:

<script>
    function display()
    {


        alert("abc");


    }

    window.onload = function() {
        display();
    }
</script>

If you need to call a JavaScript from within Cordova at any later point, it is possible to do so this way:

sendJavascript("display();");

To access this method from other classes, you will need to access your main activity. The easy-but-perhaps-unsafe method is to create a static variable in your main Activity that will hold the activity itself. Example:

public class MyActivity extends DroidGap {
    public static MyActivity activity;

    public void onCreate(Bundle savedInstanceState) {
        activity = this;
    }
}

Then, from anywhere in your classes, do:

MyActivity.activity.sendJavascript('display();');

edited Sep 20 '12 at 14:24

answered Sep 20 '12 at 13:54

Zathrus Writer

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thanx sir for answering , if i want to call the javascript method from other method which is not the activity , then?? – akshay1728 Sep 20 '12 at 14:11
see the updated answer... btw, Plugins have always access to `sendJavascript()` function – Zathrus Writer Sep 20 '12 at 14:24
@ZathrusWriter hi, I'm overriding `shouldOverrideUrlLoading` method of the `CordovaWebViewClient` class. From there `sendJavascript("alert('1234');");` doen't seem to work. any ideas? Posted question [here](http://stackoverflow.com/questions/17156827/cordova-send-message-to-javascript) – arod Jun 18 '13 at 20:08
@arod sorry, I'm outta PhoneGap for about half a year now, so I can't really answer that. But good luck anyway! – Zathrus Writer Jun 19 '13 at 09:00

score 1 · Answer 2 · answered May 25 '14 at 04:53

From Cordova 2.6 you can override onMessage in your CordovaActivity (DroidGap), you have to capture the message "onPageFinished", then you can call any function declared on the document:

@Override
public Object onMessage(String id, Object data) {
    if("onPageFinished".equals(id)) {
        sendJavascript("display('abc');");
    }
    return super.onMessage(id, data);
}

And in the HTML:

<script>
    function display(arg) {
        alert(arg);
    }
</script>

Other option is to call it in the onResume() function of the CordovaActivity:

@Override
public void onResume() {
    super.onResume();
    sendJavascript("display('abc');");
}

Calling javascript function from the android activity

2 Answers2

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