using javascript in android webview

Question

I'm trying to start an activity from a javascript interface in my webview. The example shows a toast. How could i call a class instead of a toast?

public class JavaScriptInterface {
Context mContext;

/** Instantiate the interface and set the context */
JavaScriptInterface(Context c) {
    mContext = c;
}

/** Show a toast from the web page */
public void showToast(String toast) {
    Toast.makeText(mContext, toast, Toast.LENGTH_SHORT).show();
}
}

this for the html page.

<input type="button" value="Say hello" onClick="showAndroidToast('Hello Android!')" />

<script type="text/javascript">
function showAndroidToast(toast) {
    Android.showToast(toast);
}

I'm not experienced enough to answer but have you read this: developer.android.com/guide/webapps/… — JaredMcAteer
– JaredMcAteer, Commented May 6, 2012 at 18:08
Ok I just didn't see anywhere where you enabled the javascript in the webview and though it was relevant. — JaredMcAteer
– JaredMcAteer, Commented May 6, 2012 at 18:13
u didnt get my question , i want to call an intent instead of a toast . i already made that toasts example working. thx anyway — Common
– Common, Commented May 6, 2012 at 18:50
I want to do it without any webview . just internally is it possible. — Sagar Nayak
– Sagar Nayak, Commented Apr 17, 2016 at 9:09

Vishal Dalve · Accepted Answer · 2017-09-25 07:50:58Z

73

You have to first register the JavaScriptInterface on your webview. JavaScriptInterFace can be a inner class as shown below. This class will have a function that you can call from html page( via javaScript ) and inside this function you can write code to change activity.

Here is the working solution for you:

public class JavascriptInterfaceActivity extends Activity {
    /** Called when the activity is first created. */


    WebView wv;

    JavaScriptInterface JSInterface;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        wv = (WebView)findViewById(R.id.webView1);

        wv.getSettings().setJavaScriptEnabled(true);
        // register class containing methods to be exposed to JavaScript

        JSInterface = new JavaScriptInterface(this);
        wv.addJavascriptInterface(JSInterface, "JSInterface"); 

        wv.loadUrl("file:///android_asset/myPage.html");

    }


    public class JavaScriptInterface {
        Context mContext;

        /** Instantiate the interface and set the context */
        JavaScriptInterface(Context c) {
            mContext = c;
        }

        @android.webkit.JavascriptInterface
        public void changeActivity()
        {
            Intent i = new Intent(JavascriptInterfaceActivity.this, nextActivity.class);
            startActivity(i);
            finish();
        }
    }
}

Here is the html page

<html>
<head>
<script type="text/javascript">
function displaymessage()
{
JSInterface.changeActivity();
}
</script>
</head>

<body>
<form>
<input type="button" value="Click me!" onclick="displaymessage()" />
</form>
</body>
</html>

Hope this helps...

edited Sep 25, 2017 at 7:50

Vishal Dalve

3243 silver badges16 bronze badges

answered May 7, 2012 at 11:15

Akshay

1,1371 gold badge10 silver badges12 bronze badges

Sign up to request clarification or add additional context in comments.

9 Comments

Common Over a year ago

Thank you my friend . it almost helped me to solve my problem .

Android Killer Over a year ago

@Common i should take the above html code in separate html file ?

Tony_craft Over a year ago

This is useful to call android functions from a javascript, but there is any way to call javascript functions from android code?

Mohini Over a year ago

what is the location of this html file ?

Alison Over a year ago

I have one question, where to put the HTML page ?

|

Collins Abitekaniza · Accepted Answer · 2017-06-13 08:16:27Z

18

You also need to add the @android.webkit.JavascriptInterface annotation on top of your changeActivity method in your android code, should you run on Android 4.2 or higher. See this link for more.

edited Jun 13, 2017 at 8:16

Collins Abitekaniza

4,5882 gold badges30 silver badges43 bronze badges

answered Feb 19, 2014 at 20:07

goseib

7373 gold badges12 silver badges24 bronze badges

Collectives™ on Stack Overflow

using javascript in android webview

2 Answers 2

9 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

9 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related