calling javascript function from an android activity

Question

I wan to call a javascript function from an android activity but it doesn't seem to work. I have used the android webview function webview.loadUrl("javascript:function()"); This is my android code:

package com.example.web;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.webkit.WebView;

public class MainActivity extends Activity {

    WebView webview;
    int i=30;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        webview = (WebView)findViewById(R.id.webView1);
        webview.getSettings().setJavaScriptEnabled(true);
        webview.loadUrl("file:///android_asset/index.html");
        webview.loadUrl("javascript:change(i)");

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }

}

This is my html code:

 <html>
<body>
<div id="texta">text</div>
<script>

function change(num){
document.getElementById("texta").innerHTML=num;
}

</script>

</body>
</html>

Tushar · Accepted Answer · 2013-03-28 03:14:30Z

7

It's likely your page isn't fully loaded by the time you're trying to execute the javascript. Can you try:

webView.setWebViewClient(new WebViewClient() {

   public void onPageFinished(WebView view, String url) {
        view.loadUrl("javascript:change(i)");
    }
});

answered Mar 28, 2013 at 3:14

Tushar

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3 Comments

user2206969 Over a year ago

I think that might be my problem. I will try it now.

user2206969 Over a year ago

I tried using the function without passing any argument and manually set the value in the javascript section and it worked fine. But when i pass the variable i to the function it doesn't not work.

Sujit Over a year ago

This worked for me. Thanks! Tho I think the function will be called everytime the page loads, even for a different URL, say I click on a search result, the function will get called again when the page loads whether it exists or not. To fix that you could use if or switch statements to call the javascript function depending on the url string.

Han Tran · Accepted Answer · 2013-03-28 04:28:47Z

0

Try:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    webview = (WebView)findViewById(R.id.webView1);
    webview.getSettings().setJavaScriptEnabled(true);
    webview.loadUrl("file:///android_asset/index.html");
    webview.loadUrl("javascript:change("+String.valueOf(i)+")");

}

edited Mar 28, 2013 at 4:28

answered Mar 28, 2013 at 3:51

Han Tran

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7 Comments

joce Over a year ago

Please flesh out your answer.

Han Tran Over a year ago

Edited answer, check it :)

joce Over a year ago

That you didn't try very hard.

joce Over a year ago

Explain WHY you suggest the answer you're suggesting.

Han Tran Over a year ago

You don't see any change from the code at the question and the my answer or NOT? A programer can easy see the different and WHY of this answer. Any other problem?

|

Naveed Ahmad · Accepted Answer · 2014-04-24 13:39:54Z

0

What is "i", If "i" is a number then Specify the Number, if "i" is a character then kindly enclose it in double Quotes, you are calling a method of some arguments, so kindly correct your mistake.

answered Apr 24, 2014 at 13:39

Naveed Ahmad

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Comments

Sanjay Kumar · Accepted Answer · 2015-01-23 12:04:01Z

0

try webview.loadUrl("javascript:change(\""+i"\")");

answered Jan 23, 2015 at 12:04

Sanjay Kumar

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Comments

Tunaki · Accepted Answer · 2015-12-31 08:20:53Z

 protected void onCreate(Bundle savedInstanceState) 
 {
   super.onCreate(savedInstanceState);
   setContentView(R.layout.activity_main);
   final Activity MyActivity = this;
   text=(EditText)findViewById(R.id.textValue);
   Show=(Button)findViewById(R.id.textButton);
   webView= (WebView) findViewById(R.id.webView);
   getWindow().setFeatureInt(Window.FEATURE_PROGRESS,
                                    Window.PROGRESS_VISIBILITY_ON);
   webView.setWebChromeClient(new WebChromeClient() {
   public void onProgressChanged(WebView view, int progress) {

   MyActivity .setTitle("Loading...");
     MyActivity .setProgress(progress * 100);

     if (progress == 100)
     MyActivity .setTitle("Android Dhina");
    }
   });
     webView.setWebViewClient(new WebViewClient());
     webView.addJavascriptInterface(new WebAppInterface(this), "Android");

     webView.getSettings().setJavaScriptEnabled(true);
     webView.loadUrl("file:///android_asset/web.html");

     Show.setOnClickListener(new OnClickListener()
      {
       @Override
       public void onClick(View v) 
       {
         webView.loadUrl("javascript:callFromAndroidActivity
                          (\""+text.getText().toString()+"\")"); }
        });

Sayed Abolfazl Fatemi · Accepted Answer · 2017-06-19 09:22:34Z

0

Try it:

String URL = "file:///android_asset/filename.html";
webviewBrowser=(WebView)findViewById(R.id.webview);
webview.getSettings().setJavaScriptEnabled(true);
webview.setWebViewClient(new WebViewClient(webview.loadUrl(URL));

edited Jun 19, 2017 at 9:22

Sayed Abolfazl Fatemi

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answered Mar 28, 2013 at 4:29

hRb

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Comments

Sayed Abolfazl Fatemi · Accepted Answer · 2017-06-19 10:24:14Z

0

Try to change this :

webview.loadUrl("javascript:change(i)");

to this

webview.loadUrl("javascript:change(" + i +")");

the way you have write it the "i" is not the variable "i" from your java code but just a String named "i".

edited Jun 19, 2017 at 10:24

Sayed Abolfazl Fatemi

3,9313 gold badges40 silver badges51 bronze badges

answered Jan 5, 2014 at 14:46

Christoforos

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