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>

score 7 · Answer 1 · answered Mar 28 '13 at 03:14

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 '13 at 03:14

Tushar

8,019
31
38

I think that might be my problem. I will try it now. – user2206969 Mar 28 '13 at 03:33
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. – user2206969 Mar 28 '13 at 03:42
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. – Sujit Oct 03 '20 at 11:52

Han Tran · Answer 2 · 2013-03-28T04:28:47.130

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 '13 at 04:28

answered Mar 28 '13 at 03:51

Han Tran

2,073
4
22
37

Please flesh out your answer. – joce Mar 28 '13 at 04:08
Edited answer, check it :) – Han Tran Mar 28 '13 at 04:30
That you didn't try very hard. – joce Mar 28 '13 at 04:36
Explain WHY you suggest the answer you're suggesting. – joce Mar 28 '13 at 04:36
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? – Han Tran Mar 28 '13 at 04:39
Yours is a mediocre answer as it is. Just so you know. This, by contrast, is a very high quality answer: http://stackoverflow.com/questions/921180/how-can-i-ensure-that-a-division-of-integers-is-always-rounded-up/926806#926806 – joce Mar 28 '13 at 04:43
A simple solution don't need to explain to long like your link, right? Just you think so :) – Han Tran Mar 28 '13 at 04:47

score 0 · Answer 3 · edited Jun 19 '17 at 09:22

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 '17 at 09:22

Sayed Abolfazl Fatemi

3,678
3
36
48

answered Mar 28 '13 at 04:29

hRb

61
2

score 0 · Answer 4 · edited Jun 19 '17 at 10:24

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 '17 at 10:24

Sayed Abolfazl Fatemi

3,678
3
36
48

answered Jan 05 '14 at 14:46

Christoforos

564
3
13

score 0 · Answer 5 · answered Apr 24 '14 at 13:39

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 '14 at 13:39

Naveed Ahmad

6,627
2
58
83

score 0 · Answer 6 · answered Jan 23 '15 at 12:04

0

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

answered Jan 23 '15 at 12:04

Sanjay Kumar

1,135
14
27

score 0 · Answer 7 · edited Dec 31 '15 at 08:20

 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()+"\")"); }
        });

calling javascript function from an android activity

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