Android webView - javascript code is not getting called

Question

I try to load this javascript in my webview:

@SuppressLint("ClickableViewAccessibility")
@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_fullscreen);

    website = "https://www.blizz-z.de";
    myWebView = findViewById(R.id.blizzView);

    WebSettings settings = blizzView.getSettings();
    settings.setJavaScriptEnabled(true);

    myWebView.setWebViewClient(new WebViewClient() {

        @Override
        // Notify the host application that a page has finished loading.
        public void onPageFinished(WebView view, String url)
        {
            myWebView.loadUrl(
                    "javascript:(function() {" +
                        "setInterval(function() {" +
                            + "jQuery('#myInput').css('background', '#'+(Math.random()*0xFFFFFF<<0).toString(16));"
                        + "}, 1000);"
                    + "});"
            );
        }
    }

    ...

}

But it is not getting executed. If I execute the script in my desktop browser, then it works. It changes the background color of my search bar on my website just for test purposes.

Is setInterval not supported in webView?

Update:

I tried it with the function js from @mohkamfer's answer:

@SuppressLint("ClickableViewAccessibility")
@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_fullscreen);

    website = "https://www.blizz-z.de";
    blizzView = findViewById(R.id.blizzView);

    WebSettings settings = blizzView.getSettings();
    settings.setJavaScriptEnabled(true);

    myWebView.setWebViewClient(new WebViewClient() {

        @Override
        // Notify the host application that a page has finished loading.
        public void onPageFinished(WebView view, String url)
        {
            js(myWebView, "(function() {" +
                        "setInterval(function() {" +
                            + "jQuery('#myInput').css('background', '#'+(Math.random()*0xFFFFFF<<0).toString(16));"
                        + "}, 1000);"
                    + "});"
            );
        }
    }

    ...

}

public void js(WebView view, String code)
{
    String javascriptCode = "javascript:" + code;
    if (Build.VERSION.SDK_INT >= 19) {
        view.evaluateJavascript(javascriptCode, new ValueCallback<String>() {

            @Override
            public void onReceiveValue(String response) {
                Log.i("debug_log", response);
            }
        });
    } else {
        view.loadUrl(javascriptCode);
    }
}

But it makes no difference.

Khang .NT · Accepted Answer · 2020-08-24 06:15:00Z

1

Are you deploying on API 19 or higher? If so you'll have to use WebView#evalulateJavascript instead of WebView#loadUrl

I always use this method to simplify and quicken things a bit

public void js(String code) {
    if (Build.VERSION.SDK_INT >= 19) {
        this.evaluateJavascript(code, new ValueCallback<String>() {
            @Override
            public void onReceiveValue(String response) {
            }
        });
    } else {
        this.loadUrl("javascript:" + code);
    }
}

edited Aug 24, 2020 at 6:15

Khang .NT

1,6086 gold badges25 silver badges48 bronze badges

answered Jul 24, 2019 at 11:46

mohkamfer

4413 silver badges14 bronze badges

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

6 Comments

Black Over a year ago

I get cannot resolve Method "evaluteJavascript"

mohkamfer Over a year ago

Are you sure you referenced it from myWebView instance instead of this?

Black Over a year ago

I replaced this with "myWebView` now I get "Cannot resolve symbol ValueCallback"

Black Over a year ago

I had to import android.webkit.ValueCallback

Black Over a year ago

Nevermind, I figured out how to use your code, I had to add another parameter "WebView view" to your function. I tried it but the javascript code is not called.

|

Black · Accepted Answer · 2019-07-24 12:57:00Z

0

I figured it out... I just had to call the code with jQuery(document).ready(function() {. The code was executed but did not changed anything because it was executed before the DOM was ready...

Solution:

@SuppressLint("ClickableViewAccessibility")
@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_fullscreen);

    website = "https://www.blizz-z.de";
    myWebView = findViewById(R.id.blizzView);

    WebSettings settings = blizzView.getSettings();
    settings.setJavaScriptEnabled(true);

    myWebView.setWebViewClient(new WebViewClient() {

        @Override
        // Notify the host application that a page has finished loading.
        public void onPageFinished(WebView view, String url)
        {
            js(myWebView, "jQuery(document).ready(function() {" +
                        "setInterval(function() {" +
                            + "jQuery('#myInput').css('background', '#'+(Math.random()*0xFFFFFF<<0).toString(16));"
                        + "}, 1000);"
                    + "});"
            );
        }
    }

    ...

}

public void js(WebView view, String code)
{
    String javascriptCode = "javascript:" + code;
    if (Build.VERSION.SDK_INT >= 19) {
        view.evaluateJavascript(javascriptCode, new ValueCallback<String>() {

            @Override
            public void onReceiveValue(String response) {
                Log.i("debug_log", response);
            }
        });
    } else {
        view.loadUrl(javascriptCode);
    }
}

Credits to @mohkamfer for contributing the js function.

edited Jul 24, 2019 at 12:57

answered Jul 24, 2019 at 12:54

Black

20.9k47 gold badges188 silver badges300 bronze badges

2 Comments

mohkamfer Over a year ago

That's great, as a rule of thumb always print/log a statement to make sure everything is working!

Black Over a year ago

@mohkamfer, yes I was setting a breakpoint and debugged the app. But I thought the JS is not working at all because nothing happened even though your js function was entered and evaluateJavascript was called.

Collectives™ on Stack Overflow

Android webView - javascript code is not getting called

2 Answers 2

6 Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

6 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related