I want to show a button when android webview reach bottom

Question

I have added a webview inside a dialog. I want to enable the dialog positive button when the user has scrolled the webview to the bottom, so that I can assume that the user has read the user agreement.

Answer 1

You can solve it via Javascript. In the webpage, add the JS code to detect if the user has scrolled to the bottom like this (credits to this post )

$(window).scroll(function() {
    if($(window).scrollTop() + $(window).height() == $(document).height()) {
        Android.onUserScrolledToBottom()
    }
});

Then in your Android app, create a Javascript Interface class

class MyJavascriptInterface {
    TermsAndCondActivity termsAndCondActivity;

    MyJavascriptInterface(TermsAndCondActivity termsAndCondActivity) {
        this.termsAndCondActivity = termsAndCondActivity;
    }

    @JavascriptInterface
    public void onUserScrolledToBottom() {
        termsAndCondActivity.onUserScrolledToBottom();
    }
}

Finally in your TermsAndCondActivity, setup the WebView in the onCreate like this

myWebView = view.findViewById(R.id.my_web_view);
myWebView.setWebViewClient(new WebViewClient());
myWebView.getSettings().setJavaScriptEnabled(true);
myWebView.addJavascriptInterface(new MyJavascriptInterface(this), "Android");

And add the following method

void onUserScrolledToBottom() {
    button.setEnabled(true);
}

As an example I've used an activity since you didn't specify the dialog's code, but you should be able to adapt the code easily.

Answer 2

Thanks for your answers. I have achieved this using onScrollChange() method.

   webView.setOnScrollChangeListener(new View.OnScrollChangeListener() {
                    @Override
                    public void onScrollChange(View view, int i, int i1, int i2, int i3) {

                        if(i1>=webView.getContentHeight()){
                            dialog.getButton(AlertDialog.BUTTON_POSITIVE).setVisibility(View.VISIBLE);

                        }else {
                            dialog.getButton(AlertDialog.BUTTON_POSITIVE).setVisibility(GONE);
                        }
                    }
                });