Android WebView loadUrl JavaScript not working API <=18 (but works in API >=19)

Question

QUESTION:
What do I have to do to make webView.loadUrl(javaScript) work in API 18 or lower (in comparison to API 19 or higher)?

DESCRIPTION OF PROBLEM:
I am using WebView to make a chat.

First I load the HTML like so: webView.loadUrl(url);
Then I use loadUrl again to send in the chat message like so: webView.loadUrl(javaScript);

This works perfectly fine in API >=19 but does not work in API <=18.

Chat messages do still get received from other devices but the other devices do not get a single message from the device with API 18 or lower. The exact same code is used.

I've searched a lot and will continue to search. If you have the answer, any idea that I could test or could redirect me to relevant information please do share. Thank you in advance.

EDIT:
The JavaScript tag in the string is set to lower case (with the same problem): webView.loadUrl("javascript:" + javaScriptFunction);

Name · Accepted Answer · 2015-06-23 09:16:50Z

3

SOLUTION

I found the problem which was that the (encoded) message parameter sent in the JavaScript function had a line break [ \n ] in it. Removing that using the split function msg.split("\n"); made it work.

answered Jun 23, 2015 at 9:16

Name

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ThinkDeep Over a year ago

Is that realy what helps you? WebView wv = new WebView(mContext); WebSettings settings = wv.getSettings(); settings.setJavaScriptEnabled(true); JavaBridgeToJS bridgeToJS = new JavaBridgeToJS(); wv.addJavascriptInterface(bridgeToJS, "javaCallback"); wv.loadUrl("javascript: "var result=foo(); window.javaCallback.result(result)"); while it's working just fine on API > 18, the callback is not called on 18 :( and there is no line break.

Alex Forcier · Accepted Answer · 2015-06-18 17:17:41Z

1

I can't be sure this is what's causing your problem, but try using

webView.loadUrl("javascript:" + theJavaScriptCode);

with lowercase "javascript:".

API 19+ doesn't care about the case of the JavaScript protocol in loadUrl (though you can use evaluateJavascript() instead anyway in API 19+), but API 18 and down doesn't recognize it unless it's written in lower case.

answered Jun 18, 2015 at 17:17

Alex Forcier

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Name Over a year ago

I do have the "javascript:" tag in lower case so that's not it. Thank you though for sharing this information. Do you have any other suggestions? This really confuses me especially when I search for similar problems and find that people have problem making it work API >= 19 instead of API <= 18 as in my case.

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