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Internet use on the Pi

A lot of people like about it giving inbuilt add blocker the standard form of Chromium  with all the adds or other issues made by  Google for why it should load very fast for  you ,it kind of reminds me of using the older browsers before it became all about the ads which Google made into big thing in the past or present a like.   I think a problem many people have not worked out yet if you want to make a website attractive  you need balance between to much ads and no ads for things to work well but the Pi takes care of this problem out of the bow by it's starting browser being decided to get around the internet speed you loss from to many ads. You can if you prefer easy install Brave I use it a lot of  the system as well seems to work as well as the starter internet browser you get so kind of what you prefer you may prefer Firefox or something else. Tor works well on it as well so if you want to go down more the privacy mode many options exist and will work...
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2015/04/05/Execute-JavaScript-in-Android-without-WebView/



April 16, 2022

The reasons I need do some Javascript code in Andriod based project was because of me running the background thread (in doinbackground part in an Asynctask), I want want to use Webview


Why not WebView


The first problem here is that Webview is heavy which then makes it run slow overall which is bigger problem when you are doing large kind of proejct and you need to add as well a lot of webview related setting which slows things done further when you want to do things like code snippet so my thoughts it’s not worth doing it because of these sort of problems overall.


Second main points I want to make which is UI related webview should be created in a UI thread which will then load Javascript code in the background of the thread then pass the results bac kto the UI it’s workable overall but it’s not safe in my thoughts.


If you can call methods on webview from any other thread than your app UI thread it can cause unexpected results. https://developer.android.com/guide/webapps/migrating#Threads


Last but not final Webview is fragmented after Android 4.4 or level 19 is using Webview based on Chromium style and even oo this is a good thing my mindset is 4.3 so a older version which could give you problems. You should try and code two versions of Webview in related code to just try and make it work. https://www.theengineer.info/2023/02/google-drive-programming-style-and.html


A lot of code should be re-wrote.

JavaScript Brand computer graphic


Luckily, the good people in Mozilla make a project called Rhino. It is typically embedded into Java applications to provide scripting to end users.


How to use Rhino?


Rhino is a open source project, you can get the source code using this command:


git clone https://github.com/mozilla/rhino.git


Of course, you don’t have to get the source code. If you want to use it in your Android


project. Download Rhino first, unzip it, put the js.jar file under libs folder. It is very small, so you don’t need to worry your apk file will be ridiculously large because of this one external jar.


Here is some simple code to execute JavaScript code.


Object[] params = new Object[] { “javaScriptParam” };


// Every Rhino VM begins with the enter()


// This Context is not Android’s Context


Context rhino = Context.enter();


// Turn off optimization to make Rhino Android compatible


rhino.setOptimizationLevel(-1);


try {


Scriptable scope = rhino.initStandardObjects();


// Note the forth argument is 1, which means the JavaScript source has


// been compressed to only one line using something like YUI


rhino.evaluateString(scope, javaScriptCode, “JavaScript”, 1, null);


// Get the functionName defined in JavaScriptCode


Object obj = scope.get(functionNameInJavaScriptCode, scope);


if (obj instanceof Function) {


Function jsFunction = (Function) obj;


// Call the function with params


Object jsResult = jsFunction.call(rhino, scope, scope, params);


// Parse the jsResult object to a String


String result = Context.toString(jsResult);


}


} finally {


Context.exit();


}


As you can see, it is quite easy. You can dig up more in Rhino document.


Proguard & Obfuscation


You can set up Rhino’s proguard setting by adding this following line into your proguard-android.txt file.


-keep class org.mozilla.javascript.** { *; }


When you run the assembleRelease task, with minifyEnabled true of course, you still can see a lot of warning like these:


Warning: org.mozilla.javascript.tools.shell.JSConsole: can’t find referenced class javax.swing.JMenu


Warning: org.mozilla.javascript.tools.shell.JSConsole: can’t find referenced class javax.swing.JMenu


Warning: org.mozilla.javascript.tools.shell.JSConsole: can’t find referenced class javax.swing.JMenu


Warning: org.mozilla.javascript.tools.shell.JSConsole: can’t find referenced class javax.swing.ButtonGroup


Warning: org.mozilla.javascript.tools.shell.JSConsole: can’t find referenced class javax.swing.JScrollPane


Warning: org.mozilla.javascript.tools.shell.JSConsole: can’t find


referenced class java.awt.event.ActionEvent


Warning: org.mozilla.javascript.tools.shell.JSConsole: can’t find referenced class java.awt.event.ActionEvent


Warning: org.mozilla.javascript.tools.shell.JSConsole$1: can’t find referenced class javax.swing.filechooser.FileFilter


Warning: org.mozilla.javascript.tools.shell.JSConsole$2: can’t find referenced class java.awt.event.WindowAdapter


Warning: org.mozilla.javascript.tools.shell.JSConsole$2: can’t find referenced class java.awt.event.WindowEvent


Warning: org.mozilla.javascript.tools.shell.JSConsole$2: can’t find referenced class java.awt.event.WindowEvent


Warning: org.mozilla.javascript.xml.impl.xmlbeans.LogicalEquality: can’t find referenced class org.apache.xmlbeans.XmlCursor


Warning: org.mozilla.javascript.xml.impl.xmlbeans.LogicalEquality: can’t find referenced class org.apache.xmlbeans.XmlCursor


Warning: org.mozilla.javascript.xml.impl.xmlbeans.LogicalEquality: can’t find referenced class org.apache.xmlbeans.XmlCursor


Luckily, evan with these warnings, the app runs fine. You can ignore them(that’s what I do), or adding this line inot your proguard-android.txt file.


-dontwarn org.mozilla.javascript.**


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