I am building an Android application in Android studio with Java. I want to use Speech to text and Text to speech and some Machine Learning based python programs that I had already written.
Is it possible to do this? What is the technology stack that I need to accomplish this?
I came across various solutions like using sl4A, Jython, QPython and running the python code on the server.I have also gone through the following but I haven't found a solution yet
Execute python script from android App in Java
How to execute Python script from Java code in Android
Execute python script from android App in Java
Please explain with an example. As an example if I want to use the following python code (Speech to Text conversion using Google Speech recognition API) to run in my android app:
import speech_recognition as sr
r = sr.Recognizer()
with sr.Microphone() as src:
print("speak....")
audio = r.listen(src, 2)
print("over")
try:
print("you said: "+r.recognize_google(audio))
except:
print("cannot recognize")
What steps am I supposed to follow? What is the best way to achieve it?
Thank you in advance.
EDIT 1: Can it be achieved using azure services?
I've been using JEP as a bridge between java and python, I've never actually tried this on android apps, only webapps. (in the FAQS of the project they state that it could work)
private RunOutputModel run(RunInputModel model, String path) throws Exception {
RunOutputModel retVal = new RunOutputModel();
try (SharedInterpreter jep = new SharedInterpreter()) {
jep.eval("import sys");
jep.eval("sys.path.append('" + path + "')");
jep.eval("import master_main");
jep.set("well", model.getWell());
jep.set("startDate", model.getStartDate());
jep.set("endDate", model.getEndDate());
//other vars
jep.eval("objClass = master_main.master()");
jep.eval("x = objClass.main(path, well, startDate, endDate,/*vars*/)");
Object result1 = jep.getValue("x");
//manager result
}
} catch (Exception e) {
retVal.setStatus(e.getMessage());
Utils.log("error", e.getMessage(), path);
}
return retVal;
}
And here's python:
class master:
def __init__(self):
self.SETVARIABLES = ''
def main(self, path, well, startDate, endDate):
#stuff
By searching I've found this, they even have project examples of mixed source code app (both python and java).
Related
I am extremely new the Android app development and Stack Overflow. I am trying to recreate traceroute in an Android app since Android devices do not come with traceroute by default. I've encountered a couple stack overflow posts talking about solutions to this, but I have still run into challenges.
Traceroute on android - the top post on this thread links an Android Studio project that implements traceroute using ping. If I understand the algorithm correctly, it continually pings the destination IP, incrementing the time-to-live field to obtain information about intermediary routers. I've tried to recreate this behavior, but for certain values of TTL, the ping stalls and doesn't retrieve any router information. I'm not really sure why this happens. Here's a quick demo function I spun up... at some point in the loop the pings stall.
public static void smallTracerouteDemoShowingThatTheProgramStallsAtCertainTTLs() {
try {
String host = "google.com";
int maxTTL = 20;
for (int i = 1; i < maxTTL; i++) {
// Create a process that executes the ping command
Process p = Runtime.getRuntime().exec("ping -c 1 -t " + i + " " + host);
// Get a buffered reader with the information returned by the ping
BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
// Convert the BufferedReader to a string
String dataReturnedByPing = "";
for (String line; (line = br.readLine()) != null; dataReturnedByPing += "\n"+line);
// Print out information about each TTL
System.out.println("TTL = " + i + " out of " + maxTTL);
System.out.println(dataReturnedByPing);
System.out.println("========================================");
}
} catch (Exception e) {
e.printStackTrace();
}
}
how to run traceroute command through your application? - The solution on this thread suggests using BusyBox. I've not used BusyBox as yet, but it seems like I would have to embed BusyBox into my app to get things to work. After doing some research it looks like BusyBox provides numerous Linux commands through one executable. I'm a bit hesitant to explore this option because I really only need the traceroute command. In addition, I know that Android targets a few different CPU architectures, and I'm not sure if one executable will support them all.
I've also run into a github repository that takes another approach to running traceroute:
https://github.com/wangjing53406/traceroute-for-android - In this repository the author embeds the traceroute source code into the project and uses the NDK to build the source code along with the rest of his app. I really like this approach because it feels the most "correct." It uses a built traceroute instead of a Java-based implementation, so you can't find yourself in a situation where the Java implementation gives you one thing and the actual traceroute gives you another. When I open this project to experiment with it, my build fails. The top line says:
org.gradle.initialization.ReportedException: org.gradle.internal.exceptions.LocationAwareException: A problem occurred configuring root project 'traceroute-for-android-master'.
Any help on why this happens or ways to troubleshoot it would be fantastic.
For reference, the minimum SDK I am targeting is API 21 and I am running on Android Studio 3.3.0.
So, at this point I'm stumped. If you were trying to make an app that would let you execute traceroute commands, how would you do it? I really like the NDK approach because it guarantees you're getting true traceroute behavior. If you have any guides to getting that set up for my Android version/SDK, I would appreciate if you would post them. If you'd take another approach I'd to hear about it as well.
Thank you in advance.
What's the easiest way to execute a Python script from Java, and receive the output of that script? I've looked for different libraries like Jepp or Jython, but most appear out of date. Another problem with the libraries is that I need to be able to easily include a library with the source code (though I don't need to source for the library itself) if I use a library.
Because of this, would the easiest/most effective way be to simply do something like call the script with runtime.exec, and then somehow capture printed output? Or, even though it would be very painful for me, I could also just have the Python script output to a temporary text file, then read the file in Java.
Note: the actual communication between Java and Python is not a requirement of the problem I am trying to solve. This is, however, the only way I can think of to easily perform what needs to be done.
Not sure if I understand your question correctly, but provided that you can call the Python executable from the console and just want to capture its output in Java, you can use the exec() method in the Java Runtime class.
Process p = Runtime.getRuntime().exec("python yourapp.py");
You can read up on how to actually read the output from this resource:
http://www.devdaily.com/java/edu/pj/pj010016
import java.io.*;
public class JavaRunCommand {
public static void main(String args[]) {
String s = null;
try {
// run the Unix "ps -ef" command
// using the Runtime exec method:
Process p = Runtime.getRuntime().exec("ps -ef");
BufferedReader stdInput = new BufferedReader(new
InputStreamReader(p.getInputStream()));
BufferedReader stdError = new BufferedReader(new
InputStreamReader(p.getErrorStream()));
// read the output from the command
System.out.println("Here is the standard output of the command:\n");
while ((s = stdInput.readLine()) != null) {
System.out.println(s);
}
// read any errors from the attempted command
System.out.println("Here is the standard error of the command (if any):\n");
while ((s = stdError.readLine()) != null) {
System.out.println(s);
}
System.exit(0);
}
catch (IOException e) {
System.out.println("exception happened - here's what I know: ");
e.printStackTrace();
System.exit(-1);
}
}
}
There is also an Apache library (the Apache exec project) that can help you with this. You can read more about it here:
http://www.devdaily.com/java/java-exec-processbuilder-process-1
http://commons.apache.org/exec/
You can include the Jython library in your Java Project. You can download the source code from the Jython project itself.
Jython does offers support for JSR-223 which basically lets you run a Python script from Java.
You can use a ScriptContext to configure where you want to send your output of the execution.
For instance, let's suppose you have the following Python script in a file named numbers.py:
for i in range(1,10):
print(i)
So, you can run it from Java as follows:
public static void main(String[] args) throws ScriptException, IOException {
StringWriter writer = new StringWriter(); //ouput will be stored here
ScriptEngineManager manager = new ScriptEngineManager();
ScriptContext context = new SimpleScriptContext();
context.setWriter(writer); //configures output redirection
ScriptEngine engine = manager.getEngineByName("python");
engine.eval(new FileReader("numbers.py"), context);
System.out.println(writer.toString());
}
And the output will be:
1
2
3
4
5
6
7
8
9
As long as your Python script is compatible with Python 2.5 you will not have any problems running this with Jython.
I met the same problem before, also read the answers here, but doesn't found any satisfy solution can balance the compatibility, performance and well format output, the Jython can't work with extend C packages and slower than CPython. So finally I decided to invent the wheel myself, it took my 5 nights, I hope it can help you too: jpserve(https://github.com/johnhuang-cn/jpserve).
JPserve provides a simple way to call Python and exchange the result by well format JSON, few performance loss. The following is the sample code.
At first, start jpserve on Python side
>>> from jpserve.jpserve import JPServe
>>> serve = JPServe(("localhost", 8888))
>>> serve.start()
INFO:JPServe:JPServe starting...
INFO:JPServe:JPServe listening in localhost 8888
Then call Python from JAVA side:
PyServeContext.init("localhost", 8888);
PyExecutor executor = PyServeContext.getExecutor();
script = "a = 2\n"
+ "b = 3\n"
+ "_result_ = a * b";
PyResult rs = executor.exec(script);
System.out.println("Result: " + rs.getResult());
---
Result: 6
Jep is anther option. It embeds CPython in Java through JNI.
import jep.Jep;
//...
try(Jep jep = new Jep(false)) {
jep.eval("s = 'hello world'");
jep.eval("print(s)");
jep.eval("a = 1 + 2");
Long a = (Long) jep.getValue("a");
}
I've looked for different libraries like Jepp or Jython, but most seem to be very out of date.
Jython is not "a library"; it's an implementation of the Python language on top of the Java Virtual Machine. It is definitely not out of date; the most recent release was Feb. 24 of this year. It implements Python 2.5, which means you will be missing a couple of more recent features, but it is honestly not much different from 2.7.
Note: the actual communication between Java and Python is not a requirement of the aforementioned assignment, so this isn't doing my homework for me. This is, however, the only way I can think of to easily perform what needs to be done.
This seems extremely unlikely for a school assignment. Please tell us more about what you're really trying to do. Usually, school assignments specify exactly what languages you'll be using for what, and I've never heard of one that involved more than one language at all. If it did, they'd tell you if you needed to set up this kind of communication, and how they intended you to do it.
Jython approach
Java is supposed to be platform independent, and to call a native application (like python) isn't very platform independent.
There is a version of Python (Jython) which is written in Java, which allow us to embed Python in our Java programs. As usually, when you are going to use external libraries, one hurdle is to compile and to run it correctly, therefore we go through the process of building and running a simple Java program with Jython.
We start by getting hold of jython jar file:
https://www.jython.org/download.html
I copied jython-2.5.3.jar to the directory where my Java program was going to be. Then I typed in the following program, which do the same as the previous two; take two numbers, sends them to python, which adds them, then python returns it back to our Java program, where the number is outputted to the screen:
import org.python.util.PythonInterpreter;
import org.python.core.*;
class test3{
public static void main(String a[]){
PythonInterpreter python = new PythonInterpreter();
int number1 = 10;
int number2 = 32;
python.set("number1", new PyInteger(number1));
python.set("number2", new PyInteger(number2));
python.exec("number3 = number1+number2");
PyObject number3 = python.get("number3");
System.out.println("val : "+number3.toString());
}
}
I call this file "test3.java", save it, and do the following to compile it:
javac -classpath jython-2.5.3.jar test3.java
The next step is to try to run it, which I do the following way:
java -classpath jython-2.5.3.jar:. test3
Now, this allows us to use Python from Java, in a platform independent manner. It is kind of slow. Still, it's kind of cool, that it is a Python interpreter written in Java.
ProcessBuilder is very easy to use.
ProcessBuilder pb = new ProcessBuilder("python","Your python file",""+Command line arguments if any);
Process p = pb.start();
This should call python. Refer to the process approach here for full example!
https://bytes.com/topic/python/insights/949995-three-ways-run-python-programs-java
You can try using groovy. It runs on the JVM and it comes with great support for running external processes and extracting the output:
http://groovy.codehaus.org/Executing+External+Processes+From+Groovy
You can see in this code taken from the same link how groovy makes it easy to get the status of the process:
println "return code: ${ proc.exitValue()}"
println "stderr: ${proc.err.text}"
println "stdout: ${proc.in.text}" // *out* from the external program is *in* for groovy
First I would recommend to use ProcessBuilder ( since 1.5 )
Simple usage is described here
https://stackoverflow.com/a/14483787
For more complex example refer to
http://www.javaworld.com/article/2071275/core-java/when-runtime-exec---won-t.html
I've encountered problem when launching Python script from Java, script
was producing too much output to standard out and everything went bad.
The best way to achieve would be to use Apache Commons Exec as I use it for production without problems even for Java 8 environment because of the fact that it lets you execute any external process (including python, bash etc) in synchronous and asynchronous way by using watchdogs.
CommandLine cmdLine = new CommandLine("python");
cmdLine.addArgument("/my/python/script/script.py");
DefaultExecuteResultHandler resultHandler = new DefaultExecuteResultHandler();
ExecuteWatchdog watchdog = new ExecuteWatchdog(60*1000);
Executor executor = new DefaultExecutor();
executor.setExitValue(1);
executor.setWatchdog(watchdog);
executor.execute(cmdLine, resultHandler);
// some time later the result handler callback was invoked so we
// can safely request the exit value
resultHandler.waitFor();
Complete source code for a small but complete POC is shared here that addresses another concern in this post;
https://github.com/raohammad/externalprocessfromjava.git
First of all sorry for my poor English.
I want to know how the windows will do auto java update check behind the User Interface ?
The UI will just react based on our input which is in the link , http://java.com/en/download/help/java_update.xml#howto .
But , how windows checks the updates programmatically.
I wrote a small program in java ,
public class JavaLatestVersion {
public static void main(String[] args){
try {
BufferedReader br = new BufferedReader(new InputStreamReader(new URL(
"http://java.com/applet/JreCurrentVersion2.txt").openStream())) ;
String fullVersion = br.readLine();
System.out.println("fullVersion : "+fullVersion);
String version = fullVersion.split("_")[0];
String revision = fullVersion.split("_")[1];
System.out.println("Version " + version + " revision " + revision);
} catch (IOException e) {
e.printStackTrace();
}
}
}
My questions :
1. Is the above program is the reliable way to get the latest java version ? Or any other standard way to get the latest java version (Not in the computer) ?
2. Is windows use the same way to determine the latest java version ?
3. Is windows use this link for updates http://java.com/applet/JreCurrentVersion2.txt ?
Any one know the secret code behind how windows will check for latest java updates?
Thanks in advance.
Checking for Java updates is done by Java Auto Updater. It is ordinary application (which is ran when Windows starts up).
Yes, it is reliable way to get the latest version of Java (as updater can not only update Java, it can also update itself). But pay attention to firewall/group policy settings which can prohibit updater to access the Web.
Windows doesn't update Java.
Only debugging Java Auto Updater can help to determine what URL it uses.
Unfortunately, Java Auto Updater has only graphical interface and hides all work behind the scenes. So finding a "secret code" is not easy to do. All the more in many cases reverse-engineering non-open source software is illegal from a license point of view.
URL that you provided above doesn't works. Because it says 8.0_51. But latest version of Java on Downloads page is 8u65 / 8u66.
Seems that latest available version (as plain text) can be determined only by fetching http://www.oracle.com/technetwork/java/javase/downloads/index.html web page, then parsing it, handling cases when page is moved to another location, etc.
I have code which uses ScriptEngineManager, ScriptEngine class for executing JavaScript code using Java. But it works fine in Java SE, and doesn't work in Android - SDK show error of missing classes. Is it possible to execute JS code in Android? Thank you.
AndroidJSCore is a great one. And here is another little library I wrote for evaluating JavaScript:
https://github.com/evgenyneu/js-evaluator-for-android
jsEvaluator.evaluate("function hello(){ return 'Hello world!'; } hello();", new JsCallback() {
#Override
public void onResult(final String result) {
// get result here (optional)
}
});
It creates a WebView behind the scenes. Works on Android version 3 and newer.
You can use Webview which inherits View class. Make an XML tag and use findViewById() function to use in the activity. But to use the JavaScript, you can make a HTML file containing the JavaScript code. The example blelow might help.
Webview browser=(Webview) findViewById(R.main.browser); //if you gave the id as browser
browser.getSettings().setJavaScriptEnabled(true); //Yes you have to do it
browser.loadUrl("file:///android_asset/JsPage.html"); //If you put the HTML file in asset folder of android
Remember that the JS will run on WebView, not in native environment, thus you might experience a lag or slow FPS in emulator. However when using on an actual phone, the code may run fast, depending on how fast is your phone.
http://divineprogrammer.blogspot.com/2009/11/javascript-rhino-on-android.html will get you started. ScriptEngine is a java thing. Android doesn't have a JVM but a DalvikVM which is not identical but similar.
UPDATE 2018: AndroidJSCore has been superseded by LiquidCore, which is based on V8. Not only does it include the V8 engine, but all of Node.js is available as well.
Original answer:
AndroidJSCore is an Android Java JNI wrapper around Webkit's JavaScriptCore C library. It is inspired by the Objective-C JavaScriptCore Framework included natively in iOS 7. Being able to natively use JavaScript in an app without requiring the use of JavaScript injection on a bloated, slow, security-constrained WebView is very useful for many types of apps, such as games or platforms that support plugins. However, its use is artificially limited because the framework is only supported on iOS. Most developers want to use technologies that will scale across both major mobile operating systems. AndroidJSCore was designed to support that requirement.
For example, you can share Java objects and make async calls:
public interface IAsyncObj {
public void callMeMaybe(Integer ms, JSValue callback) throws JSException;
}
public class AsyncObj extends JSObject implements IAsyncObj {
public AsyncObj(JSContext ctx) throws JSException { super(ctx,IAsyncObj.class); }
#Override
public void callMeMaybe(Integer ms, JSValue callback) throws JSException {
new CallMeLater(ms).execute(callback.toObject());
}
private class CallMeLater extends AsyncTask<JSObject, Void, JSObject> {
public CallMeLater(Integer ms) {
this.ms = ms;
}
private final Integer ms;
#Override
protected JSObject doInBackground(JSObject... params) {
try {
Thread.sleep(ms);
} catch (InterruptedException e) {
Thread.interrupted();
}
return params[0];
}
#Override
protected void onPostExecute(JSObject callback) {
JSValue args [] = { new JSValue(context,
"This is a delayed message from Java!") };
try {
callback.callAsFunction(null, args);
} catch (JSException e) {
System.out.println(e);
}
}
}
}
public void run() throws JSException {
AsyncObj async = new AsyncObj(context);
context.property("async",async);
context.evaluateScript(
"log('Please call me back in 5 seconds');\n" +
"async.callMeMaybe(5000, function(msg) {\n" +
" alert(msg);\n" +
" log('Whoomp. There it is.');\n" +
"});\n" +
"log('async.callMeMaybe() has returned, but wait for it ...');\n"
);
}
I was also looking for a way to run javascript on Android and came across j2v8 library. This is a java wrapper for Google's v8 engine.
To use it add a dependency:
compile 'com.eclipsesource.j2v8:j2v8_android:3.0.5#aar'
It has pretty simple api, but I haven't found any docs online apart from javadoc in maven repository. The articles on their blog are also useful.
Code sample from this article:
public static void main(String[] args) {
V8 runtime = V8.createV8Runtime();
int result = runtime.executeIntegerScript(""
+ "var hello = 'hello, ';\n"
+ "var world = 'world!';\n"
+ "hello.concat(world).length;\n");
System.out.println(result);
runtime.release();
}
The javax.script package is not part of the Android SDK. You can execute JavaScript in a WebView, as described here. You perhaps can use Rhino, as described here. You might also take a look at the Scripting Layer for Android project.
You can use Rhino library to execute JavaScript without WebView.
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();
}
You can see more details at my post.
Given that ScriptEngineManager and ScriptEngine are part of the JDK and Android SDK is not the same thing as the JDK I would say that you can't use these classes to work with JavaScript under Android.
You can check the Android SDK's reference documentation/package index to see what classes are included (what can you work on Android out of the box) and which of them are missing.
I just found the App JavaScript for Android, which is the Rhino JavaScript engine for Java. It can use all Java-classes, so it has BIG potential. The problem is it might be slow, since it is not really optimized (heavy CPU load). There is another JavaScript engine named Nashorn, but that unfortunately doesn't works on Google's DalvikVM Java engine (does not support the optimizations of Oracle Java engine). I hope Google keeps up with that, I would just love it!
If you want to run some javascript code on chrome browser as per the question copy this code and paste it into address bar:
data:text/html, <html contenteditable> <title> Notepad </title> <script> alert('Abhasker Alert Test on Mobile'); </script> </html>
How can I use java to get a js file located on a web server, then execute the function in the js file and get the result and use the result in java.
Can you guys give me some code snippet? Great thanks.
You can use the scripting engine built into Java:
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
public static void main(String[] args) throws Exception {
ScriptEngineManager mgr = new ScriptEngineManager();
ScriptEngine engine = mgr.getEngineByName("JavaScript");
Object result = engine.eval("my-java-script-code")
System.out.println("Result returned by Javascript is: " + result);
}
Here is a more elaborate example.
There's three steps to this process:
Fetch the JS file from the server.
Execute some JS function from the file.
Extract the result.
The first step is fairly simple, there are lots of HTTP libraries in Java that will do this - you effectively want to emulate the simple functionality of something like wget or curl. The exact manner in which you do this will vary depending on what format you want the JS file in for the next step, but the process to get hold of the byte stream is straightforward.
The second step will require executing the JS in a Javascript engine. Java itself cannot interpret Javascript, so you'd need to obtain an engine to run it in - Rhino is a common choice for this. Since you'd need to run this outside of Java, you'll likely have to spawn a process for execution in Rhino using ProcessBuilder. Additionally, depending on the format of the Javascript you might need to create your own "wrapper" javascript that functions like a main class in Java and calls the method in question.
Finally you need to get the result out - obviously you don't have direct access to JavaScript objects from your Java program. The easiest way is going to be for the JS program to print the result to standard out (possibly serialising as something like JSON depending on the complexity of the object), which is being streamed directly to your Java app due to the way you launched the Rhino process. This could be another job for your JS wrapper script, if any. Otherwise, if the JS function has observable side effects (creates a file/modifies a database) then you'll be able to query those directly from Java.
Job done.
I hope you realise this question is far too vague to get full answers. Asking the public to design an entire system goes beyond the point where you'll get useful, actionable responses.
There are plenty of examples on the web of how to download a file from a URL.
Suns version of the JDK and JRE includes the Mozilla Rhino scripting engine.
Assuming you have stored the contents of the javascript file in a string called 'script', you can execute scripts as follows
String result = null;
ScriptEngineManager mgr = new ScriptEngineManager();
ScriptEngine jsEngine = mgr.getEngineByName("JavaScript");
try {
jsEngine.eval(script);
result = jsEngine.get("result")
} catch (ScriptException ex) {
ex.printStackTrace();
}
The result will be extracted from the engine and stored in the 'result' variable.
The is a tutorial on scripting in Java that might be useful.