How to talk with Javascript function from SWT

Question

There is a javascript xxx_return () function in my HTML file that will return a string value. Is there a way that I can use this value from the Java level?

I use the SWT shell to display this html. Does SWT provide any function to get the return values ​​of a script function?

edit:

My code looks something like this: package test.html.simulation;

import org.eclipse.swt.SWT; import org.eclipse.swt.SWTException; import org.eclipse.swt.browser.Browser; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.Shell; public class BrowserExample{ public static void main(String[] args) { Display display = new Display(); final Shell shell = new Shell(display); String html=""; Object ob=null; shell.setText("Browser Example"); shell.setSize(500, 350); final Browser browser = new Browser(shell, SWT.NONE); browser.setBounds(5, 75, 600, 400); browser.setUrl("http://localhost/test/tryxml.html"); shell.open(); //System.out.println(browser.getUrl()); //try { html=(String)browser.evaluate("returnHTML();"); }/*catch(SWTException e) { System.out.println(e.getMessage()); }*/ System.out.println(html); while (!shell.isDisposed()) { if (!display.readAndDispatch()) display.sleep(); } display.dispose(); } 

This code gives me a SWT exception like Object:

 Exception in thread "main" org.eclipse.swt.SWTException: Object expected at org.eclipse.swt.browser.WebBrowser$EvaluateFunction.function(Unknown Source) at org.eclipse.swt.browser.WebSite.Invoke(Unknown Source) at org.eclipse.swt.browser.WebSite$7.method6(Unknown Source) at org.eclipse.swt.internal.ole.win32.COMObject.callback6(Unknown Source) at org.eclipse.swt.internal.ole.win32.COM.VtblCall(Native Method) at org.eclipse.swt.internal.ole.win32.IDispatch.Invoke(Unknown Source) at org.eclipse.swt.ole.win32.OleAutomation.invoke(Unknown Source) at org.eclipse.swt.ole.win32.OleAutomation.invoke(Unknown Source) at org.eclipse.swt.browser.IE.execute(Unknown Source) at org.eclipse.swt.browser.WebBrowser.evaluate(Unknown Source) at org.eclipse.swt.browser.Browser.evaluate(Unknown Source) at test.html.simulation.BrowserExample.main(BrowserExample.java:29) 

In java script, I wrote a function in a script tag, for example:

 <script> function returnHTML() { var str=document.body.innerHTML; //alert(str); return str; } </script> 

Can anyone find a mistake in this ?. I do not understand where she gets into the error.

Thanks.

Answer 1

Use the SWT Browser object. Then you can simply use String result = (String)Browser.evaluate("xxx_return();") .

Answer 2

I found it, an exception was thrown since Browser.evaluate () was called before the page was loaded into the shell. I added a ProgressListener to find out about the completion and tried to call him.

 browser.addProgressListener(new ProgressListener() { public void changed(ProgressEvent event) { } public void completed(ProgressEvent event) {String htm; htm=(String)browser.evaluate("return returnHTML()"); System.out.println(htm); } }); 

Thanks everyone

Answer 3

In addition to the above solutions, add "return" before the expression. Also, depending on what you are evaluating, the completed event can be ignored. The following expression just works.

 browser.evaluate("return 4 + 5;") 

Of course, if you evaluate javascript from a page loaded into the browser, the rating should be called after the event has ended, otherwise javascript may not have been loaded.