By the way, this code is located in a subclassed WebView.
On Jan 18, 9:53 am, tatebn <brandonnt...@gmail.com> wrote:
> I'm trying to evaluate javascript with a semaphore lock. I need to
> query some web content about which context menus to show and need it
> to be synchronous. When I try to acquire the semaphore the thread
> locks without the javascript being evaluated and my javascript
> interface method being called.
>
> Here's my code.
>
> private Semaphore returnSemaphore = new Semaphore(0);
> private String returnValue;
>
> public String getJSValue(String expression)
> {
> String code =
> "javascript:_JSEval.setValue((function(){try{return "
> + expression
> + "+\"\";}catch(js_eval_err){return '';}})());";
> //String code = "javascript: alert('here');";
> Log.d(TAG, "eval: " + code);
>
> this.loadUrl(code);
>
> try {
> Log.d(TAG, "eval: about to acquire semaphore, " +
> returnSemaphore.availablePermits());
>
> returnSemaphore.acquire();
>
> Log.d(TAG, "past semaphore acquire");
>
> return returnValue;
> } catch (InterruptedException e) {
> Log.e(TAG, "eval: Interrupted", e);
> }
> return null;
>
> }
>
> @SuppressWarnings("unused")
> private class JSEval
> {
> public void setValue(String value)
> {
> Log.i(TAG, "eval: in set value");
> //if (value != null) {
> returnValue = value;
> //}
> returnSemaphore.release();
> }
> }
>
> If I remove the semaphore acquire call, I get a result in setValue, so
> I know the interface is working.
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