WebView threads never stop (WebViewCoreThread, CookieSyncManager, http[0-3])

Question

I use a WebView to display some internet content on one of our app's Activities.
The problem is that when the user switches out of this activity, WebView's threads keep running!
The problematic threads are:

Thread [<17> WebViewCoreThread] (Running) Thread [<25> CookieSyncManager] (Running) Thread [<19> http0] (Running) Thread [<29> http1] (Running) Thread [<31> http2] (Running) Thread [<33> http3] (Running) 

Pausing each one of these threads, and checking what it is busy doing:

Thread [<17> WebViewCoreThread] (Suspended)     Object.wait(long, int) line: not available [native method]     MessageQueue(Object).wait() line: 288     MessageQueue.next() line: 148     Looper.loop() line: 110     WebViewCore$WebCoreThread.run() line: 471     Thread.run() line: 1060  Thread [<25> CookieSyncManager] (Suspended)     Object.wait(long, int) line: not available [native method]     MessageQueue(Object).wait(long) line: 326     MessageQueue.next() line: 144     Looper.loop() line: 110     CookieSyncManager(WebSyncManager).run() line: 90     Thread.run() line: 1060  Thread [<19> http0] (Suspended)     Object.wait(long, int) line: not available [native method]     RequestQueue(Object).wait() line: 288     ConnectionThread.run() line: 93 

I wonder how can I tell the Looper in each of those threads to quit.

I tried calling webView.destroy() in the activity's onPause() method, but it had no influence.
When I disable the call for opening a web page in the webView ( webView.loadUrl(...) ), those threads naturally are not started, and therefore don't stay on after leaving the activity.

Any ideas as to how I can make WebView's threads stop after leaving their activity?

Answer 1

You should be able to stop / resume these threads by calling the onPause / onResume on the webview.

Those are however hidden, so you will need to do it through reflection. The following code worked for me:

Class.forName("android.webkit.WebView").getMethod("onPause", (Class[]) null).invoke(webView, (Object[]) null); 

Where webView is the instance of WebView.

Also see: http://code.google.com/p/android/issues/detail?id=10282

Answer 2

My solution, in extended webview class(tested in android 2.2, andriod 2.3, android 3.1):

 private boolean is_gone = false;  public void onWindowVisibilityChanged(int visibility) {      super.onWindowVisibilityChanged(visibility);      if (visibility == View.GONE) {          try {              WebView.class.getMethod("onPause").invoke(this); //stop flash          } catch (Exception e) {}          this.pauseTimers();          this.is_gone = true;      } else if (visibility == View.VISIBLE) {          try {              WebView.class.getMethod("onResume").invoke(this); //resume flash          } catch (Exception e) {}          this.resumeTimers();          this.is_gone = false;      }  }  public void onDetachedFromWindow() { //this will be trigger when back key pressed, not when home key pressed      if (this.is_gone) {          try {              this.destroy();          } catch (Exception e) {}      }  }